Hereditary spherocytosis: GeneticsHHereditary spherocytosis: GeneticsHereditary spherocytosis: GeneticsEnglishGenetics;HaematologyChild (0-12 years);Teen (13-18 years)Gall Bladder;SpleenGallbladderConditions and diseasesAdult (19+) CaregiversNA2019-01-02T05:00:00Z9.6000000000000050.3000000000000550.000000000000Health (A-Z) - ConditionsHealth A-Z<p>Hereditary spherocytosis is a genetic condition. In most cases it is inherited from a parent. Learn how HS is inherited and what happens in a de novo mutation.</p><h2>What is hereditary spherocytosis?</h2><p><a href="/Article?contentid=3630&language=English">Hereditary spherocytosis (HS)</a> is a genetic blood disorder of the red blood cells. Red blood cells contain hemoglobin, which is the molecule that carries oxygen from the lungs to the rest of the body.</p><p>Red blood cells are usually shaped like a disk, with a depressed centre, like a donut without a hole. In HS, most red blood cells are circular and shaped like spheres. These are called spherocytes.</p><p>HS is the most common form of inherited hemolytic anemia. “Hemolytic” refers to hemolysis, which is the breakdown of the red blood cells. Anemia is a lack of either hemoglobin or red blood cells in the body.</p><h2>Key points</h2><ul><li>Hereditary spherocytosis (HS) is an inherited blood disorder of the red blood cells.</li><li>HS affects approximately 1 in 2000-3000 people. The number of cases may be higher as mild cases can go undiagnosed.</li><li>A person can inherit HS through an autosomal dominant inheritance, autosomal recessive inheritance, or a de novo mutation. A de novo mutation occurs by chance and is not inherited from either parent.</li></ul><h2>How is hereditary spherocytosis inherited?</h2><p>In most cases, HS is an inherited genetic condition, which means that the genes involved in HS are typically passed down from one or both parents to their children. </p><p>Although HS occurs in all racial groups, it is more common in people of Northern European descent. HS affects approximately 1 in 2000-3000 people. The number of cases of HS may be underestimated because mild cases can go undiagnosed. </p><p>A gene is a section of DNA that gives specific instructions to a cell. Most of the time, the instruction is a recipe for making a protein. A change (mutation) in a gene results in a protein that cannot function properly. </p><p>In general, each person has two copies of every gene. One copy is inherited from the mother and the other from the father. There are three possible ways a person can inherit HS. </p><h3>Autosomal dominant inheritance </h3><p>Autosomal dominant inheritance occurs when one parent is affected with HS and the other parent is unaffected. One normal gene from the unaffected parent, and one gene with a mutation from the affected parent, are passed down to the child. In autosomal dominant inheritance, only one abnormal copy of the gene is needed to cause disease. A parent affected with HS has a 50% chance of passing the condition on to the child.</p> <figure class="asset-c-80"> <span class="asset-image-title">Autosomal dominant inheritance</span> <img src="https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_dominant_EN.jpg" alt="" /> </figure> <p>Autosomal dominant inheritance occurs in approximately 70% to 80% of HS cases. </p><h3>Autosomal recessive inheritance</h3><p>In autosomal recessive inheritance both copies of the gene passed down to a child are abnormal and result in HS. In this scenario, both copies of the gene need to have a mutation to cause disease. Parents usually show no signs or symptoms of the disease as they typically have one normal copy of the gene and one abnormal copy of the gene (they are known as “carriers”). </p> <figure class="asset-c-80"> <span class="asset-image-title">Autosomal recessive inheritance</span> <img src="https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_recessive_EN.jpg" alt="" /> </figure> <p>Autosomal recessive inheritance occurs in approximately 10% of HS cases.</p><h3>De novo mutation</h3><p>HS can be caused by a new (de novo) mutation that occurred by chance when the baby was conceived. It was not passed down from either parent. </p> <figure class="asset-c-80"> <span class="asset-image-title">De novo mutation</span> <img src="https://assets.aboutkidshealth.ca/akhassets/de_novo_mutation_EN.jpg" alt="" /> </figure> <p>De novo mutations occur in approximately 20% of HS cases, however the exact number of de novo mutations in HS is not known.</p>
