Two new mutations in a late infantile Tay-Sachs patient are both in exon 1 of the beta-hexosaminidase alpha subunit gene.
We have identified two new point mutations in the beta-hexosaminidase alpha subunit (HEX A) gene in a non-Jewish Tay-Sachs disease patient with an unusual late infantile onset disease phenotype. The patient was a compound heterozygote with each allele of the HEX A gene containing a different mutation in exon 1. One of these is a T to C transition in the initiation codon, expected to produce no alpha subunit and therefore a classical infantile phenotype. The unusual clinical aspects and later onset in the patient must therefore be a result of residual hexosaminidase A activity associated with a mutant alpha subunit containing the second mutation, substitution of serine for proline at amino acid 25 owing to a C to T change at nucleotide 73. Western blotting and DE-52 ion exchange chromatography have been used to examine the behaviour of this mutant alpha subunit.
Harmon
D L
DL
Division of Biomolecular Sciences, King's College London.
Gardner-Medwin
D
D
Stirling
J L
JL
D000595:Amino Acid Sequence; D001483:Base Sequence; D002675:Child, Preschool; D004247:DNA / Q000235:genetics; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D006579:Heterozygote; D054818:Hexosaminidase A; D006801:Humans; D008969:Molecular Sequence Data; D010641:Phenotype; D017354:Point Mutation; D011487:Protein Conformation; D016415:Sequence Alignment; D013661:Tay-Sachs Disease / Q000201:enzymology / Q000235:genetics*; D001619:beta-N-Acetylhexosaminidases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification
D004247:DNA; D054818:Hexosaminidase A; D001619:beta-N-Acetylhexosaminidases