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Infantile osteopetrosisIInfantile osteopetrosisInfantile osteopetrosisEnglishGeneticsChild (0-12 years);Teen (13-18 years)BodyBonesConditions and diseasesCaregivers Adult (19+)NA2011-09-01T04:00:00Z10.300000000000044.90000000000001627.00000000000Health (A-Z) - ConditionsHealth A-Z<p>Information for parents about infantile osteopetrosis, a rare genetic condition that may cause fractures, short stature (height), recurrent infections, hearing loss and vision problems.</p><h2>What is infantile osteopetrosis?</h2> <p>Infantile osteopetrosis (say: oss-tee-oh-peh-TRO-siss) is a genetic condition that may result in: </p> <ul> <li>fractures</li> <li>short stature (height)</li> <li>recurrent infections</li> <li>hearing loss</li> <li>vision problems</li> </ul> <p>Other names you may hear for this condition are early onset osteopetrosis and malignant infantile osteopetrosis. </p> <p>This condition is quite rare and is believed to affect about one in 200,000 people. </p> <p>There are several different forms of osteopetrosis: infantile, juvenile and adult onset. In general, infantile osteopetrosis is the most severe form, while adult-onset osteopetrosis is the mildest form.<br></p><h2>Key points</h2> <ul> <li>Infantile osteopetrosis is a genetic condition that may result in fractures, short stature, recurrent infections, hearing loss and vision problems.</li> <li>Children with infantile osteopetrosis need to be followed carefully by a health care team made up of different specialists because they may develop health problems.</li> <li>Genetic counselling can help families understand infantile osteopetrosis, the options for managing it, and the chances that other children will also be affected.</li> </ul><h2>Osteopetrosis is a genetic condition</h2><p>Genetic means related to genes. Each of us inherits our genes from our parents. They provide our bodies with instructions that influence our health, looks and behaviour. In general, each person has two copies of every gene. </p><p>Infantile osteopetrosis is caused by a mutation (change) in each copy of a gene. One mutation is inherited from the mother and the other from the father. To date, there are several genes known to cause infantile osteopetrosis, including CLCN7, OSTM1, TCIRG1, TNFSF11, PLEKHM1 and TNFRSF11A. </p><p>Infantile osteopetrosis is inherited in an autosomal recessive pattern. This means that:</p><ul><li>A person with infantile osteopetrosis has a mutation in each copy of the gene.</li><li>Each parent carries a mutation in one copy of the gene. The other copy of the gene works normally and because of this, the parent does not show signs and symptoms of infantile osteopetrosis. This person is called a carrier of infantile osteopetrosis.</li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Inheritance of infantile osteopetrosis</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Inheritance_MED_ILL_EN.jpg" alt="Chromosome distribution from parents each carrying a gene with a mutation" /> <figcaption class="asset-image-caption">Infantile osteopetrosis is caused by mutations in both copies of one of the genes known to cause this condition. In this example, both healthy parents are carriers of the gene with a mutation. Their baby can inherit one of the following gene combinations: one, two or no copies of the gene with a mutation. If a baby inherits no copies or just one copy of the gene with a mutation, the baby will not have infantile osteopetrosis. It is only when a baby inherits two copies of the gene with a mutation that the baby will have infantile osteopetrosis.</figcaption> </figure> <p>To learn more about genetics, visit: <a href="/Article?contentid=343&language=English">Genetic counselling</a>.</p><h2>Diagnosing infantile osteopetrosis</h2><p>A diagnosis of infantile osteopetrosis is made on the basis of physical examination and X-ray findings. X-rays shows thickening and increased density of bones and bone-within-bone appearance. The diagnosis may be confirmed by DNA testing (blood test).</p><h3>Infantile osteopetrosis can be diagnosed before birth</h3><p>Before birth, infantile osteopetrosis can be diagnosed by testing DNA taken from the fetus. This can be obtained in one of the following ways:</p><ul><li>by amniocentesis after the 15th week of pregnancy </li><li>by chorionic villus sampling (CVS) between the 11th and 14th week of pregnancy</li></ul><p>These methods are used for high-risk pregnancies, for instance if the parents have another child diagnosed with infantile osteopetrosis. </p><p>To be eligible for this testing, the mutations in the gene responsible for causing infantile osteopetrosis must be known. This means that the child with the condition must have genetic testing.