The additional genetic diagnosis of homozygous sickle cell disease in a patient with Waardenburg-Shah syndrome: a case report.

Sickle cell disease can be diagnosed by newborn screening but, as in this case, may have a delayed presentation. The delay in diagnosis of homozygous sickle cell disease illustrates that other genetic disorders should be considered in patients who already have a diagnosis of one Mendelian disorder but show atypical features.