PEX1 deficiency presenting as Leber congenital amaurosis

Peroxisome biogenesis disorders result from defects in peroxin proteins involved in peroxisomal matrix and membrane protein import. Peroxins are encoded in peroxin protein genes; to date, the PEX genes responsible for all 12 peroxisome biogenesis disorders complementation groups are known. Peroxin protein 1 deficiency associated with complementation group 1 is responsible for disease in approximately two thirds of all patients with a peroxisome biogenesis disorder. Their phenotypes range from severe to mild, and it appears to be a phenotype-genotype relationship. This case report describes a patient with peroxin protein 1 deficiency presenting as Leber congenital amaurosis, in whom the diagnosis was questioned at the age of 2 years when seizures first appeared and mild facial dysmorphia became evident.