| IDENTIFICATION OF SPECIES OF ORIGIN |
Species of Origin Confirmed by Nucleoside Phosphorylase,Glucose-6-Phosphate Dehydrogenase, and Lactate Dehydrogenase Isoenzyme Electrophoresis |
| |
| Gene |
GALT |
| Chromosomal Location |
9p13 |
| Allelic Variant 1 |
606999.0006; GALACTOSEMIA |
| Identified Mutation |
GLN188ARG; Reichardt et al. [Am J Hum Genet 49: 860 (1991)] demonstrated a transition at nucleotide 591 that substituted arginine for glutamine-188. The mutated glutamine is not only highly conserved in evolution, but is also 2 amino acid residues downstream from the active site histidine-proline-histidine triad. Lymphoblasts from subjects homozygous for the GLN188ARG mutation show essentially no detectable GALT activity [Fridovich-Keil and Jinks-Robertson. Proc Nat Acad Sci USA 90: 398 (1993)]. |
| |
| Gene |
GALT |
| Chromosomal Location |
9p13 |
| Allelic Variant 2 |
606999.0002; GALACTOSEMIA |
| Identified Mutation |
ARG333TRP; In a classic galactosemic patient, Reichardt and Woo [Am J Hum Genet 47: A164 (1990); Proc Natl Acad Sci U S A 88: 2633 (1991)] found a methionine-to-lysine change at a position that is conserved in all eukaryotes sequenced to date but in none of the prokaryotes. The mutation reduced the specific activity of the mutated protein to about 4% of normal. |