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Hereditary multiple exostoses (HME)HHereditary multiple exostoses (HME)Hereditary multiple exostoses (HME)EnglishGeneticsChild (0-12 years);Teen (13-18 years)Back;Pelvis;Arm;LegsBonesConditions and diseasesCaregivers Adult (19+)NA2011-09-01T04:00:00ZLucie Dupuis, MSc, MS, CGC;Ayeshah Chaudhry, MBBS;Roberto Mendoza-Londono, MD, MS, FACMG, FCCMG9.0000000000000057.00000000000001387.00000000000Health (A-Z) - ConditionsHealth A-Z<p>Information for parents about hereditary multiple exostoses, a genetic condition that causes growths (bumps) on the bones. The growths begin in early childhood.</p><h2>What is hereditary multiple exostoses?</h2> <p>Hereditary multiple exostoses (say: ex-oh-STO-sees), or HME, is a genetic condition that affects bone development. Exostoses are bony growths. People with HME develop these bony growths on the ends of long bones and also on some flat bones such as the shoulder blade (scapula) and the pelvis. These growths typically develop during childhood and adolescence.</p> <p>Another name you may hear for this condition is hereditary osteochondromas. It affects about one in 50,000 people worldwide.</p><h2>Key points</h2> <ul> <li>HME is a genetic condition where exostoses (bony growths) grow on certain bones during childhood and adolescence.</li> <li>Children with HME need to be followed carefully by a health care team if they have symptoms.</li> <li>There is a less than 1% lifetime risk for an exostosis to become cancerous.</li> <li>Genetic counselling can help families understand HME, the options for managing it, and the chances that other children will also be affected.</li> </ul><h2>How hereditary multiple exostoses affects the body</h2> <figure><span class="asset-image-title">Bones affected by hereditary multiple exostoses</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_affected_bones_MED_ILL_EN.jpg" alt="" /> </figure> <h3>Bone problems</h3><p>People with HME have many exostoses that grow at the surface of a number of bones, such as the long bones of the arms and legs, ribs, vertebrae and hipbones. You can sometimes feel them under the skin. The exostoses can sometimes be painful.</p><p>The number and the size of the exostoses vary from person to person and can be different even between parent and child. New exostoses do not grow after someone's bones have matured. However, existing exostoses can grow slowly over the years.</p><h3>Height and body shape</h3><p>The exostoses can sometimes lead to shortening and bowing of long bones and joint problems. Shortening and bowing of the long bones can sometimes lead to one leg being shorter than another.</p><p>People with HME have normal intelligence.</p><h2>HME is a genetic disorder</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 behavior. In general, each person has two copies of every gene. One copy is inherited from the mother and the other from the father. </p><p>HME occurs as a result of a mutation (change) in one copy of the EXT1 or the EXT2 gene.</p><ul><li>In about 10% of people with HME, this is a new mutation, meaning neither parent has the disease.</li><li>However, in about 90% of people with HME, the mutation is inherited (passed on) from one of the parents.</li></ul><p>HME is inherited as an autosomal dominant condition. This means that: </p><ul><li>Only one copy of the gene (either EXT1 or EXT2) has a mutation. In this case, a person will have HME. The other copy of the gene works normally but this is not enough to prevent a person from having HME.</li><li>A person with HME has a 50% chance during each pregnancy of passing this genetic condition on to the child. </li><li>The risk to the sibling (brother or sister) of a person with HME depends if the parent has HME or not.