<br></p><p>Infantile osteopetrosis may also be diagnosed before birth using ultrasound as early as 14 weeks' gestation. However, it is possible to have a normal ultrasound and still have a baby with infantile osteopetrosis. </p> <figure class="asset-c-100"> <span class="asset-image-title">X-ray of healthy vs. infantile osteopetrotic thigh bones</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Xray_MED_ILL_EN.png" alt="X-ray of thighs with healthy bone thickness and density and x-ray of thighs with increased bone thickness and density" /> <figcaption class="asset-image-caption">The thigh bones in the right X-ray show the effects of infantile osteopetrosis. The bones are thicker and have a higher bone density making them appear whiter on the X-ray. </figcaption> </figure><h2>Treatment of infantile osteopetrosis</h2><p>Children with infantile osteopetrosis need attentive, informed care from their parents and health-care providers. </p><p>The goals of treatment are:</p><ul><li>to help children with infantile osteopetrosis adapt socially and physically</li><li>to treat the symptoms</li></ul><h3>Transplantation of hematopoietic stem cells</h3> <p>The most effective treatment option available for infantile osteopetrosis is the transplantation of hematopoietic stem cells. These are the blood stem cells that come from the bone marrow or blood. It is a life-saving procedure with some risks. When successful, it prevents the progression of symptoms and improves bone health. Other problems like vision loss and dental and orthopaedic problems can still happen. </p><p>For more information, please see the <a href="/Article?contentid=2477&language=English">Blood and Marrow Transplant Resource Centre</a> on AboutKidsHealth.ca.</p><h3>Calcium supplements</h3><p>People with infantile osteopetrosis need to have the calcium levels in their blood and urine monitored. If your child's calcium levels are low, your child will need supplements. </p><h3>Transfusions</h3><p>Your child should have a complete blood count at least once every year. Depending on the levels, your child may need transfusions of red blood cells and platelets. </p><p>For more information, please see the <a href="/Article?contentid=1107&language=English">blood transfusion</a> and <a href="/Article?contentid=32&language=English">blood donation</a> articles on AboutKidsHealth.ca.</p> <h3>Treatment of infections</h3><p>If your child often has infections, your child may need antibiotics. </p><h3>Treatment of vision problems</h3><p>Your child should have an eye examination at least once a year. Children with vision problems may need surgery to release the compression of the optic nerve. </p><h3>Treatment of fractures</h3><p>Recurrent fractures need management by an orthopaedic surgeon. Special attention is needed because the fracture may take a long time to heal. Patients may need medication for joint pains. </p><h3>Treatment of dental problems</h3><p>Children with osteopetrosis are more likely to have dental problems like abscesses, cysts and teeth that take longer to come in. Your child should see a dentist regularly.</p><h2>How infantile osteopetrosis affects the body</h2><h3>Bone and dental problems</h3><p>Osteopetrosis is a disorder of bone development in which the bones become thickened. Normally, small areas of bone are constantly being broken down by special cells called osteoclasts, then made again by cells called osteoblasts. This is called bone remodeling, and it helps keep the bones healthy.</p> <figure class="asset-c-100"> <span class="asset-image-title">Bone remodeling cells</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_bone_cells_MED_ILL_EN.jpg" alt="Osteoclast and osteoblast on bone" /> <figcaption class="asset-image-caption">Within our bones are special cells that constantly break down bone and build new bone. Osteoclasts break down bone and osteoblasts make new bone.</figcaption> </figure> <p>In osteopetrosis, the cells that break down bone (osteoclasts) do not work properly, so there is an imbalance between these two functions. This leads to the bones becoming thicker and not as healthy. This can lead to: </p><ul><li>bone fractures </li><li>less overall bone growth, causing short stature</li><li>a thicker skull bone, which may cause teeth to come out later than expected</li><li>larger head size</li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Osteopetrotic bone</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_bone_cycle_MED_ILL_EN.jpg" alt="Osteopetrotic bone with abnormal osteoclasts compared to a healthy bone" /> <figcaption class="asset-image-caption">Normally, our bones are constantly being broken down by osteoclasts and made again by osteoblasts. In osteopetrosis, the osteoclasts are abnormal and cannot break down bone but osteoblasts continue to make new bone. This imbalance results in thicker bones that are not as healthy.