title: A Pst+ polymorphism in the HEXA gene with an unusual geographic distribution.
abstract: A polymorphic variant in the human HEXA gene is described. This gene encodes the alpha-subunit of hexosaminidase A, the enzyme which is deficient in Tay-Sachs disease (TSD). In individuals carrying the polymorphism there is a T-->C transition at position -6 in intron 13. The substitution creates a site for the restriction endonuclease Pst1. This variant has an unusual ethnogeographic distribution. It occurs on 1.4% of non-TSD carrier chromosomes in Ashkenazi Jews. All individuals ascertained carrying the Pst+ allele have ancestry in Lithuania, Belarus and Ukraine. By contrast, no individuals carrying the Pst+ allele have been detected among non-Jewish Lithuanians, Jews of Sephardic origin or in several other ethnic groups. Two unrelated non-Jewish families have been identified in which the Pst+ variant occurs. In both cases the variant occurs on a chromosome carrying a novel TSD mutation (G772C) association with the B1 phenotype. The Pst+ G772C chromosomes are of Scots-Irish descent.
authors.affiliation: Department of Biochemical Genetics, McGill University, Montreal Children's Hospital Research Institute, Quebec, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Kaplan
authors.forename: S
authors.initials: S
authors.lastname: Kapoor
authors.forename: D
authors.initials: D
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Fernandes
authors.forename: M
authors.initials: M
authors.lastname: Vienozinskis
authors.forename: A
authors.initials: A
authors.lastname: Mascisch
authors.forename: C R
authors.initials: CR
authors.lastname: Scriver
authors.forename: J
authors.initials: J
authors.lastname: Lim-Steele
authors.forename: M
authors.initials: M
authors.lastname: Kaback
authors.forename: K
authors.initials: K
authors.lastname: Zeiger
authors.forename: A
authors.initials: A
authors.lastname: Zoossman-Diskin
authors.forename: B
authors.initials: B
authors.lastname: Bonne-Tamir
authors.forename: E
authors.initials: E
authors.lastname: Landels
authors.forename: M
authors.initials: M
authors.lastname: Bobrow
authors.forename: P
authors.initials: P
authors.lastname: Hechtman
mesh_terms: D000483:Alleles; D001483:Base Sequence; D015252:Deoxyribonucleases, Type II Site-Specific; D054818:Hexosaminidase A; D006801:Humans; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D013661:Tay-Sachs Disease / Q000235:genetics*; D001619:beta-N-Acetylhexosaminidases / Q000235:genetics*
chemical_list: C024388:CTGCAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; D054818:Hexosaminidase A; D001619:beta-N-Acetylhexosaminidases