| #605432 | ||||||||||
| RADIOULNAR SYNOSTOSIS WITH AMEGAKARYOCYTIC THROMBOCYTOPENIA | ||||||||||
| Phenotype Gene Relationships | ||||||||||
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| Clinical Synopsis | ||||||||||
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| A number sign (#) is used with this entry because of evidence that radioulnar synostosis with amegakaryocytic thrombocytopenia is caused by mutation in the HOXA11 gene (142958), which maps to 7p15. Thompson and Nguyen (2000) observed 2 families with autosomal dominant inheritance of radioulnar synostosis (179300) in association with amegakaryocytic thrombocytopenia. The fathers and all affected children in both families (2 of 3 in 1 family and both children in the other) had the same skeletal defect, proximal fusion of the radius and ulna, resulting in extremely limited pronation and supination of the forearm. Three of the 4 children with radioulnar synostosis also had symptomatic thrombocytopenia, with bruising and bleeding problems since birth, necessitating correction by bone marrow or umbilical cord stem cell transplantation. The fathers had normal platelet counts and no history of bleeding or bruising. Thompson and Nguyen (2000) showed that a mutation in the HOXA11 gene (142958.0001) was responsible for the phenotype. Thompson et al. (2001) provided full clinical details on the 2 families with autosomal dominant radioulnar synostosis and amegakaryocytic thrombocytopenia. Their family 1 had 2 affected sisters in whom thrombocytopenia was treated successfully with bone marrow transplantation. The father had proximal radioulnar synostosis, bilateral clinodactyly of the fifth digits (present also on the right hand of the older sister), and webbed fingers, but no hematologic abnormality. Both sisters had hip dysplasia with dislocation. In their family 2, Thompson et al. (2001) observed an affected sister and brother. The father had radioulnar synostosis and bilateral fifth digit clinodactyly. | ||||||||||
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