</figcaption> </figure> <h3>Problems with bone marrow and blood cells </h3><p>Bone marrow makes new blood cells. It is found inside the bones. In people with infantile osteopetrosis, because the cells that break down bone do not work properly, the space where the bone marrow is found is smaller or even missing. This means there is less bone marrow, so fewer blood cells are made. This can lead to:</p><ul><li>Anemia because of low red blood cells. Symptoms of anemia include pale skin and lack of energy.</li><li>Bleeding problems because of low platelets. Platelets are blood cells needed for clotting to help stop bleeding.</li><li>Many infections due to low white blood cells. White blood cells are needed to fight infections. </li></ul><h3>Problems due to thickening of skull bones</h3><p>The skull bone of people with infantile osteopetrosis is thickened, which can lead to: </p><ul><li>compression of some nerves, causing vision problems and weakness of facial muscles </li><li>narrow nasal sinus, causing chronic nasal congestion</li></ul><p>Thickening of the bones of the ear can cause compression of the nerves, resulting in hearing loss.</p><h3>Calcium and parathyroid levels</h3><p>Children with infantile osteopetrosis have lower levels of calcium and parathyroid hormone in their blood than normal. This may sometimes lead to increased irritability and seizures if it is not managed. These seizures are often the first sign of infantile osteopetrosis. </p><h3>Life expectancy</h3><p>With bone marrow failure and recurrent infections, some babies with infantile osteopetrosis may die before two years of age. Without treatment, most die by the age of ten. Transplantation of hematopoietic stem cells (see below) is the most promising treatment for long-term survival. <br></p><h2>Resources and support</h2><p>The following organizations and sites can offer more information, support and contact with other affected individuals and their families.</p><h3>The OsteoPETrosis Society (OPETS)</h3><p> <a href="http://www.osteopetrosis.org/">www.osteopetrosis.org</a>.</p><h3>Osteopetrosis Support Trust</h3><p> <a href="https://www.osteopetrosis-support-trust.org.uk/">www.osteopetrosis-support-trust.org.uk</a>.</p><h3>National Institute of Arthritis and Musculoskeletal and Skin Diseases</h3><p> <a href="https://www.niams.nih.gov/">www.niams.nih.gov</a>.</p><h3>The Paget Foundation</h3><p> <a href="https://www.iofbonehealth.org/national-societies/1284">www.iofbonehealth.org/national-societies/1284</a>.</p>
Ostéopétrose infantileOOstéopétrose infantileInfantile osteopetrosisFrenchGeneticsChild (0-12 years);Teen (13-18 years)BodyBonesConditions and diseasesCaregivers Adult (19+)NA2011-09-01T04:00:00Z10.000000000000047.00000000000001614.00000000000Health (A-Z) - ConditionsHealth A-Z<h2>Qu’est-ce que l’ostéopétrose infantile? </h2> <p>L’ostéopétrose infantile est une maladie génétique entraînant les conséquences suivantes :</p> <ul> <li>des fractures;</li> <li>une petite taille (grandeur);</li> <li>des infections récurrentes;</li> <li>une déficience auditive;</li> <li>des problèmes de vision.</li> </ul> <p>D’autres appellations de cette maladie sont l’ostéopétrose précoce et l’ostéopétrose infantile maligne. </p> <p>Cette maladie est assez rare dont on estime que la prévalence se situe à 1 pour 200 000 personnes. </p> <p>Il existe plusieurs formes d’ostéopétrose : infantile, juvénile et adulte. En général, l’ostéopétrose infantile est la forme la plus grave, alors que l’ostéopétrose développé à l’âge adulte est la forme la plus légère.</p><h2>À retenir</h2> <ul> <li>L’ostéopétrose infantile est une maladie génétique qui pourrait entraîner des fractures, la petite taille (grandeur), des infections récurrentes, la déficience auditive, et des problèmes de vision.</li> <li>L’enfant atteint de l’ostéopétrose infantile doit être suivi de près par une équipe soignante composée de spécialistes de différents domaines, car il peut développer des problèmes de santé.</li> <li>Les consultations génétiques peuvent aider les familles à comprendre l’ostéopétrose infantile et les options de gestion, et à évaluer le risque que d’autres enfants soient également touchés.</li> </ul><h2>Ostéopétrose est une maladie génétique</h2><p>Génétique signifie un lien aux gènes. Chaque personne hérite ses gènes de ses parents. Les gènes fournissent à notre corps des instructions qui influent sur notre santé, apparence et comportement. En général, chaque personne a deux exemplaires de chaque gène. </p><p>L’ostéopétrose infantile est provoquée par une mutation (modification) dans chaque exemplaire du gène. Une mutation est héritée de la mère et l’autre du père. À ce jour, on connaît plusieurs gènes qui peuvent causer l’ostéopétrose infantile, dont CLCN7, OSTM1, TCIRG1, TNFSF11, PLEKHM1 et TNFRSF11A.</p><p>L’ostéopétrose infantile est hérité d’une manière récessive autosomique. Ceci signifie le suivant :</p><ul><li>Une personne atteinte d’ostéopétrose infantile a une mutation dans chaque exemplaire du gène.</li><li>Chaque parent a une mutation dans un exemplaire du gène. L’autre exemplaire du gène fonctionne normalement, à cause duquel le parent ne présente pas de signes ou symptômes de l’ostéopétrose infantile.