Disease severity in sibling pairs with type 1 Gaucher disease.

The only prognostic markers in Gaucher disease, the most common lysosomal storage disorder, are young age at first symptom/sign and the presence of null/severe mutations, both being predictive of more severe phenotypes. Therefore, it would be helpful to know whether siblings with the same genotype can be expected to experience comparable phenotypic expression. All non-neuronopathic sibling pairs in our referral clinic (1993-2008) with the same genotype were included.