Sphérocytose héréditaire : aspects liés à la génétiqueSSphérocytose héréditaire : aspects liés à la génétiqueHereditary spherocytosis: GeneticsFrenchGenetics;HaematologyChild (0-12 years);Teen (13-18 years)Gall Bladder;SpleenGallbladderConditions and diseasesAdult (19+) CaregiversNA2019-01-02T05:00:00Z9.6000000000000050.3000000000000550.000000000000Health (A-Z) - ConditionsHealth A-Z<p>La sphérocytose héréditaire est une maladie génétique transmise par le père ou la mère dans la plupart des cas. Apprenez comment la SH est transmise dans les cas de mutation génétique de novo.</p><h2>Qu’est-ce que la sphérocytose héréditaire? </h2><p>La <a href="/Article?contentid=3630&language=French">sphérocytose héréditaire (SH)</a> est une maladie génétique du sang qui altère les globules rouges. Ces cellules contiennent une molécule, l’hémoglobine, qui transporte l’oxygène depuis les poumons vers le reste de l’organisme.</p><p>Les globules rouges ont en général la forme d’un disque dont le centre est enfoncé comme un beigne, mais sans le trou. Chez les sujets qui souffrent de la maladie, la plupart des globules rouges sont circulaires et sphériques. On les appelle sphérocytes. La SH est la forme la plus courante d’anémie hémolytique héréditaire. Par analogie à l’hémolyse, le processus hémolytique est responsable de la destruction des globules rouges. L’anémie se caractérise par le manque d’hémoglobine ou de globules rouges dans l’organisme.</p><h2>À retenir</h2><ul><li>La sphérocytose héréditaire (SH) est un trouble sanguin héréditaire qui affecte les globules rouges. </li><li>Environ une personne sur 2 000 ou 3 000 en est atteinte. Le nombre de cas de SH pourrait être plus élevé du fait que le nombre de cas légers peut n’avoir jamais fait l’objet d’un diagnostic.</li><li>Une personne peut hériter de la SH par le biais de l’hérédité autosomique dominante, de l’hérédité autosomique récessive ou d’une mutation génétique de novo. Ce dernier mode de transmission est le fruit du hasard et la mutation ne provient ni du père ni de la mère.</li></ul><h2>Comment la sphérocytose héréditaire se transmet-elle?</h2><p>Dans la plupart des cas, la SH est une maladie génétique qui est transmise d’une génération à l’autre, ce qui signifie que les gènes liés à la SH sont d’ordinaire transmis aux enfants par le père, la mère ou les deux. Bien que la SH soit présente dans tous les groupes raciaux, elle est plus courante chez les peuples d’ascendance nord-européenne. Environ une personne sur 2 000 ou 3 000 en est atteinte. Le nombre de cas de SH peut être sous-estimé, car le nombre de cas légers de la maladie peut n’avoir fait l’objet d’aucun diagnostic.</p><p>Un gène est une section de l’ADN qui fournit des instructions précises à une cellule. Une modification (mutation) du gène entraîne un défaut dans une protéine qui, par la suite, ne fonctionnera pas de façon adéquate.</p><p>Chaque personne possède, en général, deux copies de chaque gène. Une copie provient de la mère et l’autre du père. La SH peut se transmettre de trois façons différentes.</p><h3>Hérédité autosomique dominante</h3><p>L’hérédité autosomique dominante survient lorsque l’un des parents souffre de la SH tandis que l’autre parent n’en souffre pas. Le gène normal du parent non atteint de la maladie et le gène portant une mutation qui provient du parent atteint de la maladie sont transmis à l’enfant. Selon l’hérédité autosomique dominante, une seule copie anormale du gène est nécessaire pour que l’enfant soit atteint de la maladie. La probabilité qu’un parent atteint de la SH transmette la maladie à son enfant est de 50 %.</p> <figure class="asset-c-80"><span class="asset-image-title">Hérédité autosomique dominante</span><img src="https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_dominant_FR.jpg" alt="" /> </figure> <p>L’hérédité autosomique dominante est responsable d’environ 70 à 80 % des cas de SH.</p><h3>Hérédité autosomique récessive</h3><p>Selon l’hérédité autosomique récessive, les deux copies du gène transmises à l’enfant sont anormales et induisent la SH. Dans ce scénario, il est nécessaire que les deux copies du gène présentent une mutation pour que la maladie en résulte. Les parents n’ont habituellement aucun symptôme de la maladie, car ils ont d’ordinaire une copie normale et une copie anormale du gène. On dit qu’ils sont « porteurs » de la maladie. </p> <figure class="asset-c-80"><span class="asset-image-title">Hérédité autosomique récessive</span><img src="https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_recessive_FR.jpg" alt="" /> </figure> <p>L’hérédité autosomique récessive est responsable d’environ 10 % des cas de SH.</p><h3>Mutation génétique de novo</h3><p>La SH peut être causée par une mutation génétique inédite (de novo) qui se produit par hasard au moment de la conception du bébé. Elle ne provient ni du père ni de la mère.</p> <figure class="asset-c-80"><span class="asset-image-title">Mutation génétique de novo</span><img src="https://assets.aboutkidshealth.ca/akhassets/de_novo_mutation_FR.jpg" alt="" /> </figure> <p>Les mutations génétiques de novo se produisent dans environ 20 % des cas de SH. Nous ignorons le nombre exact de mutations génétiques de novo qui s’appliquent à la SH.</p>

