Abstract
Purpose: :
X–linked Ocular albinism type 1 (OA1) is characterized by a severe reduction in visual acuity, foveal hypoplasia, nystagmus, hypopigmented retina, the presence of macromelanosomes in the skin and eyes, and the misrouting of optic pathways. The goal of this study was to screen the OA1 gene for mutations in a large 4–generation Missouri family.
Methods: :
A large 45 member Missouri family affected with X–linked ocular albinism (XLOA) was identified. Eight affected males and thirteen heterozygous female family members were identified with typical signs of X–linked ocular albinism. Genomic DNA was extracted from the leukocytes from enrolled family members. For exon scanning of the OA1 gene primers were designed to anneal about 50 bp from the intron–exon junction. PCR and sequencing of each exon was done using standard methods.
Results: :
Mutation screening and sequence analysis of the OA1 gene revealed a novel 250delC mutation in exon 1. The mutation segregated with the ocular albinism phenotype. The affected male individuals were hemizygous for the mutation whereas female patients that were diagnosed as heterozygous based on the clinical exam were also heterozygous for the mutation. The deletion causes a frame shift following codon 83 ultimately resulting in a premature stop.
Conclusions: :
A novel mutation in the OA1 gene was identified in a family with X–linked ocular albinism confirming that the OA1 gene plays an essential role for normal ocular function.
Keywords: mutations • retinal degenerations: hereditary • retina