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A mutation common in non‐jewish Tay–Sachs disease: Frequency and RNA studies
Author(s) -
Akerman B. R.,
Zielenski J.,
TriggsRaine B. L.,
Prence E. M.,
Natowicz M. R.,
LimSteele J. S. T.,
Kaback M. M.,
Mules E. H.,
Thomas G. H.,
Clarke J. T. R.,
Gravel R. A.
Publication year - 1992
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.1380010407
Subject(s) - biology , allele , genetics , exon , tay sachs disease , mutation , allele frequency , population , splice site mutation , microbiology and biotechnology , gene , alternative splicing , disease , medicine , environmental health , pathology
Tay‐Sachs disease (TSD) is an autosomal recessive genetic disorder resulting from mutation of the HEXA gene encoding the α‐subunit of the lysosomal enzyme, β‐N‐acetylhexosaminidase A (Hex A). We have discovered that a Tay‐Sachs mutation, IVS‐9 + 1 G→A, first detected by Akli et al. (Genomics 11:124–134, 1991), is a common disease allele in non‐Jewish Caucasians (10/58 alleles examined). A PCR‐based diagnostic test, which detects an Nla III site generated by the mutation, revealed a frequency among enzyme‐defined carriers of 9/64 (14%). Most of those carrying the allele trace their origins to the United Kingdom, Ireland, or Western Europe. It was not identified among 12 Black American TSD alleles or in any of 18 Ashkenazi Jewish, enzyme‐defined carriers who did not carry any of the mutations common to this population. No normally spliced RNA was detected in PCR products generated from reverse transcription of RNA carrying the IVS‐9 mutation. Instead, the low levels of mRNA from this allele were comprised of aberrant species resulting from the use of either of two cryptic donor sites, one truncating exon 9 and the other within IVS‐9, spliced to exon 10. Numerous additional splice products were detected, most involving skipping of one or more surrounding exons. Together with a recently identified allele responsible for Hex A pseudodeficiency (Triggs‐Raine et al. Am J Hum Genet, 1992), these two alleles accounted for almost 50% (29/64) of TSD or carrier alleles ascertained by enzyme screening tests in non‐Jewish Caucasians. © 1992 Wiley‐Liss, Inc.