The Molecular Basis of a Case of γ-Glutamylcysteine Synthetase Deficiency

• Published in: Blood Vol. 94; no. 8; pp. 2890 - 2894
• Main Authors: Beutler, Ernest, Gelbart, Terri, Kondo, Takahito, Matsunaga, Alison T.
• Format: Journal Article
• Language: English
• Published: Washington, DC The Americain Society of Hematology 15.10.1999
• Subjects: Adolescent; Amino Acid Metabolism, Inborn Errors - blood; Amino Acid Metabolism, Inborn Errors - genetics; Amino Acid Sequence; Amino Acid Substitution; Anemia, Hemolytic - blood; Anemia, Hemolytic - enzymology; Anemia, Hemolytic - genetics; Anemias. Hemoglobinopathies; Animals; Base Sequence; Biological and medical sciences; Catalytic Domain - genetics; Codon - genetics; Consanguinity; Diseases of red blood cells; DNA Primers; DNA, Complementary - genetics; Erythrocytes - enzymology; Female; Genes; Glutamate-Cysteine Ligase - deficiency; Glutamate-Cysteine Ligase - genetics; Glutathione - deficiency; Hematologic and hematopoietic diseases; Homozygote; Humans; Learning Disabilities - blood; Learning Disabilities - enzymology; Learning Disabilities - genetics; Lymphocytes - chemistry; Medical sciences; Mice; Molecular Sequence Data; Point Mutation; Rats; Recombinant Fusion Proteins - metabolism; Species Specificity; Transfection; Human; Enzyme; Family study; Deficiency; Red blood cell; Metabolic diseases; Hemopathy; Enzymopathy; Genetic disease; Case study; Hemolytic anemia; Gene; Genetics; Mutation; Glutathione; Polymorphism
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V94.8.2890.420k16_2890_2894

γ-Glutamylcysteine synthetase catalyzes the first step in glutathione synthesis. The enzyme consists of 2 subunits, heavy and light, with the heavy subunit serving as the catalytic subunit. A patient with hemolytic anemia and low red blood cell glutathione levels was found to have a deficiency of γ-glutamylcysteine synthetase activity. Examination of cDNA from the patient and her mother showed that she was homozygous and that her mother was heterozygous for a A→T transversion at nt1109 producing a deduced amino acid change of His370Leu. The partial genomic structure of the catalytic subunit of γ-glutamylcysteine synthetase (GLCLC) was determined, providing some intron/exon boundaries to make it possible to sequence an affected part of the coding region from genomic DNA. The 1109A→T mutation was not present in the DNA of 38 normal subjects. In the course of these studies we found a diallelic polymorphism in nt +206 of an intron and another polymorphism that consisted of a duplication of a CAGC at cDNA nt1972-1975 in the 3′ untranslated region. The 2 polymorphisms were found to be only in partial linkage disequilibrium.