 

 

 

 

Hereditary spherocytosis: Genetics3631.00000000000Hereditary spherocytosis: GeneticsHereditary spherocytosis: GeneticsHEnglishGenetics;HaematologyChild (0-12 years);Teen (13-18 years)Gall Bladder;SpleenGallbladderConditions and diseasesAdult (19+) CaregiversNA2019-01-02T05:00:00Z9.6000000000000050.3000000000000550.000000000000Health (A-Z) - ConditionsHealth A-Z<p>Hereditary spherocytosis is a genetic condition. In most cases it is inherited from a parent. Learn how HS is inherited and what happens in a de novo mutation.</p><h2>What is hereditary spherocytosis?</h2><p><a href="/Article?contentid=3630&language=English">Hereditary spherocytosis (HS)</a> is a genetic blood disorder of the red blood cells. Red blood cells contain hemoglobin, which is the molecule that carries oxygen from the lungs to the rest of the body.</p><p>Red blood cells are usually shaped like a disk, with a depressed centre, like a donut without a hole. In HS, most red blood cells are circular and shaped like spheres. These are called spherocytes.</p><p>HS is the most common form of inherited hemolytic anemia. “Hemolytic” refers to hemolysis, which is the breakdown of the red blood cells. Anemia is a lack of either hemoglobin or red blood cells in the body.</p><h2>Key points</h2><ul><li>Hereditary spherocytosis (HS) is an inherited blood disorder of the red blood cells.</li><li>HS affects approximately 1 in 2000-3000 people. The number of cases may be higher as mild cases can go undiagnosed.</li><li>A person can inherit HS through an autosomal dominant inheritance, autosomal recessive inheritance, or a de novo mutation. A de novo mutation occurs by chance and is not inherited from either parent.</li></ul><h2>How is hereditary spherocytosis inherited?</h2><p>In most cases, HS is an inherited genetic condition, which means that the genes involved in HS are typically passed down from one or both parents to their children. </p><p>Although HS occurs in all racial groups, it is more common in people of Northern European descent. HS affects approximately 1 in 2000-3000 people. The number of cases of HS may be underestimated because mild cases can go undiagnosed. </p><p>A gene is a section of DNA that gives specific instructions to a cell. Most of the time, the instruction is a recipe for making a protein. A change (mutation) in a gene results in a protein that cannot function properly. </p><p>In general, each person has two copies of every gene. One copy is inherited from the mother and the other from the father. There are three possible ways a person can inherit HS. </p><h3>Autosomal dominant inheritance </h3><p>Autosomal dominant inheritance occurs when one parent is affected with HS and the other parent is unaffected. One normal gene from the unaffected parent, and one gene with a mutation from the affected parent, are passed down to the child. In autosomal dominant inheritance, only one abnormal copy of the gene is needed to cause disease. A parent affected with HS has a 50% chance of passing the condition on to the child.</p> <figure class="asset-c-80"> <span class="asset-image-title">Autosomal dominant inheritance</span> <img src="https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_dominant_EN.jpg" alt="" /> </figure> <p>Autosomal dominant inheritance occurs in approximately 70% to 80% of HS cases. </p><h3>Autosomal recessive inheritance</h3><p>In autosomal recessive inheritance both copies of the gene passed down to a child are abnormal and result in HS. In this scenario, both copies of the gene need to have a mutation to cause disease. Parents usually show no signs or symptoms of the disease as they typically have one normal copy of the gene and one abnormal copy of the gene (they are known as “carriers”). </p> <figure class="asset-c-80"> <span class="asset-image-title">Autosomal recessive inheritance</span> <img src="https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_recessive_EN.jpg" alt="" /> </figure> <p>Autosomal recessive inheritance occurs in approximately 10% of HS cases.</p><h3>De novo mutation</h3><p>HS can be caused by a new (de novo) mutation that occurred by chance when the baby was conceived. It was not passed down from either parent. </p> <figure class="asset-c-80"> <span class="asset-image-title">De novo mutation</span> <img src="https://assets.aboutkidshealth.ca/akhassets/de_novo_mutation_EN.jpg" alt="" /> </figure> <p>De novo mutations occur in approximately 20% of HS cases, however the exact number of de novo mutations in HS is not known.</p>https://assets.aboutkidshealth.ca/akhassets/IMD_autosomal_dominant_EN.jpgHereditary spherocytosis: GeneticsFalse