Severe erythrocyte adenylate kinase deficiency due to homozygous A → G substitution at codon 164 of human AK1 gene associated with chronic haemolytic anaemia

Abstract

Summary.A child of Italian origin with a congenital haemolytic anaemia had spectrophotometrically undetectable erythrocyte adenylate kinase (AK) activity. Her parents and brother had approximately 50% normal AK activity, and AK electrophoresis of red blood cell (RBC) crude extract on cellulose acetate strips showed the presence of the normal allele AK1-1. No AK band was detected in the AK electrophoresis of the proband, in whom the erythrocyte 2,3-diphosphoglycerate (2,3DPG) and glutathione (GSH) concentrations were normal whereas adenosine triphosphate (ATP) concentration, pyruvate kinase (PK) and glucose-6P-dehydrogenase (G6PD) activities were increased, reflecting the high reticulocyte count (6 . 9%). No other evident enzymatic defect was detected by standard procedures. Analysis of AK gene exons, based on polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP), clearly showed an abnormality in the fragment containing exon 6. The subsequent sequence analysis of this abnormal fragment revealed homozygous and heterozygous A → G substitutions in the proband and in the parents and brother respectively at codon 164, corresponding to a tyrosine → cysteine substitution in the AK protein.

Red cell adenylate kinase deficiency: molecular study of 3 new mutations (118G>A, 190G>A, and GAC deletion) associated with hereditary nonspherocytic hemolytic anemia

“…Conversely, patients with residual red cell AK activity that was only partially reduced (from 20% to 50% of normal) exhibit a mild to moderate hemolytic anemia but normal physical and mental development. 5,6,8 The finding by Beutler et al 4 of a child with total absence of RBC AK activity and no evidence of hemolysis or mental retardation raised a question regarding the cause-effect relationship between AK deficiency and hemolytic anemia. Some investigators suggested that the shortened survival of AK-deficient RBCs was caused, or at least enhanced, by the coexistence of defects of other enzymes such as phosphoribosyl pyrophosphate synthetase, pyruvate kinase, and AMP-guanosine triphosphate (GTP) phosphotransferase 6 ; glucose-6-phosphate dehydrogenase (G6PD) 1,7 ; or other unidentified factors.…”

“…Although in this case the neurologic impairment was attributed to the forceps delivery and resuscitation at birth, mental retardation from mild to severe has been later reported in other patients with severe red cell AK deficiency. [7][8][9] Since the AK1 isoenzyme is expressed in red cells and brain, it can be suggested that the mutation, especially in such cases of severe enzyme deficiency, may be accompanied by brain abnormalities. Conversely, patients with residual red cell AK activity that was only partially reduced (from 20% to 50% of normal) exhibit a mild to moderate hemolytic anemia but normal physical and mental development.…”

“…The first case, originally reported by Miwa et al 5 and Matsuura et al, 17 determined the nucleotide sequences of 2 alleles of the AK1 gene cloned from DNA, and a transition mutation (CGGϾTGG) was found in exon 6 on one allele, resulting in an Arg to tryptophan (Trp) substitution at the 128-amino acid residue of AK1. The second analysis of AK gene exons, 8 based on polymerase chain reaction-single-strand conformational polymorphism, showed an abnormality in the fragment containing exon 6. The subsequent sequence analysis of this abnormal fragment revealed homozygous and heterozygous AϾG substitutions at codon 164 in the proband and in the parents The N and C termini are labeled as N and C. The figure was produced using the program BOBSCRIPT.…”

Analysis of the genes expressed in Clonorchis sinensis adults using the expressed sequence tag approach

“…Under normal conditions, AK 1-knockout mice showed no phenotypic changes. However, under metabolic stress, compromised energetics were detected in the heart and skeletal muscle, suggesting the physiological significance of AK-catalysed phosphoryl transfer between the intracellular compartments in cellular energetic homoeostasis (Qualtieri et al 1997;Janssen et al 2001). The nucleoside analogues of AK have been used clinically for treating certain viral infections and malignant diseases (Pucar et al 2000;Bourdais et al 1996;Schneider et al 1998).…”

Physiological significance and molecular genetics of red cell enzymes involved in the ribonucleotide metabolism

“…Both 491G and 382T are located in the exon 6 of AK1 gene, suggesting that this region encodes crucial amino acid residues. 47) Recently, a nonsense mutation at colon 107, 319CGA -~ TGA, of the AK1 gene has been revealed in two siblings of Italian origin.48) The proband showed mild chronic hemolytic anemia as well as psychomotor impairment. The mutation causes truncation of the AK1 polypeptide, resulting in complete loss of AK1 activity in the affected RBC.…”