A novel mutation in the HEXA gene specific to Tay-Sachs disease carriers of Jewish Iraqi origin.
An increased frequency of carriers of 1:140, as defined by reduced hexosaminidase A (HexA) activity, was observed among Iraqi Jews participating in the Tay-Sachs disease (TSD) carrier detection program. Prior to this finding, TSD among Jews had been restricted to those of Eastern European (Ashkenazi) and Moroccan descent with carrier frequencies of 1:29 and 1:110 for Jews of Ashkenazi and Moroccan extraction, respectively. A general, pan-ethnic frequency of approximately 1:280 has been observed among other Jewish Israeli populations. Analysis of 48 DNA samples from Iraqi Jews suspected, by enzymatic assay, to be carriers revealed a total of five mutations, one of which was novel. In nine carriers (19%), a known mutation typical to either Ashkenazi or Moroccan Jews was identified. DeltaF304/ 305 was detected in four individuals, and + 1278TATC in three. G269S and R170Q each appeared in a single person. The new mutation, G749T, resulting in a substitution of glycine to valine at position 250 has been found in 19 of the DNA samples (40%). This mutation was not detected among 100 non-carrier, Iraqi Jews and 65 Ashkenazi enzymatically determined carriers. Aside from Ashkenazi and Moroccan Jews, a specific mutation in the HEXA gene has now also been identified in Jews of Iraqi descent.
Karpati
M
M
Genetic Institute, Sheba Medical Center, Tel Hashomer, Israel.
Peleg
L
L
Gazit
E
E
Akstein
E
E
Goldman
B
B
D019943:Amino Acid Substitution; D004247:DNA / Q000032:analysis / Q000097:blood; D017931:DNA Primers; D006801:Humans; D007493:Iraq / Q000208:ethnology; D007585:Jews / Q000235:genetics*; D009154:Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D013661:Tay-Sachs Disease / Q000208:ethnology / Q000235:genetics*; D054820:beta-Hexosaminidase alpha Chain / Q000235:genetics*
D017931:DNA Primers; D004247:DNA; C518253:HEXA protein, human; D054820:beta-Hexosaminidase alpha Chain