</li></ul> <figure class="asset-c-100"><span class="asset-image-title">Inheritance of HME</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_Inheritance_MED_ILL_EN.jpg" alt="" /><figcaption class="asset-image-caption"> HME is caused by a mutation in either the EXT1 or EXT2 gene. Every person has two copies of each of these genes. A person will have HME if one copy of the gene has a mutation. In this example, the parent with HME has one copy of one of the genes with a mutation and the other has none. If the baby does not inherit the mutation then the baby will not have HME. If the baby inherits the copy of the gene with a mutation, then the baby will have HME. </figcaption> </figure> <p>To learn more about genetics, please visit the <a href="/Article?contentid=343&language=English">genetic counselling</a> article on AboutKidsHealth. </p><h2>HME can be diagnosed before or after birth</h2><p>Before birth, HME 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 HME or one of the parents has HME. </p><p>To be eligible for this testing, the mutations in the gene responsible for causing HME in the family must be known. This means genetic testing (a blood test) must be done on the person in the family with HME.</p><p>HME cannot be diagnosed by ultrasound in pregnancy. This is because the exostoses usually do not start growing until early childhood. </p><p>After birth, the diagnosis of HME is based on X-ray findings. A diagnosis of HME can be confirmed by DNA testing of the EXT1 and EXT2 genes (a blood test).</p> <figure class="asset-c-100"><span class="asset-image-title">X-ray of exostoses</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_xray_MED_ILL_EN.jpg" alt="" /><figcaption class="asset-image-caption">This X-ray shows a lower leg bone with three exostoses (bony growths). Exostoses mainly grow on the ends of long bones. The number and the size of the exostoses vary from person to person. </figcaption> </figure><h2>Treatment of HME</h2> <p>There are no treatments to prevent the growth of exostoses. At this time, treatment is based on each person's symptoms. Children with HME lead fulfilling lives if they receive attentive, informed care from their parents and health-care providers. </p> <h3>Treatment of complications</h3> <p>Pain management, physical therapy and surgery are the treatment options available for the various complications. </p> <ul> <li>Pain should be managed with medication when needed. </li> <li>Painful exostoses that result in compression of a nerve or vessel may be treated by surgery. </li> <li>If exostoses are large or if bone deformities occur, then surgery may also be an option. </li> </ul> <h3>Monitoring for cancer</h3> <p>The most important aspect in the management of HME is monitoring for cancer. Monitoring the size of exostoses in adults, in particular those involving the pelvis or scapula, may help in early detection and treatment. For this reason, it is important to notify a health-care provider if one begins to experience rapid growth of exostoses and increasing pain, especially as an adult.</p> <h3>Treatment of malignant transformation (cancer)</h3> <p>There is less than 1% lifetime risk for an exostosis to become cancerous. In these cases, surgery to remove the exostoses is necessary. The use of radiotherapy and chemotherapy is controversial. Speak to your oncology team for more information about treatment.</p> <h2>Genetic counselling for HME</h2> <p>People with HME 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>Complications of exostoses</h2> <h3>Pain</h3> <p>The most common complication in HME is pain associated with the exostoses. </p> <h3>Cancer risk</h3> <p>There is a small risk for an exostosis to turn malignant (cancerous). This risk is less than 1% over someone's lifetime. </p> <h3>Pressure effects of the exostoses</h3> <p>Depending on the size and location of the exostoses, they may cause one or more of the following effects:</p> <ul> <li>compression of peripheral nerves</li> <li>irritation of overlying muscles and tendons, leading to pain, compression of blood vessels and restriction of joint motion</li> </ul> <h3>Pregnancy and childbirth</h3> <p>Exostoses of pelvic bones may cause a problem in pregnancy and childbirth. There is a slightly higher chance of a Caesarean section for delivery in mothers with HME.</p><h2>Patient resources</h2> <p>The following organizations and sites can offer more information, support, and contact with other affected individuals and their families.</p> <h3>MHE and Me</h3> <p><a href="http://www.mheandme.com/" target="_blank">www.mheandme.com</a></p> <h3>The MHE Research Foundation</h3> <p><a href="http://www.mheresearchfoundation.org/" target="_blank">www.MHEResearchfoundation.org</a></p> <h3>The MHE Coalition</h3> <p><a href="http://www.mhecoalition.org/" target="_blank">www.mhecoalition.org</a></p>
