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Am J Hum Genet. Mar 1995; 56(3): 630–639.
PMCID: PMC1801164

Galactosemia: a strategy to identify new biochemical phenotypes and molecular genotypes.


We describe a stratagem for identifying new mutations in the galactose-1-phosphate uridyl transferase (GALT) gene. GALT enzyme activity and isoforms were defined in erythrocytes from probands and their first-degree relatives. If the biochemical phenotypes segregated in an autosomal recessive pattern, we screened for common mutations by using multiplex PCR and restriction endonuclease digestions. If common mutant alleles were not present, the 11 exons of the GALT gene were amplified by PCR, and variations from the normal nucleotide sequences were identified by SSCP. The suspected region(s) was then analyzed by direct DNA sequencing. We identified 86 mutant GALT alleles that reduced erythrocyte GALT activity. Seventy-five of these GALT genomes had abnormal SSCP patterns, of which 41 were sequenced, yielding 12 new and 21 previously reported, rare mutations. Among the novel group of 12 new mutations, an unusual biochemical phenotype was found in a family whose newborn proband has classical galactosemia. He had inherited two mutations in cis (N314D-E203K) from his father, whose GALT activity was near normal, and an additional GALT mutation in the splice-acceptor site of intron C (IVSC) from his mother. The substitution of a positively charged E203K mutation created a unique isoform-banding pattern. An asymptomatic sister's GALT genes carries three mutations (E203K-N314D/N314D) with eight distinct isoform bands. Surprisingly, her erythrocytes have normal GALT activity. We conclude that the synergism of pedigree, biochemical, SSCP, and direct GALT gene analyses is an efficient protocol for identifying new mutations and speculate that E203K and N314D codon changes produce intraallelic complementation when in cis.

