Three new variants of glucose-6-phosphate dehydrogenase associated with chronic nonspherocytic hemolytic anemia: G-6-PD Lincoln Park, G-6-PD Arlington Heights, and G-6-PD West Town

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency was identified in three children who were evaluated because of chronic nonspherocytic hemolytic anemia. One child is of German extraction, another Puerto Rican, and the third Mexican. In each of the patients the hemolytic process was well compensated, but each had one or more episodes of anemia following exposure to an oxidant drug or with infections. The electrophoretic, functional, and kinetic properties of the mutant enzymes, derived both from the patients' erythrocytes and from cultured fibroblasts, allowed each to be distinguished from G-6-PD variants previously described.     

G6PD San Francisco: a new variant of glucose-6-phosphate dehydrogenase associated with congenital nonspherocytic hemolytic anemia

Congenital nonspherocytic hemolytic anemia in an adult male of Scandinavian ancestry was associated with virtual absence of G6PD activity in red cells. Characterization of G6PD purified from leukocytes using standard WHO techniques revealed diminished electrophoretic mobility, marked lability on heating at 46 degrees C, normal pH optimum and utilization of alternate substrates (2-deoxy G6P, D-amino NADP), elevated Km NADP, and striking susceptibility to NADPH inhibition. The variant G6PD, which appears to be unique, has been designated G6PD San Francisco. An unusual feature of the variant enzyme, susceptibility to inactivation by brief periods of dialysis, could be prevented by addition of 200 microM NADP to the dialysis solution. In red cells, where G6PD activity was essentially absent, regeneration of reduced glutathione was totally curtailed in vitro, while in leukocytes, where residual G6PD activity was approximately 60% of normal, hexose monophosphate shunt activity, oxygen consumption during phagocytosis, and bacterial killing were unimpaired. Thus, instability of the variant enzyme rather than its unfavorable kinetics appeared to be an important determinant of abnormal cell function.     

Glucose-6-phosphate dehydrogenase (G-6-PD) mutations in Mexico: four new G-6-PD variants

Screening for mutations at the G-6-PD gene by PCR-SSCP combined with restriction enzyme analysis and DNA sequencing was performed in nine G-6-PD deficient individuals with negative results for the presence of the most frequent G-6-PD mutations previously observed in Mexican population. The variants G-6-PD Valladolid(406T), G-6-PD Durham(713G), and G-6-PD Viangchan(871A) and four new G-6-PD mutant alleles were identified. The new mutations are located at cDNA nt 376 A --> T (126 Asn --> Tyr), nt 770 G --> T (257 Arg --> Leu), nt 1094 G --> A (365 Arg --> His), and nt 1285 A --> G (429 Lys --> Glu) and they were named G-6-PD San Luis Potosi, G-6-PD Zacatecas, G-6-PD Veracruz, and G-6-PD Yucatán, respectively. To date, a total of 18 different G-6-PD variants have been observed in Mexico and several of them are common in Africa, South Europe, and Southeast Asia.     

Glucose-6-phosphate dehydrogenase aveiro: a de novo mutation associated with chronic nonspherocytic hemolytic anemia

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked enzyme abnormality. The clinical phenotype is variable but often predictable from the molecular lesion. Class I variants (the most severe forms of the disease) cluster within exon 10, in a region that, at the protein level, is believed to be involved in dimerization. Here we describe a de novo mutation (C269Y) of a new class I variant (G6PD Aveiro) that maps to exon 8. Mutant and normal alleles were found in both hematopoietic and buccal cells, indicating the presence of mosaicism. The available model of the protein predicts that this lesion lies in proximity to the dimer interface of the molecule. A possible mechanism to explain the severity of the defect is proposed. (Blood. 2000;95:1499-1501)     

Erythrocytosis due to bisphosphoglycerate mutase deficiency with concurrent glucose-6-phosphate dehydrogenase (G-6-PD) deficiency

A 28-year-old asymptomatic male of Iranian Jewish (Meshadi) heritage was found on routine exam to have an erythrocytosis (RBC = 6.22 x 10(12)/l, Hgb = 19.2 g/dl, Hct = 58.9%). Splenomegaly was absent on physical exam. There was no family history of erythrocytosis. His oxygen dissociation curve was left-shifted with a p50 of 19 mmHg (normal = 25-32 mmHg). Hemoglobin electrophoresis showed no abnormalities. DNA sequencing of the hemoglobin beta globin gene and both alpha globin genes did not reveal a mutation. A 2,3-bisphosphoglycerate (BPG) level was markedly decreased at 0.3 micromol/g Hb (normal = 11.4-19.4 micromol/g Hb). The patient's bisphosphoglycerate mutase (BPGM) enzyme activity was also markedly decreased at 0.16 IU/g Hb (normal = 4.13-5.43 IU/g Hb). A red cell enzyme panel revealed a markedly decreased G-6-PD level (0.3 U/g Hb, normal = 8.6-18.6 U/g Hb). His parents and a brother were also available for evaluation. Both parents showed normal 2,3-BPG levels but BPGM activity approximately 50% of normal. Paradoxically, the brother showed normal BPGM activity but a slightly decreased 2,3-BPG level. All family members had markedly decreased G-6-PD activity. DNA sequencing of the BPGM gene showed the propositus to be homozygous for 185 G-->A, Arg 62 Gln in exon 2. Thus, the erythrocytosis in this patient is secondary to low 2,3-BPG levels, due to a deficiency in BPG mutase. This appears due to consanguinity within this family.     