Maladie des exostoses multiplesMMaladie des exostoses multiplesHereditary Multiple Exostoses (HME)FrenchGeneticsChild (0-12 years);Teen (13-18 years)Back;Pelvis;Arm;LegsBonesConditions and diseasesCaregivers Adult (19+)NA2011-09-01T04:00:00ZLucie Dupuis, MSc, MS, CGC;Ayeshah Chaudhry, MBBS;Roberto Mendoza-Londono, MD, MS, FACMG, FCCMGHealth (A-Z) - ConditionsHealth A-Z<p>Information au bénéfice des parents à propos de la maladie des exostoses multiples, une maladie génétique causant des excroissances osseuses (bosses sur les os). Les excroissances apparaissent au cours de la petite enfance.</p><h2>Qu’est-ce que la maladie des exostoses multiples ?</h2><p>La maladie des exostoses (prononcer : ex-oh-sto-ses) multiples est une maladie génétique qui affecte le développement osseux. Les exostoses sont des excroissances osseuses. Les personnes atteintes de la maladie des exostoses multiples développent des excroissances osseuses au bout des os longs et également sur certains os plats tels l’omoplate et le bassin. Ces excroissances se développent habituellement au cours de l’enfance et l’adolescence.</p><p>On appelle également cette maladie l’ostéochondrome héréditaire qui affecte une personne sur 50 000 mondialement.</p><h2>À retenir</h2> <ul><li>La maladie des exostoses multiples est caractérisée par le développement d’exostoses (excroissances osseuses) sur certains os au cours de l’enfance et de l’adolescence.</li><li>Les enfants atteints de la maladie des exostoses multiples doivent être suivis de près par une équipe de soins de santé s’ils ont des symptômes.</li><li>Le risque qu’une exostose devienne cancéreuse est de moins de 1 % sur toute la vie.</li><li>La consultation génétique peut aider les familles à comprendre la maladie des exostoses multiples, les options disponibles pour contrôler la maladie et les risques d’avoir un autre enfant atteint.</li></ul><h2>Quels sont les impacts de la maladie des exostoses multiples sur le corps ?</h2> <figure><span class="asset-image-title">Os atteints de la maladie des exostoses multiples</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_affected_bones_MED_ILL_FR.jpg" alt="" /> </figure> <h3>Troubles osseux</h3><p>Les personnes atteintes de la maladie des exostoses multiples peuvent avoir des exostoses qui grossissent à la surface de plusieurs os, en particulier les os longs des bras et des jambes, les côtes, les vertèbres et les os du bassin. Vous pouvez parfois les sentir sous la peau. Les exostoses peuvent parfois être douloureuses.</p><p>Le nombre et la grosseur des exostoses peuvent varier d’une personne à l’autre et peuvent être différents entre les enfants et les parents. De nouvelles exostoses ne peuvent pas grossir après l’arrêt de la croissance osseuse. Par contre, les exostoses existantes peuvent grossir lentement avec le temps.</p><h3>La grandeur et la morphologie</h3><p>Les exostoses peuvent parfois mener à un raccourcissement et une courbure des os longs ainsi qu’à certains problèmes des articulations. Le raccourcissement et la courbure des os longs peuvent parfois mener à ce qu’une jambe soit plus courte que l’autre.</p><p>Les personnes atteintes de la maladie des exostoses multiples ont une intelligence normale.</p><h2>La maladie des exostoses multiples est une maladie génétique</h2><p>Génétique signifie en lien avec les gènes. Nous héritons nos gènes de nos parents. Les gènes fournissent les instructions corporelles qui régissent notre santé, notre apparence et notre comportement. En général, chaque personne possède deux copies de chaque gène. </p><p>Une copie vient de la mère et l’autre copie vient du père. La maladie des exostoses multiples est causée par une mutation (un changement) dans une copie des gènes EXT1 ou EXT2.</p><ul><li>Dans environ 10 % des cas, il s’agit d’une nouvelle mutation, car aucun des deux parents n’est atteint.</li><li>Par contre, dans environ 90 % des cas, la mutation est héritée (donnée) d’un des parents.</li></ul><p>La maladie des exostoses multiples est une maladie héréditaire autosomique dominante. Cela signifie que :</p><ul><li>Une seule copie du gène (soit EXT1 ou EXT2) a une mutation. Si c’est le cas, la personne sera atteinte de la maladie des exostoses multiples. L’autre copie du gène fonctionne normalement, mais cela ne prévient pas le développement de la maladie chez la personne atteinte.