</li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Ostéopétrose infantile héréditaire </span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Inheritance_MED_ILL_FR.jpg" alt="Distribution des chromosomes des parents portant une mutation génétique chacun" /> <figcaption>L'ostéopétrose infantile est causée par la mutation dans les deux exemplaires des gènes, de l'un des gènes qui cause la maladie. Dans cet exemple, les deux parents en santé sont porteurs de la mutation génétique. Leur bébé peut hériter de l'une des combinaisons de gènes suivantes : un, deux ou aucun exemplaire du gène comportant la mutation. Si un bébé n'hérite d'aucun exemplaire ou d'un seul exemplaire du gène comportant la mutation, le bébé ne sera pas atteint d'ostéopétrose infantile. C'est seulement lorsque le bébé hérite de deux exemplaires du gène comportant la mutation qu'il sera atteint d'ostéopétrose infantile.</figcaption> </figure><h2>Le diagnostic de l’ostéopétrose infantile</h2><p>On arrive à un diagnostic de l’ostéopétrose infantile au moyen d’un examen physique et des résultats de l’analyse aux rayons X. Les résultats de l’analyse aux rayons X révéleront un épaississement et une densité accrue des os, ainsi qu’une image d’os dans l’os. Le diagnostic peut être confirmé par l’analyse de l’ADN (prise de sang).</p><h3>L’ostéopétrose infantile peut être diagnostiquée avant la naissance</h3><p>Avant la naissance, l’ostéopétrose infantile peut être diagnostiquée par l’analyse de l’ADN prise du fœtus, obtenu d’une des deux façons suivantes :</p><ul><li>par l’amniocentèse après la 15e semaine de la grossesse;</li><li>par le prélèvement de villosités choriales (PVC) effectué entre la 11e et la 14e semaine de la grossesse.<br></li></ul><p>Ces méthodes sont adoptées pour des grossesses à risque élevé, par exemple si les parents ont un autre enfant ayant le diagnostic de l’ostéopétrose infantile.</p><p>Pour qu’on puisse faire ces tests, il faut qu’on détermine les mutations dans le gène responsable de l’ostéopétrose infantile. Ceci signifie que l’enfant atteint de la maladie doit subir des tests génétiques.</p><p>Le diagnostic de l’ostéopétrose infantile avant la naissance peut être réalisé également par l’échographie aussi tôt que 14 semaines gestationnelles. Cependant, il est possible le bébé ait l’ostéopétrose infantile même après que l’échographie n’affiche rien d’anormal.</p> <figure class="asset-c-100"> <span class="asset-image-title">Rayon X de fémurs en santé par rapport à des fémurs atteints d'ostéopétrose infantile</span><img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Xray_MED_ILL_FR.png" alt="Images de rayon X des fémurs, l’un avec l’épaisseur et la densité d’un os en santé et l’autre avec l’os plus épais et dense" /><figcaption class="asset-image-caption">Les fémurs sur le rayon X montrent les conséquences de l'ostéopétrose infantile. Les os sont plus épais et leur densité osseuse est plus élevée, ce qui les fait paraître plus blancs sur le rayon X. </figcaption> </figure><h2>Traitement de l’ostéopétrose infantile</h2> <p>Des enfants atteints de l’ostéopétrose infantile ont besoin de soins attentifs et avisés de la part de leurs parents et des fournisseurs de soins de santé. Les objectifs du traitement sont les suivants :</p> <ul> <li>aider les enfants atteints de l’ostéopétrose infantile à s’adapter sur le plan social et physique;</li> <li>traiter les symptômes.</li> </ul> <h3>Transplantation des cellules souches hématopoïétiques</h3> <p>L’option de traitement la plus efficace pour l’ostéopétrose infantile est la transplantation de cellules souches hématopoïétiques. Ce sont des cellules sanguines provenant de la moelle osseuse ou du sang. C’est une intervention salutaire, mais elle comporte certains risques. Le succès de cette intervention a pour résultat la prévention de la progression des symptômes et une amélioration de la santé des os. D’autres problèmes tels que la perte de la vision et des problèmes d’ordre dentaire et orthopédique pourraient cependant survenir. </p> <p>Pour plus de renseignements, veuillez visiter la section intitulée Greffe de sang et de moelle osseuse</p> <h3>Suppléments de calcium</h3> <p>Les personnes atteintes de l’ostéopétrose infantile doivent surveiller leur niveau de calcium dans le sang et dans l’urine. Si votre enfant affiche un niveau de calcium bas, la supplémentation en calcium sera recommandée.</p> <h3>Transfusions</h3> <p>Votre enfant doit subir une formule sanguine au moins une fois par an. En fonctions des niveaux affichés, la transfusion des globules rouges et des plaquettes pourrait être recommandée.</p> <p>Pour plus de renseignements, veuillez visiter la section intitulée Blood Donation and Blood Transfusion (en anglais seulement).