Acute hemolytic anemia induced by a pyrazolonic drug in a child with glucose-6-phosphate dehydrogenase deficiency

In a 36-month-old child a severe hemolytic anemia occurred after the administration of a pyrazolonic drug. Erythrocyte glucose-6-phosphate dehydrogenase activity was absent in the patient. Intermediate enzymatic levels were demonstrated in the mother and in the maternal grand-mother with a corresponding erythrocyte mosaicism at the methemoglobin elution test. Some cells showed Heinz bodies and peculiar changes in the morphology in the initial phase of the crisis. There is no mention in the literature of a hemolytic action of this drug.     

Chronic hemolytic anemia is associated with a new glucose-6-phosphate dehydrogenase in-frame deletion in an older woman

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder, is usually observed in hemizygote males and very rarely in females. The G6PD class 1 variants, very uncommon, are associated with chronic hemolytic anemia. Here we report a Portuguese woman who suffered in her sixties from a chronic hemolytic anemia due to G6PD deficiency. Molecular studies revealed heterozygosity for an in-frame 18-bp deletion, mapping to exon 10 leading to a deletion of 6 residues, 362-367 (LNERKA), which is a novel G6PD class 1 variant, G6PD Tondela. Two of her three daughters, asymptomatic, with G6PD activity within the normal range, are heterozygous for the same deletion. The patient's leukocyte and reticulocyte mRNA studies revealed an almost exclusive expression of the mutant allele, explaining the chronic hemolytic anemia. Patient whole blood genomic DNA HUMARA assay showed a balanced pattern of X chromosome inactivation (XCI), but granulocyte DNA showed extensive skewing, harboring the mutated allele, implying that in whole blood, lymphocyte DNA, with a very long lifetime, may cover up the current high XCI skewing. This observation indicates that HUMARA assay in women should be assessed in granulocytes and not in total leukocytes.     

Chronic nonspherocytic hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency: report of two families with novel mutations causing G6PD Bangkok and G6PD Bangkok Noi

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common hereditary enzymopathies worldwide. Mostly G6PD deficient cases are asymptomatic though they may have the risk of neonatal jaundice (NNJ) and acute intravascular hemolysis during oxidative stress. Chronic nonspherocytic hemolytic anemia (CNSHA) due to G6PD deficiency is rare. In Thailand, one case was reported 40 years ago and by biochemical study this G6PD was reported to be a new variant G6PD Bangkok. We, herein, report two families with CNSHA due to G6PD deficiency. In the first family, we have been following up the clinical course of the patient with G6PD Bangkok. In addition to chronic hemolysis, he had three acute hemolytic episodes requiring blood transfusions during childhood period. Multiple gallstones were detected at the age of 27. His two daughters who inherited G6PD Bangkok from him and G6PD Vanua Lava from his wife are asymptomatic. Both of them had NNJ and persistent evidences of compensated hemolysis. Molecular analysis revealed a novel missense mutation 825 G→C predicting 275 Lys→Asn causing G6PD Bangkok. In the second family, two male siblings are affected. They had NNJ and several hemolytic episodes which required blood transfusions. On follow-up they have been diagnosed with chronic hemolysis as evidenced by reticulocytosis and indirect hyperbilirubinemia. Molecular analysis revealed combined missense mutations in exons 12 and 13. The first mutation was 1376 G→T predicting 459 Arg→Leu (known as G6PD Canton) and the second one was 1502 T→G predicting 501 Phe→Cys. We designated the resulting novel G6PD variant, G6PD Bangkok Noi.     

A new glucose-6-phosphate dehydrogenase variant G6PD Sugao (826C-->T) exhibiting chronic hemolytic anemia with episodes of hemolytic crisis immediately after birth

A case of glucose-6-phosphate dehydrogenase (G6PD) deficiency associated with chronic hemolysis with episodes of hemolytic crisis immediately after birth is reported. The propositus was a 1-month-old Japanese male infant. Molecular analysis of the G6PD gene revealed a novel missense mutation (826C-->4T) in exon 8 predicting a single amino acid substitution, Pro276Ser. The mother was confirmed to be heterozygous for this mutation. We designated this novel class 1 variant as G6PD Sugao. Pro276 is a phylogenetically conserved residue that may play a significant role in dimer formation.     