</li><li>La personne atteinte de la maladie des exostoses multiples a 50 % des chances de donner la mutation à l’enfant au cours d’une grossesse.</li><li>Le risque pour le frère ou la sœur d’une personne atteinte de la maladie des exostoses multiples de développer la maladie est différent si le parent est atteint ou normal.<br></li></ul> <figure class="asset-c-100"> <span class="asset-image-title">Hérédité de la maladie des exostoses multiples</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_Inheritance_MED_ILL_FR.jpg" alt="" /><figcaption class="asset-image-caption">La maladie des exostoses multiples est causée par une mutation d’un des gènes EXT1 ou EXT2. Chaque personne possède deux copies de ces deux gènes. Une personne sera atteinte de la maladie des exostoses multiples s’il y a une mutation dans une copie d’un des deux gènes. Dans cet exemple, le parent atteint de la maladie des exostoses multiples possède une copie mutée d’un des deux gènes et l’autre parent n’en a pas. Si le bébé n’hérite pas de la mutation, alors il n’aura pas la maladie des exostoses multiples. Si le bébé hérite de la copie mutée du gène, il sera atteint de la maladie des exostoses multiples.</figcaption> </figure> <p>Pour de plus amples renseignements sur la génétique, veuillez lire <a href="/Article?contentid=343&language=English">Consultation génétique</a>. </p><h2>Le diagnostic de la maladie des exostoses multiples peut être effectué avant et après la naissance</h2><p>Le diagnostic de la maladie des exostoses multiples peut être effectué avant la naissance par l’analyse de l’ADN du fœtus, qui peut être obtenu :</p><ul><li>par amniocentèse après la quinzième semaine de grossesse;</li><li>par choriocentèse entre la 11e et la 14e semaine de grossesse.</li></ul><p>Ces méthodes sont utilisées dans les cas de grossesse à haut risque, par exemple lorsque les parents ont un autre enfant atteint de la maladie des exostoses multiples ou qu’un des parents est atteint. La mutation du gène responsable de la maladie des exostoses multiples dans la famille doit être connue pour que l’enfant soit admissible au dépistage génétique. Ceci est effectué par un test sanguin sur le membre de la famille atteint par la maladie. </p><p>Le diagnostic de la maladie des exostoses multiples ne peut pas être fait à l’aide de l’échographie durant la grossesse, car les exostoses amorcent leur croissance habituellement au cours de la petite enfance.</p><p>Le diagnostic de la maladie des exostoses multiples est effectué après la naissance par des évaluations radiographiques. Le diagnostic de la maladie peut être confirmé par un test d’ADN sur les gènes EXT1 et EXT2 (test sanguin).</p> <figure class="asset-c-100"><span class="asset-image-title">Radiographie des exostoses</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_xray_MED_ILL_FR.jpg" alt="" /><figcaption class="asset-image-caption">Cette radiographie montre la partie inférieure d’une jambe avec trois exostoses (excroissances osseuses). Les exostoses poussent principalement à l’extrémité des os longs. Le nombre et la grosseur des exostoses peuvent être différents d’une personne à l’autre.</figcaption> </figure><h2>Le traitement de la maladie des exostoses multiples</h2><p>Il n’existe pas de traitement pour prévenir la croissance des exostoses. Jusqu’à maintenant, le traitement dépend des symptômes de chacun des patients. Les enfants atteints de la maladie des exostoses multiples s’épanouissent pleinement s’ils reçoivent des soins appropriés et éclairés de la part de leurs parents et de leur fournisseur de soins de santé.</p><h3>Le traitement des complications</h3><p>Les traitements possibles pour les complications de la maladie sont la gestion de la douleur, la physiothérapie et l’opération chirurgicale.</p><ul><li>La douleur devrait être contrôlée avec des médicaments au besoin.</li><li>Les exostoses douloureuses qui compressent un nerf ou un vaisseau sanguin peuvent être enlevées lors une opération chirurgicale.</li><li>Cette dernière peut aussi être envisagée si les exostoses sont grosses et déforment les os.