</p> <h3>Traitement des infections</h3> <p>Si votre enfant attrape souvent des infections, un traitement antibiotique sera recommandé</p> <h3>Traitement des problèmes de vision</h3> <p>Votre enfant doit subir un test de vision au moins une fois par an. Des problèmes de vision chez des enfants pourraient nécessiter une intervention chirurgicale pour dégager la compression du nerf optique. </p> <h3>Traitement des fractures</h3> <p>Des fractures récurrentes doivent être traitées par un chirurgien orthopédiste. Il faut y prêter une attention particulière, car la guérison de la fracture risque de prendre beaucoup de temps. Les patients pourraient avoir besoin des médicaments pour soulager les douleurs articulaires. </p> <h3>Traitement des problèmes dentaires</h3> <p>Les enfants atteints de l’ostéopétrose sont plus susceptibles d’avoir des problèmes dentaires comme des abcès, des kystes, et des dents qui prennent plus de temps pour sortir. Votre enfant devrait consulter un dentiste régulièrement.</p><h2>Comment l’ostéopétrose infantile touche notre corps?</h2><h3>Problèmes osseux et dentaires</h3><p>L’ostéopétrose est un trouble du développement osseux qui entraîne l’épaississement des os. Normalement, de petites parties des os sont constamment en train d’être décomposées par des cellules spéciales appelées des ostéoclastes, pour être reconstituées par la suite par des cellules appelées ostéoblastes. Ce processus s’appelle le remodelage osseux, et il aide à garder les os en santé.</p> <figure class="asset-c-100"> <span class="asset-image-title">Cellules qui effectuent le remodelage osseux</span><img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_bone_cells_MED_ILL_FR.jpg" alt="Un ostéoclaste et un ostéoblaste sur un os" /><figcaption class="asset-image-caption">À l'intérieur de nos os, il y a des cellules qui détruisent la matière osseuse et la reconstruisent de façon continue. Les ostéoclastes détruisent les os et les ostéoblastes les reconstruisent.</figcaption> </figure> <p>Chez les personnes atteintes de l’ostéopétrose, les cellules qui décomposent l’os (les ostéoclastes) ne fonctionnent pas bien, ayant pour conséquence un déséquilibre entre ces deux fonctions. Par conséquent, les os deviennent plus épais et ne sont plus en santé comme il faut. L’ostéopétrose peut entraîner les conséquences suivantes :</p><ul><li>des fractures de l’os;</li><li>une croissance osseuse moindre, provoquant une petite taille (grandeur);</li><li>un os crânien plus épais, qui peut causer les dents de sortir plus tard que d’habitude;</li><li>une taille de tête plus importante.</li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Os ostéopétrotique</span><img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_bone_cycle_MED_ILL_FR.jpg" alt="Un os ostéopétrotique avec les ostéclastes abnormaux comparé à un os en santé" /><figcaption class="asset-image-caption">En règle générale, notre os est constamment détruit par les ostéoclastes et reconstruit par les ostéoblastes. Dans les cas d'ostéopétrose, les ostéoclastes ne sont pas normaux et n'arrivent pas à détruire l'os, mais les ostéoblastes continuent à en former. Ce déséquilibre a pour résultat des os plus épais qui ne sont pas en santé.</figcaption> </figure> <h3>Problèmes liés à la moelle osseuse et des cellules sanguines </h3><p>La moelle osseuse produit de nouvelles cellules sanguines. Elle se retrouve à l’intérieur des os. Chez des personnes atteintes de l’ostéopétrose infantile, à cause du fonctionnement inadéquat des cellules qui décomposent l’os l’espace où se retrouve la moelle osseuse est moins importante et même carrément manquante. Ceci a pour résultat une quantité moins importante de moelle osseuse, entraînant la production de moins de cellules sanguines. Ceci peut entraîner les conséquences suivantes: </p><ul><li>l’anémie, à cause de la numérotation globulaire moins importante des cellules rouges des symptômes de l’anémie comprennent une peau plus pâle et une diminution d’énergie;</li><li>des problèmes de saignement à cause d’une numération plaquettaire basse. Des plaquettes sont des cellules sanguines nécessaires pour la coagulation sanguine qui aide à arrêter le saignement;</li><li>de nombreuses infections en raison de la numérotation globulaire moins importante des cellules blanches. Les globules blancs sont nécessaires pour combattre les infections</li></ul><h3>Problèmes attribuables à l’épaississement des os crâniens</h3><p>L’os crânien des personnes atteintes de l’ostéopétrose infantile s’épaissit, entraînant des conséquences suivantes : </p><ul><li>la compression de certains nerfs, provoquant des problèmes de vision et l’affaiblissement des muscles facials;</li><li>des sinus nasaux étroits, provoquant la congestion nasale. </li></ul><p>L’épaississement des os de l’oreille peut provoquer la compression des nerfs, entraînant une déficience auditive.</p><h3>Niveau de calcium et de parathormone</h3><p>Les enfants atteints de l’ostéopétrose infantile ont du niveau plus bas que d’habitude du calcium et de la parathormone dans leur sang. Si ces niveaux ne sont bien gérés, ceci pourrait engendrer parfois de l’irritabilité accrue et des crises. Souvent, ces crises s’avèrent être la première signe de l’ostéopétrose infantile.