FURTHER INVESTIGATION OF THE HEXA GENE INTRON-9 DONOR SPLICE-SITE MUTATION FREQUENTLY FOUND IN NON-JEWISH TAY-SACHS-DISEASE PATIENTS FROM THE BRITISH-ISLES

In a previous study we found that a Tay-Sachs disease (TSD) causing mu tation in the intron 9 donor splice site of the HEXA gene occurs at hi gh frequency in non-Jewish patients and carriers from the British Isle s. It was found more frequently in subjects of Irish, Scottish, and We lsh origin compared with English origin (63% and 31% respectively). We have now tested, in a blind study, 26 American TSD carriers and 28 no n-carriers who have British ancestry for the intron 9 splice site muta tion. Six of the carriers and none of the controls were positive for t he mutation. All six had Irish ancestry, compared with nine of the 20 other (intron 9 mutation negative) TSD carriers (p < 0.05). These resu lts confirm the previously found high frequency of the intron 9 mutati on in non-jewish TSD families of British Isles, particularly Irish, or igin, and reinforce the need to screen such families for this mutation .