</li></ul><h3>Dépistage du cancer</h3><p>L’aspect le plus important du contrôle de la maladie des exostoses multiples est le dépistage du cancer. L’évaluation de la taille des exostoses chez les adultes, plus particulièrement celles localisées dans la région pelvienne ou les omoplates, peut aider à la détection précoce et au traitement. C’est pourquoi il est important d’aviser son fournisseur de soins de santé si une exostose grossit rapidement ou devient plus douloureuse, plus particulièrement chez l’adulte.</p><h3>Le traitement des transformations malignes (cancer)</h3><p>Le risque qu’une exostose devienne cancéreuse est de moins de 1 % pour toute la vie. De tels cas nécessitent l’ablation de l’exostose lors d’une opération chirurgicale. L’utilisation de la radiothérapie ou de la chimiothérapie est controversée. Consultez votre équipe en oncologie pour de plus amples renseignements sur le traitement.</p><h2>Consultation génétique à propos de la maladie des exostoses multiples</h2><p>Les personnes atteintes de la maladie des exostoses multiples et leurs familles devraient considérer une évaluation par un généticien ou un conseiller en génétique. Ils peuvent vous aider dans les situations suivantes pour :</p><ul><li>confirmer un diagnostic;</li><li>discuter de l’histoire naturelle de la maladie;</li><li>évaluer les risques qu’un enfant à venir soit affecté;</li><li>discuter des options disponibles pour contrôler la maladie.</li></ul><h2>Les complications des exostoses</h2><h3>La douleur</h3><p>La complication la plus fréquente de la maladie des exostoses multiples est la douleur associée aux exostoses.</p><h3>Risques de cancer</h3> <p>Il existe un faible risque selon lequel une exostose deviendrait maligne (cancéreuse). Ce risque est de moins de 1 % au cours de la vie.</p><h3>Les effets de la pression sur les exostoses </h3><p>Les exostoses peuvent avoir différentes conséquences en fonction de leur taille et de leur localisation. Ils peuvent :</p><ul><li>comprimer des nerfs périphériques;</li><li>irriter les muscles et les tendons au-dessus de l’os, causant de la douleur, une compression des vaisseaux sanguins et limitant l’amplitude de mouvement des articulations.</li></ul><h3>Grossesse et accouchement</h3><p>Les exostoses sur les os pelviens peuvent être problématiques au cours de la grossesse et durant l’accouchement. Il y a un risque légèrement plus élevé d’un accouchement par césarienne chez les mères atteintes de la maladie des exostoses multiples.</p><h2>Ressources aux patients</h2><p>Les organismes suivants et les sites internet peuvent vous offrir plus d’information, de soutien et vous mettre en relation avec d’autres individus atteints et leurs familles.</p><h3>MHE and Me</h3><p> <a href="http://www.mheandme.com/" target="_blank">www.mheandme.com</a> (en anglais seulement)</p><h3>The MHE Research Foundation</h3><p> <a href="http://www.mheresearchfoundation.org/" target="_blank">www.MHEResearchfoundation.org</a> (en anglais seulement)</p><h3>The MHE Coalition</h3><p> <a href="http://www.mhecoalition.org/" target="_blank">www.mhecoalition.org</a> (en anglais seulement)</p>

 

 

Hereditary multiple exostoses (HME)874.000000000000Hereditary multiple exostoses (HME)Hereditary multiple exostoses (HME)HEnglishGeneticsChild (0-12 years);Teen (13-18 years)Back;Pelvis;Arm;LegsBonesConditions and diseasesCaregivers Adult (19+)NA2011-09-01T04:00:00ZLucie Dupuis, MSc, MS, CGC;Ayeshah Chaudhry, MBBS;Roberto Mendoza-Londono, MD, MS, FACMG, FCCMG9.0000000000000057.00000000000001387.00000000000Health (A-Z) - ConditionsHealth A-Z<p>Information for parents about hereditary multiple exostoses, a genetic condition that causes growths (bumps) on the bones. The growths begin in early childhood.</p><h2>What is hereditary multiple exostoses?</h2> <p>Hereditary multiple exostoses (say: ex-oh-STO-sees), or HME, is a genetic condition that affects bone development. Exostoses are bony growths. People with HME develop these bony growths on the ends of long bones and also on some flat bones such as the shoulder blade (scapula) and the pelvis. These growths typically develop during childhood and adolescence.</p> <p>Another name you may hear for this condition is hereditary osteochondromas. It affects about one in 50,000 people worldwide.