Skip to main content
PMC home page
American Journal of Human Genetics logoLink to American Journal of Human Genetics
. 1991 Oct;49(4):860–867.

Molecular characterization of two galactosemia mutations: correlation of mutations with highly conserved domains in galactose-1-phosphate uridyl transferase.

J K Reichardt 1, S Packman 1, S L Woo 1
PMCID: PMC1683190  PMID: 1897530

Abstract

Galactosemia is an autosomal recessive disorder of human galactose metabolism caused by deficiency of the enzyme galactose-1-phosphate uridyl transferase (GALT). The molecular basis of this disorder is at present not well understood. We report here two missense mutations which result in low or undetectable enzymatic activity. First, we identified at nucleotide 591 a transition which substitutes glutamine 188 by arginine. The mutated glutamine is not only highly conserved in evolution (conserved also in Escherichia coli and Saccharomyces cerevisiae), but is also two amino acid residues downstream from the active site histidine-proline-histidine triad and results in about 10% of normal enzymatic activity. The arginine 188 mutation is the most common galactosemia mutation characterized to date. It accounts for one-fourth of the galactosemia alleles studied. Second, we report the substitution of arginine 333 by tryptophan, caused by a transition at nucleotide 1025. The area surrounding this missense mutation is the most highly conserved domain in the homologous enzymes from E. coli, yeast, and humans, and this mutation results in undetectable enzymatic activity, suggesting that this is a severe mutation. This second mutation appears to be rare, since it was found only in the patient we sequenced. Our data provide further evidence for the heterogeneity of galactosemia at the molecular level, heterogeneity which might be related to the variable clinical outcome observed in this disorder.

Full text

PDF
863

Images in this article

862Figure 1
on p.862
863Figure 2
on p.863

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Böhles H., Wenzel D., Shin Y. S. Progressive cerebellar and extrapyramidal motor disturbances in galactosaemic twins. Eur J Pediatr. 1986 Oct;145(5):413–417. doi: 10.1007/BF00439251. [DOI] [PubMed] [Google Scholar]
  2. Cooper D. N., Youssoufian H. The CpG dinucleotide and human genetic disease. Hum Genet. 1988 Feb;78(2):151–155. doi: 10.1007/BF00278187. [DOI] [PubMed] [Google Scholar]
  3. Dobbie J. A., Holton J. B., Clamp J. R. Defective galactosylation of proteins in cultured skin fibroblasts from galactosaemic patients. Ann Clin Biochem. 1990 May;27(Pt 3):274–275. doi: 10.1177/000456329002700317. [DOI] [PubMed] [Google Scholar]
  4. Field T. L., Reznikoff W. S., Frey P. A. Galactose-1-phosphate uridylyltransferase: identification of histidine-164 and histidine-166 as critical residues by site-directed mutagenesis. Biochemistry. 1989 Mar 7;28(5):2094–2099. doi: 10.1021/bi00431a019. [DOI] [PubMed] [Google Scholar]
  5. Flach J. E., Reichardt J. K., Elsas L. J., 2nd Sequence of a cDNA encoding human galactose-1-phosphate uridyl transferase. Mol Biol Med. 1990 Aug;7(4):365–369. [PubMed] [Google Scholar]
  6. Friedman J. H., Levy H. L., Boustany R. M. Late onset of distinct neurologic syndromes in galactosemic siblings. Neurology. 1989 May;39(5):741–742. doi: 10.1212/wnl.39.5.741. [DOI] [PubMed] [Google Scholar]
  7. Gitzelmann R., Steinmann B. Galactosemia: how does long-term treatment change the outcome? Enzyme. 1984;32(1):37–46. doi: 10.1159/000469448. [DOI] [PubMed] [Google Scholar]
  8. Kaufman F. R., Xu Y. K., Ng W. G., Donnell G. N. Correlation of ovarian function with galactose-1-phosphate uridyl transferase levels in galactosemia. J Pediatr. 1988 May;112(5):754–756. doi: 10.1016/s0022-3476(88)80697-8. [DOI] [PubMed] [Google Scholar]
  9. Kelley R. I., Feinberg D. M., Segal S. Galactose-1-phosphate uridyl transferase in density-fractionated erythrocytes. Studies of normal and mutant enzymes. Hum Genet. 1989 May;82(2):99–103. doi: 10.1007/BF00284037. [DOI] [PubMed] [Google Scholar]
  10. Lemaire H. G., Müller-Hill B. Nucleotide sequences of the gal E gene and the gal T gene of E. coli. Nucleic Acids Res. 1986 Oct 10;14(19):7705–7711. doi: 10.1093/nar/14.19.7705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Lo W., Packman S., Nash S., Schmidt K., Ireland S., Diamond I., Ng W., Donnell G. Curious neurologic sequelae in galactosemia. Pediatrics. 1984 Mar;73(3):309–312. [PubMed] [Google Scholar]
  12. Ng W. G., Xu Y. K., Kaufman F. R., Donnell G. N. Deficit of uridine diphosphate galactose in galactosaemia. J Inherit Metab Dis. 1989;12(3):257–266. doi: 10.1007/BF01799215. [DOI] [PubMed] [Google Scholar]
  13. Reichardt J. K., Berg P. Conservation of short patches of amino acid sequence amongst proteins with a common function but evolutionarily distinct origins: implications for cloning genes and for structure-function analysis. Nucleic Acids Res. 1988 Sep 26;16(18):9017–9026. doi: 10.1093/nar/16.18.9017. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Reichardt J. K., Woo S. L. Molecular basis of galactosemia: mutations and polymorphisms in the gene encoding human galactose-1-phosphate uridylyltransferase. Proc Natl Acad Sci U S A. 1991 Apr 1;88(7):2633–2637. doi: 10.1073/pnas.88.7.2633. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Rogers S., Holtzapple P. G., Mellman W. J., Segal S. Characteristics of galactose-1-phosphate uridyl transferase in intestinal mucosa of normal and galactosemic humans. Metabolism. 1970 Sep;19(9):701–708. doi: 10.1016/0026-0495(70)90067-3. [DOI] [PubMed] [Google Scholar]
  16. Russell J. D., DeMars R. UDP-glucose: alpha-D-galactose-1-phosphate uridylytransferase activity in cultured human fibroblasts. Biochem Genet. 1967 Jun;1(1):11–24. doi: 10.1007/BF00487732. [DOI] [PubMed] [Google Scholar]
  17. Segal S., Rogers S., Holtzapple P. G. Liver galactose-1-phosphate uridyl transferase: activity in normal and galactosemic subjects. J Clin Invest. 1971 Mar;50(3):500–506. doi: 10.1172/JCI106518. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Tajima M., Nogi Y., Fukasawa T. Primary structure of the Saccharomyces cerevisiae GAL7 gene. Yeast. 1985 Sep;1(1):67–77. doi: 10.1002/yea.320010108. [DOI] [PubMed] [Google Scholar]
  19. Waisbren S. E., Norman T. R., Schnell R. R., Levy H. L. Speech and language deficits in early-treated children with galactosemia. J Pediatr. 1983 Jan;102(1):75–77. doi: 10.1016/s0022-3476(83)80292-3. [DOI] [PubMed] [Google Scholar]

Articles from American Journal of Human Genetics are provided here courtesy of American Society of Human Genetics

RESOURCES