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  • Andersen MW, Williams VP, Helmer GR, Jr, Fried C, Popják G. Transferase-deficiency galactosemia: evidence for the lack of a transferase protein in galactosemic red cells. Arch Biochem Biophys. 1983 Apr 1;222(1):326–331. [PubMed]
  • Andersen MW, Williams VP, Sparkes MC, Sparkes RS. Transferase-deficiency galactosemia: immunochemical studies of the Duarte and Los Angeles variants. Hum Genet. 1984;65(3):287–290. [PubMed]
  • Beutler E. Screening for galactosemia. Studies of the gene frequencies for galactosemia and the Duarte variant. Isr J Med Sci. 1973 Sep-Oct;9(9):1323–1329. [PubMed]
  • Beutler E, Baluda MC, Sturgeon P, Day RW. The genetics of galactose-1-phosphate uridyl transferase deficiency. J Lab Clin Med. 1966 Oct;68(4):646–658. [PubMed]
  • Elsas LJ, Dembure PP, Langley S, Paulk EM, Hjelm LN, Fridovich-Keil J. A common mutation associated with the Duarte galactosemia allele. Am J Hum Genet. 1994 Jun;54(6):1030–1036. [PMC free article] [PubMed]
  • Flach JE, Reichardt JK, Elsas LJ., 2nd Sequence of a cDNA encoding human galactose-1-phosphate uridyl transferase. Mol Biol Med. 1990 Aug;7(4):365–369. [PubMed]
  • Fox JG. Experience of the Manitoba Perinatal Screening Program, 1965-85. CMAJ. 1987 Nov 15;137(10):883–888. [PMC free article] [PubMed]
  • Frey PA, Wong LJ, Sheu KF, Yang SL. Galactose-1-phosphate uridylyltransferase: detection, isolation, and characterization of the uridylyl enzyme. Methods Enzymol. 1982;87:20–36. [PubMed]
  • Fridovich-Keil JL, Jinks-Robertson S. A yeast expression system for human galactose-1-phosphate uridylyltransferase. Proc Natl Acad Sci U S A. 1993 Jan 15;90(2):398–402. [PMC free article] [PubMed]
  • Kelley RI, Harris H, Mellman WJ. Characterization of normal and abnormal variants of galactose-1-phosphate uridylyltransferase (EC by isoelectric focusing. Hum Genet. 1983;63(3):274–279. [PubMed]
  • Kelley RI, Segal S. Evaluation of reduced activity galactose-1-phosphate uridyl transferase by combined radioisotopic assay and high-resolution isoelectric focusing. J Lab Clin Med. 1989 Aug;114(2):152–156. [PubMed]
  • Kühnl P, Nowicki L, Spielmann W. Untersuchungen zum Polymorphismus der Galaktose-1-Phosphat-Uridyltransferase (EC: mittels Agarosegelelektrophorese. Humangenetik. 1974;24(3):227–230. [PubMed]
  • Lee JE, Ng WG. Semi-micro techniques for the genotyping of galactokinase and galactose-1-phosphate uridyltransferase. Clin Chim Acta. 1982 Sep 30;124(3):351–356. [PubMed]
  • LELOIR LF. The enzymatic transformation of uridine diphosphate glucose into a galactose derivative. Arch Biochem Biophys. 1951 Sep;33(2):186–190. [PubMed]
  • Lemaire HG, 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. [PMC free article] [PubMed]
  • Leslie ND, Immerman EB, Flach JE, Florez M, Fridovich-Keil JL, Elsas LJ. The human galactose-1-phosphate uridyltransferase gene. Genomics. 1992 Oct;14(2):474–480. [PubMed]
  • Longo N, Langley SD, Griffin LD, Elsas LJ. Activation of glucose transport by a natural mutation in the human insulin receptor. Proc Natl Acad Sci U S A. 1993 Jan 1;90(1):60–64. [PMC free article] [PubMed]
  • Longo N, Shuster RC, Griffin LD, Langley SD, Elsas LJ. Activation of insulin receptor signaling by a single amino acid substitution in the transmembrane domain. J Biol Chem. 1992 Jun 25;267(18):12416–12419. [PubMed]
  • Mellman WJ, Tedesco TA. An improved assay of erythrocyte and leukocyte galactose-1-phosphate uridyl transferase: stabilization of the enzyme by a thiol protective reagent. J Lab Clin Med. 1965 Dec;66(6):980–986. [PubMed]
  • Reichardt JK, Belmont JW, Levy HL, Woo SL. Characterization of two missense mutations in human galactose-1-phosphate uridyltransferase: different molecular mechanisms for galactosemia. Genomics. 1992 Mar;12(3):596–600. [PubMed]
  • Reichardt JK, Berg P. Cloning and characterization of a cDNA encoding human galactose-1-phosphate uridyl transferase. Mol Biol Med. 1988 Apr;5(2):107–122. [PubMed]
  • Reichardt JK, Levy HL, Woo SL. Molecular characterization of two galactosemia mutations and one polymorphism: implications for structure-function analysis of human galactose-1-phosphate uridyltransferase. Biochemistry. 1992 Jun 23;31(24):5430–5433. [PubMed]
  • Reichardt JK, Novelli G, Dallapiccola B. Molecular characterization of the H319Q galactosemia mutation. Hum Mol Genet. 1993 Mar;2(3):325–326. [PubMed]
  • Reichardt JK, Packman S, Woo SL. Molecular characterization of two galactosemia mutations: correlation of mutations with highly conserved domains in galactose-1-phosphate uridyl transferase. Am J Hum Genet. 1991 Oct;49(4):860–867. [PMC free article] [PubMed]
  • Reichardt JK, Woo SL. 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. [PMC free article] [PubMed]
  • Shin YS, Niedermeier HP, Endres W, Schaub J, Weidinger S. Agarose gel isoelectrofocusing of UDP-galactose pyrophosphorylase and galactose-1-phosphate uridyltransferase. Developmental aspect of UDP-galactose pyrophosphorylase. Clin Chim Acta. 1987 Jun 30;166(1):27–35. [PubMed]
  • Sparkes MC, Crist M, Sparkes RS. Improved technique for electrophoresis of human galactose-1-p uridyl transferase (EC Hum Genet. 1977 Dec 29;40(1):93–97. [PubMed]
  • Tajima M, Nogi Y, Fukasawa T. Primary structure of the Saccharomyces cerevisiae GAL7 gene. Yeast. 1985 Sep;1(1):67–77. [PubMed]
  • Tedesco TA. Human galactose 1-phosphate uridyltransferase. Purification, antibody production, and comparison of the wild type, Duarte variant, and galactosemic gene products. J Biol Chem. 1972 Oct 25;247(20):6631–6636. [PubMed]

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