</p><h2>Key points</h2> <ul> <li>HME is a genetic condition where exostoses (bony growths) grow on certain bones during childhood and adolescence.</li> <li>Children with HME need to be followed carefully by a health care team if they have symptoms.</li> <li>There is a less than 1% lifetime risk for an exostosis to become cancerous.</li> <li>Genetic counselling can help families understand HME, the options for managing it, and the chances that other children will also be affected.</li> </ul><h2>How hereditary multiple exostoses affects the body</h2> <figure><span class="asset-image-title">Bones affected by hereditary multiple exostoses</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_affected_bones_MED_ILL_EN.jpg" alt="" /> </figure> <h3>Bone problems</h3><p>People with HME have many exostoses that grow at the surface of a number of bones, such as the long bones of the arms and legs, ribs, vertebrae and hipbones. You can sometimes feel them under the skin. The exostoses can sometimes be painful.</p><p>The number and the size of the exostoses vary from person to person and can be different even between parent and child. New exostoses do not grow after someone's bones have matured. However, existing exostoses can grow slowly over the years.</p><h3>Height and body shape</h3><p>The exostoses can sometimes lead to shortening and bowing of long bones and joint problems. Shortening and bowing of the long bones can sometimes lead to one leg being shorter than another.</p><p>People with HME have normal intelligence.</p><h2>HME is a genetic disorder</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 behavior. In general, each person has two copies of every gene. One copy is inherited from the mother and the other from the father. </p><p>HME occurs as a result of a mutation (change) in one copy of the EXT1 or the EXT2 gene.</p><ul><li>In about 10% of people with HME, this is a new mutation, meaning neither parent has the disease.</li><li>However, in about 90% of people with HME, the mutation is inherited (passed on) from one of the parents.</li></ul><p>HME is inherited as an autosomal dominant condition. This means that: </p><ul><li>Only one copy of the gene (either EXT1 or EXT2) has a mutation. In this case, a person will have HME. The other copy of the gene works normally but this is not enough to prevent a person from having HME.</li><li>A person with HME has a 50% chance during each pregnancy of passing this genetic condition on to the child. </li><li>The risk to the sibling (brother or sister) of a person with HME depends if the parent has HME or not.</li></ul> <figure class="asset-c-100"><span class="asset-image-title">Inheritance of HME</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_Inheritance_MED_ILL_EN.jpg" alt="" /><figcaption class="asset-image-caption"> HME is caused by a mutation in either the EXT1 or EXT2 gene. Every person has two copies of each of these genes. A person will have HME if one copy of the gene has a mutation. In this example, the parent with HME has one copy of one of the genes with a mutation and the other has none. If the baby does not inherit the mutation then the baby will not have HME. If the baby inherits the copy of the gene with a mutation, then the baby will have HME. </figcaption> </figure> <p>To learn more about genetics, please visit the <a href="/Article?contentid=343&language=English">genetic counselling</a> article on AboutKidsHealth. </p><h2>Course of the disease</h2> <p>The growth of the exostoses begins in early childhood. The average age of diagnosis is three years. Nearly all people with HME are diagnosed before 12 years of age. </p> <p>Growth of the exostoses slows down in adolescence and there are no new exostoses in adulthood.</p> <p>Most people with HME lead active and healthy lives.</p><h2>HME can be diagnosed before or after birth</h2><p>Before birth, HME 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 HME or one of the parents has HME. </p><p>To be eligible for this testing, the mutations in the gene responsible for causing HME in the family must be known. This means genetic testing (a blood test) must be done on the person in the family with HME.