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I. H. Maumenee, V. M. Villegas, N. J. Izquierdo; Leber Congenital Amaurosis in Puerto Rico and the United States Virgin Islands: Ascertainment, Genotype-phenotype Correlation and GIS Technology. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5340.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study consists of complete ascertainment of patients with Leber Congenital Amaurosis (LCA) in Puerto Rico (PR) and the United States Virgin Islands (USVI), study of genotype-phenotype correlations, genotype-genotype interactions, and application of geographic information system (GIS) technology in a defined disease and population.
We ascertained nine pedigrees, carrying a clinical diagnosis of LCA. Patients underwent a comprehensive ophthalmologic evaluation by one of the authors (NJI). Probands and secondary family members had peripheral blood drawn for DNA analysis. Probands underwent mutation screening using the Leber congenital amaurosis genotyping Microarray (Asper Biotechnology) chip followed by confirmatory DNA sequencing to include secondary family members. GIS coordinates were used to indicate their places of birth.
Table 1 summarizes the birthplaces, mutations, and polymorphisms. The most frequent mutation leading to LCA was a homozygous CRB1 mutation (CRB1-/-611del AAATAG) observed in 50% of patients born within the San Juan metropolitan area and surrounding region. One branch of a pedigree showed consanguinity and homozygosity whereas in another branch a patient heterozygous for the above mutation carried a second CRB1 mutation, resulting in compound heterozygosity. A homozygous mutation in the AIPL1 gene was the most common mutation in patients from the USVI (100%).No mutation was identified in four ostensibly unrelated families; consanguinity and isonomy were observed in one family each respectively.
Gene mutations leading to LCA in the Caribbean islands differ by region reflecting backgrounds of colonizers. Knowledge and availability of screening for genetic heterozygosity would permit reduction of blindness in the population. Similarly, patients who are potential treatment candidates are readily identified when indicated on a GIS map. At least one additional gene or mutation remain to be identified in the Puerto Rican population.
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