</p><h3>Espérance de vie</h3><p>Suite à des échecs en matière de moelle osseuse et à des infections récurrentes, certains bébés atteints de l’ostéopétrose infantile peuvent décéder avant qu’ils n’atteignent l’âge de deux ans. Sans traitement, la plupart des patients meurent avant l’âge de dix ans. La transplantation des cellules souches hématopoïétiques (voir ci-dessous) est le traitement le plus prometteur de la survie à long terme. </p><h2>Ressources et soutien</h2><p>Les organisations et les sites suivants peuvent vous offrir des renseignements détaillés, du soutien, ainsi que du contact avec d’autres personnes touchées et leur famille.</p><h3>Osteopetrosis Support Trust</h3><p> <a href="https://www.osteopetrosis-support-trust.org.uk/">www.osteopetrosis-support-trust.org.uk</a> (en anglais seulement)</p><h3>National Institute of Arthritis and Musculoskeletal and Skin Diseases​​</h3><p> <a href="https://www.niams.nih.gov/">www.niams.nih.gov</a> (en anglais seulement)</p><h3>The Paget Foundation​​</h3><p> <a href="http://www.iofbonehealth.org/national-societies/1284">www.iofbonehealth.org/national-societies/1284</a> (en anglais seulement)</p>

 

 

 

 

Infantile osteopetrosis873.000000000000Infantile osteopetrosisInfantile osteopetrosisIEnglishGeneticsChild (0-12 years);Teen (13-18 years)BodyBonesConditions and diseasesCaregivers Adult (19+)NA2011-09-01T04:00:00Z10.300000000000044.90000000000001627.00000000000Health (A-Z) - ConditionsHealth A-Z<p>Information for parents about infantile osteopetrosis, a rare genetic condition that may cause fractures, short stature (height), recurrent infections, hearing loss and vision problems.</p><h2>What is infantile osteopetrosis?</h2> <p>Infantile osteopetrosis (say: oss-tee-oh-peh-TRO-siss) is a genetic condition that may result in: </p> <ul> <li>fractures</li> <li>short stature (height)</li> <li>recurrent infections</li> <li>hearing loss</li> <li>vision problems</li> </ul> <p>Other names you may hear for this condition are early onset osteopetrosis and malignant infantile osteopetrosis. </p> <p>This condition is quite rare and is believed to affect about one in 200,000 people. </p> <p>There are several different forms of osteopetrosis: infantile, juvenile and adult onset. In general, infantile osteopetrosis is the most severe form, while adult-onset osteopetrosis is the mildest form.<br></p><h2>Key points</h2> <ul> <li>Infantile osteopetrosis is a genetic condition that may result in fractures, short stature, recurrent infections, hearing loss and vision problems.</li> <li>Children with infantile osteopetrosis need to be followed carefully by a health care team made up of different specialists because they may develop health problems.</li> <li>Genetic counselling can help families understand infantile osteopetrosis, the options for managing it, and the chances that other children will also be affected.</li> </ul><h2>Osteopetrosis is a genetic condition</h2><p>Genetic means related to genes. Each of us inherits our genes from our parents. They provide our bodies with instructions that influence our health, looks and behaviour. In general, each person has two copies of every gene. </p><p>Infantile osteopetrosis is caused by a mutation (change) in each copy of a gene. One mutation is inherited from the mother and the other from the father. To date, there are several genes known to cause infantile osteopetrosis, including CLCN7, OSTM1, TCIRG1, TNFSF11, PLEKHM1 and TNFRSF11A. </p><p>Infantile osteopetrosis is inherited in an autosomal recessive pattern. This means that:</p><ul><li>A person with infantile osteopetrosis has a mutation in each copy of the gene.</li><li>Each parent carries a mutation in one copy of the gene. The other copy of the gene works normally and because of this, the parent does not show signs and symptoms of infantile osteopetrosis. This person is called a carrier of infantile osteopetrosis.</li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Inheritance of infantile osteopetrosis</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Inheritance_MED_ILL_EN.jpg" alt="Chromosome distribution from parents each carrying a gene with a mutation" /> <figcaption class="asset-image-caption">Infantile osteopetrosis is caused by mutations in both copies of one of the genes known to cause this condition. In this example, both healthy parents are carriers of the gene with a mutation. Their baby can inherit one of the following gene combinations: one, two or no copies of the gene with a mutation. If a baby inherits no copies or just one copy of the gene with a mutation, the baby will not have infantile osteopetrosis. It is only when a baby inherits two copies of the gene with a mutation that the baby will have infantile osteopetrosis.