</p><p>HME cannot be diagnosed by ultrasound in pregnancy. This is because the exostoses usually do not start growing until early childhood. </p><p>After birth, the diagnosis of HME is based on X-ray findings. A diagnosis of HME can be confirmed by DNA testing of the EXT1 and EXT2 genes (a blood test).</p> <figure class="asset-c-100"><span class="asset-image-title">X-ray of exostoses</span><img src="https://assets.aboutkidshealth.ca/akhassets/HME_xray_MED_ILL_EN.jpg" alt="" /><figcaption class="asset-image-caption">This X-ray shows a lower leg bone with three exostoses (bony growths). Exostoses mainly grow on the ends of long bones. The number and the size of the exostoses vary from person to person. </figcaption> </figure><h2>Treatment of HME</h2> <p>There are no treatments to prevent the growth of exostoses. At this time, treatment is based on each person's symptoms. Children with HME lead fulfilling lives if they receive attentive, informed care from their parents and health-care providers. </p> <h3>Treatment of complications</h3> <p>Pain management, physical therapy and surgery are the treatment options available for the various complications. </p> <ul> <li>Pain should be managed with medication when needed. </li> <li>Painful exostoses that result in compression of a nerve or vessel may be treated by surgery. </li> <li>If exostoses are large or if bone deformities occur, then surgery may also be an option. </li> </ul> <h3>Monitoring for cancer</h3> <p>The most important aspect in the management of HME is monitoring for cancer. Monitoring the size of exostoses in adults, in particular those involving the pelvis or scapula, may help in early detection and treatment. For this reason, it is important to notify a health-care provider if one begins to experience rapid growth of exostoses and increasing pain, especially as an adult.</p> <h3>Treatment of malignant transformation (cancer)</h3> <p>There is less than 1% lifetime risk for an exostosis to become cancerous. In these cases, surgery to remove the exostoses is necessary. The use of radiotherapy and chemotherapy is controversial. Speak to your oncology team for more information about treatment.</p> <h2>Genetic counselling for HME</h2> <p>People with HME 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>Complications of exostoses</h2> <h3>Pain</h3> <p>The most common complication in HME is pain associated with the exostoses. </p> <h3>Cancer risk</h3> <p>There is a small risk for an exostosis to turn malignant (cancerous). This risk is less than 1% over someone's lifetime. </p> <h3>Pressure effects of the exostoses</h3> <p>Depending on the size and location of the exostoses, they may cause one or more of the following effects:</p> <ul> <li>compression of peripheral nerves</li> <li>irritation of overlying muscles and tendons, leading to pain, compression of blood vessels and restriction of joint motion</li> </ul> <h3>Pregnancy and childbirth</h3> <p>Exostoses of pelvic bones may cause a problem in pregnancy and childbirth. There is a slightly higher chance of a Caesarean section for delivery in mothers with HME.</p><h2>Coping with HME</h2> <p>In general, children with visible differences are more likely to have difficulties in school and society. Because of the risk of pain associated with exostoses, your child should avoid activities that increase this pain. These activities are different for every child. 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> <p>Children with HME must be followed carefully by a health care team if they have symptoms. Speak to your health care team if you need help or if you are having trouble coping.</p><h2>Patient resources</h2> <p>The following organizations and sites can offer more information, support, and contact with other affected individuals and their families.</p> <h3>MHE and Me</h3> <p><a href="http://www.mheandme.com/" target="_blank">www.mheandme.com</a></p> <h3>The MHE Research Foundation</h3> <p><a href="http://www.mheresearchfoundation.org/" target="_blank">www.MHEResearchfoundation.org</a></p> <h3>The MHE Coalition</h3> <p><a href="http://www.mhecoalition.org/" target="_blank">www.mhecoalition.org</a></p>https://assets.aboutkidshealth.ca/akhassets/HME_affected_bones_MED_ILL_EN.jpgHereditary multiple exostoses (HME)False

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