Molecular characterization of galactosemia (Type 1)mutations in Japanese

✍ Scribed by Jiro Ashino; Yoshiyuki Okano; Itsuzin Suyama; Takeshi Yamazaki; Makoto Yoshino; Jun-Ichi Furuyama; Hsien-Chin Lin; Juergen K. V. Reichardt; Gen Isshiki

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 631 KB
• Volume: 6
• Category: Article
• ISSN: 1059-7794
• DOI: 10.1002/humu.1380060108

✦ Synopsis

Cummunicated by Sauio L. C. Woo

We characterized two novel mutations of the galactose-1-phosphate uridyltransferase (GALT) gene in two Japanese patients with GALT deficiency and identified N 3 14D and R333W mutations, previously found in Caucasians. One novel missense mutation was an G-to-A transition in exon 8, resulting in the substitution of arginine by histidine at the codon 23 1 (R23 1H). GALT activity of the R23 1H mutant construct was reduced to 15% of normal controls in a COS cell expression system. The other was a splicing mutation, an A-to-G transition at the 38th nucleotide in exon 3 (318A+G), resulting in a 38-bp deletion in the GALT cDNA by activating a cryptic splice acceptor site. In seven Japanese families (14 alleles for classic form and one allele for Duarte variant) with GALT deficiency, the R231H and 318A-G mutations were found only on both alleles of the proband. T h e N314D and R333W mutations were found on one allele each. The Q l 8 8 R was prevalent in the United States but not in Japanese patients. The N314D mutation was associated with the Duarte variant in Japanese persons, as well as in the United States. We speculate that classic galactosemia mutations appear to differ between Japanese and Caucasian patients. Our limited data set on galactosemia mutations in Japanese suggests that the N 3 14D GALT mutation encoding the Duarte variant arose before Asian and Caucasian people diverged and that classic galactosemia mutations arose and/or accumulated after the divergence of Asian and Caucasian populations.