</figcaption> </figure> <p>To learn more about genetics, visit: <a href="/Article?contentid=343&language=English">Genetic counselling</a>.</p><h2>Diagnosing infantile osteopetrosis</h2><p>A diagnosis of infantile osteopetrosis is made on the basis of physical examination and X-ray findings. X-rays shows thickening and increased density of bones and bone-within-bone appearance. The diagnosis may be confirmed by DNA testing (blood test).</p><h3>Infantile osteopetrosis can be diagnosed before birth</h3><p>Before birth, infantile osteopetrosis can be diagnosed by testing DNA taken from the fetus. This can be obtained in one of the following ways:</p><ul><li>by amniocentesis after the 15th week of pregnancy </li><li>by chorionic villus sampling (CVS) between the 11th and 14th week of pregnancy</li></ul><p>These methods are used for high-risk pregnancies, for instance if the parents have another child diagnosed with infantile osteopetrosis. </p><p>To be eligible for this testing, the mutations in the gene responsible for causing infantile osteopetrosis must be known. This means that the child with the condition must have genetic testing.<br></p><p>Infantile osteopetrosis may also be diagnosed before birth using ultrasound as early as 14 weeks' gestation. However, it is possible to have a normal ultrasound and still have a baby with infantile osteopetrosis. </p> <figure class="asset-c-100"> <span class="asset-image-title">X-ray of healthy vs. infantile osteopetrotic thigh bones</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Xray_MED_ILL_EN.png" alt="X-ray of thighs with healthy bone thickness and density and x-ray of thighs with increased bone thickness and density" /> <figcaption class="asset-image-caption">The thigh bones in the right X-ray show the effects of infantile osteopetrosis. The bones are thicker and have a higher bone density making them appear whiter on the X-ray. </figcaption> </figure><h2>Treatment of infantile osteopetrosis</h2><p>Children with infantile osteopetrosis need attentive, informed care from their parents and health-care providers. </p><p>The goals of treatment are:</p><ul><li>to help children with infantile osteopetrosis adapt socially and physically</li><li>to treat the symptoms</li></ul><h3>Transplantation of hematopoietic stem cells</h3> <p>The most effective treatment option available for infantile osteopetrosis is the transplantation of hematopoietic stem cells. These are the blood stem cells that come from the bone marrow or blood. It is a life-saving procedure with some risks. When successful, it prevents the progression of symptoms and improves bone health. Other problems like vision loss and dental and orthopaedic problems can still happen. </p><p>For more information, please see the <a href="/Article?contentid=2477&language=English">Blood and Marrow Transplant Resource Centre</a> on AboutKidsHealth.ca.</p><h3>Calcium supplements</h3><p>People with infantile osteopetrosis need to have the calcium levels in their blood and urine monitored. If your child's calcium levels are low, your child will need supplements. </p><h3>Transfusions</h3><p>Your child should have a complete blood count at least once every year. Depending on the levels, your child may need transfusions of red blood cells and platelets. </p><p>For more information, please see the <a href="/Article?contentid=1107&language=English">blood transfusion</a> and <a href="/Article?contentid=32&language=English">blood donation</a> articles on AboutKidsHealth.ca.</p> <h3>Treatment of infections</h3><p>If your child often has infections, your child may need antibiotics. </p><h3>Treatment of vision problems</h3><p>Your child should have an eye examination at least once a year. Children with vision problems may need surgery to release the compression of the optic nerve. </p><h3>Treatment of fractures</h3><p>Recurrent fractures need management by an orthopaedic surgeon. Special attention is needed because the fracture may take a long time to heal. Patients may need medication for joint pains. </p><h3>Treatment of dental problems</h3><p>Children with osteopetrosis are more likely to have dental problems like abscesses, cysts and teeth that take longer to come in. Your child should see a dentist regularly.</p><h2>How infantile osteopetrosis affects the body</h2><h3>Bone and dental problems</h3><p>Osteopetrosis is a disorder of bone development in which the bones become thickened. Normally, small areas of bone are constantly being broken down by special cells called osteoclasts, then made again by cells called osteoblasts. This is called bone remodeling, and it helps keep the bones healthy.</p> <figure class="asset-c-100"> <span class="asset-image-title">Bone remodeling cells</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_bone_cells_MED_ILL_EN.jpg" alt="Osteoclast and osteoblast on bone" /> <figcaption class="asset-image-caption">Within our bones are special cells that constantly break down bone and build new bone. Osteoclasts break down bone and osteoblasts make new bone.