A common mutation associated with the duarte galactosemia allele

• Published in: American journal of human genetics 1994-06, Vol.54 (6), p.1030-1036
• Main Authors: ELSAS, L. J, DEMBURE, P. P, LANGLEY, S, PAULK, E. M, HJELM, L. N, FRIDOVICH-KEIL, J
• Format: Article
• Language: English
• Subjects: 550900 > Pathology; ALDEHYDES; Alleles; Base Sequence; BASIC BIOLOGICAL SCIENCES; Biological and medical sciences; CARBOHYDRATES; Carbohydrates (enzymatic deficiencies). Glycogenosis; CLONING; DISEASES; DNA - blood; DNA HYBRIDIZATION; DNA Mutational Analysis; DNA SEQUENCING; DNA-CLONING; ENZYMES; Errors of metabolism; Erythrocytes - enzymology; Female; GALACTOSE; galactosemia; Galactosemias - enzymology; Galactosemias - epidemiology; Galactosemias - genetics; GENE MUTATIONS; genes; GLYCOSIDES; GLYCOSYL TRANSFERASES; HEXOSES; Humans; HYBRIDIZATION; Isoenzymes - blood; man; Medical sciences; METABOLIC DISEASES; Molecular Sequence Data; MONOSACCHARIDES; mutation; MUTATIONS; NUCLEOTIDES; ORGANIC COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; Phenotype; phenotypes; Point Mutation - genetics; Prevalence; PROTEINS; SACCHARIDES; STRUCTURAL CHEMICAL ANALYSIS; TRANSFERASES 550400 > Genetics; UDPG; UDPglucose-Hexose-1-Phosphate Uridylyltransferase - blood; UDPglucose-Hexose-1-Phosphate Uridylyltransferase - genetics; UTP-hexose-1-phosphate uridyltransferase
• ISSN: 0002-9297; 1537-6605

The human cDNA and gene for galactose-1-phosphate uridyl transferase (GALT) have been cloned and sequenced. A prevalent mutation (Q188R) is known to cause classic galactosemia (G/G). G/G galactosemia has an incidence of 1/38,886 in 1,396,766 Georgia live-born infants, but a more common variant of galactosemia, Duarte, has an unknown incidence. The proposed Duarte biochemical phenotypes of GALT are as follows: D/N, D/D, and D/G, which have approximately 75%, 50%, and 25% of normal GALT activity respectively. In addition, the D allele has isoforms of its enzyme that have more acidic pI than normal. Here we systematically determine (a) the prevalence of an A-to-G transition at base pair 2744 of exon 10 in the GALT gene, transition that produces a codon change converting asparagine to aspartic acid at position 314 (N314D), and (b) the association of this mutation with the Duarte biochemical phenotype. The 2744G nucleotide change adds an AvaII (SinI) cut site, which was identified in PCR-amplified DNA. In 111 biochemically unphenotyped controls with no history of galactosemia, 13 N314D alleles were identified (prevalence 5.9%). In a prospective study, 40 D alleles were biochemically phenotyped, and 40 N314D alleles were found. By contrast, in 36 individuals known not to have the Duarte biochemical phenotype, no N314D alleles were found. We conclude that the N314D mutation is a common allele that probably causes the Duarte GALT biochemical phenotype and occurs in a predominantly Caucasian, nongalactosemic population, with a prevalence of 5.9%.