Abstract
Purpose: :
To identify TYR gene mutations in Israeli OCA patients, and correlate the mutations with ethnic origin.
Methods: :
Clinical evaluation included hair skin and eye examination, detailed pedigree analysis and ethnic origin of all 4 grandparents. Blood DNA was analyzed by PCR followed by restriction digest or by direct sequencing. Haplotype analysis was performed on families with more than one albino member and no identified mutation.
Results: :
349 Israeli OCA patients were screened for 13 TYR and 1 P gene mutations. Over 90% of the mutations were identified in Jewish and Christian Arab albinos with OCAI. No mutation was shared by Jews and Arabs. Sequencing analysis revealed an additional mutation in some albinos with one of the 8 "Jewish" and 5 "Christian Arab" common mutations, indicating the involvement of other gene(s). Arab families are highly consanguineous, however, 4 of the "Christian Arab" mutations were detected in various extended families, one of which was also found in homozygous state in Muslim Arab albino families, and another - as compound heterozygous in Druze albino families. Two mutations: IVS2-7T>A and R402Q were common in all Jewish populations, while E294K was identified only in Moroccan Jewish albinos, mainly from the city of Meknes. Six out of the eight "Jewish" TYR gene mutations were identified in Moroccan Jewish albinos, except for M1V, which was prevalent in all other North African albino subpopulations, and c.649delC which was identified in Sephardic Jews, mainly from Egypt. In Ashkenazi Jews only three mutations: IVS2-7T>A, R402Q and R217W, all causing the "milder" OCAI phenotype termed OCAIB, were identified.
Conclusions: :
Unlike all other publications on Caucasian OCAI patients, strong founder effect is suggested in Israeli subpopulations. Surprisingly, founder mutations were identified even in the highly consanguineous various Arab families, indicating possible family ties. Hence, an efficient and inexpensive screening program for OCA in Israeli populations can be developed.
Keywords: gene screening • mutations • genetics