A trinucleotide deletion together with a base duplication event at codon 439 in the human tyrosinase gene identifies a mutational hotspot.
Molecular analysis of the human tyrosinase gene in two patients suffering from a temperature-sensitive form of albinism has identified a thymine triplet deletion at codon 439 which is accompanied by a duplication of the immediately preceding cytosine residue. This results in a two base pair frame shift leading to premature termination at codon 448, giving a truncated protein. Its relationship to other mutations in tyrosinase and the possible cause are discussed. The temperature-sensitive phenotype is due to the guanine to adenine mutation at codon 422, known to generate a temperature-sensitive enzyme. The CTTT at F439 in tyrosinase is also present at F508 in CFTR, the main mutation causing cystic fibrosis.
Breimer
L H
LH
Department of Chemical Pathology and Human Metabolism, Royal Free Hospital School of Medicine, London, UK.
Winder
A F
AF
Panayiotidis
P
P
Jay
M
M
Moore
A
A
Jay
B
B
D000293:Adolescent; D016115:Albinism, Oculocutaneous / Q000235:genetics; D001345:Autoradiography; D001483:Base Sequence; D003062:Codon / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000235:genetics*; D005810:Multigene Family; D009154:Mutation; D009841:Oligonucleotides / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D017384:Sequence Deletion
D003062:Codon; D009841:Oligonucleotides; D014442:Monophenol Monooxygenase