</figcaption> </figure> <p>In osteopetrosis, the cells that break down bone (osteoclasts) do not work properly, so there is an imbalance between these two functions. This leads to the bones becoming thicker and not as healthy. This can lead to: </p><ul><li>bone fractures </li><li>less overall bone growth, causing short stature</li><li>a thicker skull bone, which may cause teeth to come out later than expected</li><li>larger head size</li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Osteopetrotic bone</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_bone_cycle_MED_ILL_EN.jpg" alt="Osteopetrotic bone with abnormal osteoclasts compared to a healthy bone" /> <figcaption class="asset-image-caption">Normally, our bones are constantly being broken down by osteoclasts and made again by osteoblasts. In osteopetrosis, the osteoclasts are abnormal and cannot break down bone but osteoblasts continue to make new bone. This imbalance results in thicker bones that are not as healthy.</figcaption> </figure> <h3>Problems with bone marrow and blood cells </h3><p>Bone marrow makes new blood cells. It is found inside the bones. In people with infantile osteopetrosis, because the cells that break down bone do not work properly, the space where the bone marrow is found is smaller or even missing. This means there is less bone marrow, so fewer blood cells are made. This can lead to:</p><ul><li>Anemia because of low red blood cells. Symptoms of anemia include pale skin and lack of energy.</li><li>Bleeding problems because of low platelets. Platelets are blood cells needed for clotting to help stop bleeding.</li><li>Many infections due to low white blood cells. White blood cells are needed to fight infections. </li></ul><h3>Problems due to thickening of skull bones</h3><p>The skull bone of people with infantile osteopetrosis is thickened, which can lead to: </p><ul><li>compression of some nerves, causing vision problems and weakness of facial muscles </li><li>narrow nasal sinus, causing chronic nasal congestion</li></ul><p>Thickening of the bones of the ear can cause compression of the nerves, resulting in hearing loss.</p><h3>Calcium and parathyroid levels</h3><p>Children with infantile osteopetrosis have lower levels of calcium and parathyroid hormone in their blood than normal. This may sometimes lead to increased irritability and seizures if it is not managed. These seizures are often the first sign of infantile osteopetrosis. </p><h3>Life expectancy</h3><p>With bone marrow failure and recurrent infections, some babies with infantile osteopetrosis may die before two years of age. Without treatment, most die by the age of ten. Transplantation of hematopoietic stem cells (see below) is the most promising treatment for long-term survival. <br></p><h2>Coping with infantile osteopetrosis</h2> <p>Children with infantile osteopetrosis must be followed carefully by a health care team made up of different specialists. Speak to your health care team if you need help or if you are having trouble coping. Dealing with a child with infantile osteopetrosis can be emotionally difficult.</p> <p>In general, children with visible differences are more likely to have difficulties in school and society. Because of the risk of fractures, your child should avoid high-risk activities and high-impact sports. Encourage your child to participate in activities with other children the same age. As well, try to physically adapt your child's surroundings to support your child and encourage independence.</p><h2>Genetic counselling for infantile osteopetrosis</h2> <p>Children with infantile osteopetrosis and their families should consider assessment by a geneticist and genetic counsellor. They can help with the following:</p> <ul> <li>confirming the diagnosis </li> <li>discussing the natural history of the disease</li> <li>evaluating the risk that future children will also be affected</li> <li>discussing available options for managing the disease</li> </ul><h2>Resources and support</h2><p>The following organizations and sites can offer more information, support and contact with other affected individuals and their families.</p><h3>The OsteoPETrosis Society (OPETS)</h3><p> <a href="http://www.osteopetrosis.org/">www.osteopetrosis.org</a>.</p><h3>Osteopetrosis Support Trust</h3><p> <a href="https://www.osteopetrosis-support-trust.org.uk/">www.osteopetrosis-support-trust.org.uk</a>.</p><h3>National Institute of Arthritis and Musculoskeletal and Skin Diseases</h3><p> <a href="https://www.niams.nih.gov/">www.niams.nih.gov</a>.</p><h3>The Paget Foundation</h3><p> <a href="https://www.iofbonehealth.org/national-societies/1284">www.iofbonehealth.org/national-societies/1284</a>.</p>https://assets.aboutkidshealth.ca/akhassets/Infantile_osteopetrosis_Xray_MED_ILL_EN.pngInfantile osteopetrosisFalse

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