|
|
| Line 13: |
Line 13: |
|
| |
|
| ==Overview== | | ==Overview== |
| '''Hereditary spherocytosis''' is a genetically-transmitted form of [[spherocytosis]], an auto-[[hemolysis|hemolytic]] [[anemia]] characterized by the production of red blood cells that are sphere-shaped rather than donut-shaped, and therefore more prone to [[hemolysis]].
| |
|
| |
|
| ==Prevalence== | | ==Prevalence== |
| It is the most common (1 in 5,000 of Northern European ancestry) disorder of the red cell membrane.
| | |
|
| |
|
| ==Pathophysiology== | | ==Pathophysiology== |
| Hereditary spherocytosis is an [[autosomal dominant]] trait, most commonly (though not exclusively) found in Northern European and Japanese families, although an estimated 25% of cases are due to spontaneous [[mutation]]s. A patient has a 50% chance of passing the disorder onto his/her offspring, presuming that his/her partner does not also carry the mutation.
| |
|
| |
| Hereditary spherocytosis is caused by a variety of molecular defects in the genes that code for [[spectrin]], [[ankyrin]], [[protein 4.1]], and other erythrocyte membrane proteins. These proteins are necessary to maintain the normal shape of an erythrocyte, which is a biconcave disk. The protein that is most commonly defective is [[ankyrin]]. As the spleen normally targets abnormally shaped red cells (which are typically older), it also destroys spherocytes.
| |
|
| |
|
| ==[[Spherocytosis#Symptoms|Symptoms]]== | | ==[[Spherocytosis#Symptoms|Symptoms]]== |
|
| |
|
| As in [[spherocytosis|non-hereditary spherocytosis]], the [[spleen]]'s [[hemolysis]] results in observational symptoms of [[Fatigue (physical)|fatigue]], [[pallor]], and [[jaundice]].
| |
|
| |
|
| ==[[Spherocytosis#Diagnosis|Diagnosis]]== | | ==[[Spherocytosis#Diagnosis|Diagnosis]]== |
|
| |
|
| In a [[peripheral blood smear]], the abnormally small [[red blood cell]]s lacking the central pallor as seen in [[spherocytosis|non-hereditary spherocytosis]] is typically more marked in hereditary spherocytosis.
| |
|
| |
|
| Other protein deficiencies cause [[hereditary elliptocytosis]], [[pyropoikilocytosis]] or [[stomatocytosis]].
| |
|
| |
|
| In longstanding cases and in patients who have taken [[iron]] supplementation or received numerous [[blood transfusion]]s, [[iron overload]] may be a significant problem, being a potential cause of [[cardiomyopathy]] and [[liver disease]]. Measuring iron stores is therefore considered part of the diagnostic approach to hereditary spherocytosis.
| | |
| | |
|
| |
|
| ==[[Spherocytosis#Treatment|Treatment]]== | | ==[[Spherocytosis#Treatment|Treatment]]== |
| As in [[spherocytosis|non-hereditary spherocytosis]], acute symptoms of [[anemia]] and hyperbilirubinemia indicate treatment with [[blood transfusion]]s or exchanges and chronic symptoms of [[anemia]] and [[splenomegaly]] indicate dietary supplementation of [[iron]] and [[splenectomy]], the surgical removal of the [[spleen]].
| |
|
| |
|
| Experimental [[gene therapy]] exists to treat hereditary spherocytosis in lab mice; however, this treatment has not yet been tried on humans and because of the risks involved in human gene therapy, it may never be.
| |
|
| |
|
| ==See also== | | ==Related Chapters== |
| {{otheruses4|aspects of spherocytosis specific to the hereditary form of the disorder|details that apply generally to this variant as well as others|Spherocytosis}} | | {{otheruses4|aspects of spherocytosis specific to the hereditary form of the disorder|details that apply generally to this variant as well as others|Spherocytosis}} |
|
| |
|