Abstract
Purpose:
To investigate mutations of the GTPase regulator interacting protein 1 (RPGRIP1) gene in two affected male siblings of a Japanese family with Leber congenital amaurosis (LCA, MIM 204000), and to characterize the related clinical features.
Methods:
After obtaining informed consent, genomic DNA was extracted from the peripheral blood of the proband, his brother, and his unaffected parents mutation screening was initially performed with microarrays to detect known and novel mutations of 33 genes associated with recessive retinitis pigmentosa, LCA, and Stargardt disease. All exons of the genes were amplified by the polymerase chain reaction (PCR), followed by analysis with resequencing custom microarrays.
Results:
Only exon 17 of the RPGRIP1 gene was not detected by microarray analysis in the proband and his brother. For confirmation, PCR primers were designed to target sequences from exons 16 and 18 flanking exon 17. PCR showed deletion of exon 17 with a truncated PCR product in the proband and his brother, while both the truncated and normal- sized products were found in the parents. These results revealed that both siblings had homozygous deletion of exon 17 of the RPGRIP1 gene, while their unaffected parents were heterozygous carriers.
Conclusions:
LCA was diagnosed in two patients from one Japanese family based on the results of clinical examination and genetic analyses. Although direct sequencing is useful for genetic diagnosis, identification of mutations is sometimes difficult. Detection of the defective region of a gene by microarray analysis may be helpful in such cases.
Keywords: 539 genetics •
696 retinal degenerations: hereditary •
604 mutations