AN A-TO-G MUTATION AT THE -POSITION OF INTRON-8 OF THE HEXA GENE IS ASSOCIATED WITH EXON-8 SKIPPING AND TAY-SACHS-DISEASE(3)

Tay-Sachs disease (TSD) results from a deficiency of beta-hexosaminida se A (EC 3.2.1.52) activity. A child with late-infantile TSD was found to have two HEXA mutations, 986 + 3A --> G (A --> G at the +3 positio n of intron 8) and 5336 --> A, associated with the variant BI form of TSD. We were able to detect exon 8-deleted, but no correctly spliced H EXA mRNA, from the non-533G --> A allele in this patient. This suggest s that 986 + 3A --> G results in missplicing and, together with 533G - -> A, TSD. (C) 1995 Academic Press, Inc.