A new glucose 6-phosphate dehydrogenase variant (G-6-PD Verona) in a patient with myelodysplastic syndrome

A 67-year-old woman investigated because of 'myelodysplastic syndrome' was found to have a 4-fold increase in G-6-PD activity in her erythrocytes. The enzyme was partially purified and characterized. On grounds of: (a) reduced electrophoretic mobility, (b) abnormal cathodic band(s) in isoelectrofocusing, (c) increased Michaelis constant for glucose 6-phosphate, (d) abnormal thermostability, and (e) abnormal interaction with the ligand NADPH, we conclude that this is a new structural variant which we designate G-6-PD Verona. G-6-PD Verona was the sole apparent source of G-6-PD activity in the patient's erythrocytes; by contrast, the patient's fibroblasts had only normal G-6-PH (type B). The patient's haematological course terminated into acute myeloid leukaemia. We believe G-6-PD Verona was the result of a somatic mutation in an X-chromosome which took place in a haemopoietic cell clone which subsequently underwent neoplastic transformation.     

Two new variants of glucose-6-phosphate dehydrogenase associated with hereditary non-spherocytic hemolytic anemia: G6PD Wayne and G6PD Huron

Two new deficient variants of glucose-6-phosphate dehydrogenase (G6PD) causing hereditary nonspherocytic hemolytic anemia (HNSHA) are described. Both of these are unique and they have been named G6PD Wayne and G6PD Huron. Patients with G6PD Wayne underwent splenectomy and no objective improvement was noted. The patients with G6PD Huron were under medical observation for a considerable period of time without the diagnosis of G6PD deficiency being entertained because the family was of Northern European origin. Since sporadic variants of G6PD causing HNSHA show no special racial predilection, the diagnosis of G6PD deficiency should always be considered in patients with this syndrome.     

葡萄糖-6-磷酸脱氢酶缺乏致重度溶血性黄疸1例报告

1病例资料患者男性,65岁。因“皮肤巩膜黄染、尿黄2天”于2020年4月14日入本院。患者入院前2天不明原因出现全身皮肤及巩膜黄染,小便呈浓茶样改变,伴头晕、乏力、口干、食欲减退。院外查血常规:红细胞2.40×1012/L,血红蛋白浓度89 g/L,平均血红蛋含白含量37.2 pg,平均红细胞体积111.2 fl,红细胞比容26.7%;尿常规:深黄色,隐血(+++),蛋白质(+++),胆红素(+),尿胆原(+);肝功能:总胆红素522.4μmol/L,直接胆红素63.79 umol/L,间接胆红素458.61μmol/L;α-羟丁酸脱氢酶897 U/L,乳酸脱氢酶963 U/L;腹部彩超:肝胆胰脾肾未见明显异常。门诊以“溶血性贫血”收治入院。入院查体:生命体征平稳,全身皮肤、巩膜重度黄染,心肺查体未见异常,腹部平坦,无压痛、反跳痛、肌紧张,肝脾未触及,墨菲式征阴性,肾区无叩痛,移动性浊音阴性,肠鸣音约4次/min。     

Deletion of leucine 61 in glucose-6-phosphate dehydrogenase leads to chronic nonspherocytic anemia,granulocyte dysfunction,and increased susceptibility to infections

In this study the blood cells of 4 male patients from 2 unrelated families with chronic nonspherocytic anemia and recurrent bacterial infections were investigated. The activity of glucose-6- phosphate dehydrogenase (G6PD) in the red blood cells and in the granulocytes of these patients was below detection level. Moreover, their granulocytes displayed a decreased respiratory burst upon activation. Sequencing of genomic DNA revealed a novel 3-base pair (TCT) deletion in the G6PD gene, predicting the deletion of a leucine at position 61. The mutant G6PD protein was undetectable by Western blotting in the red blood cells and granulocytes of these patients. In phytohemagglutinin-stimulated lymphocytes the G6PD protein was present, but the amount of G6PD protein was strongly diminished in the patients' cells. Purified mutant protein from an Escherichia coli expression system showed decreased heat stability and decreased specific activity. Furthermore, we found that the messenger RNA of G6PD(180-182delTCT) is unstable, which may contribute to the severe G6PD deficiency observed in these patients. We propose the name "G6PD Amsterdam" for this new variant.     

Heterozygous pyruvate kinase deficiency and severe hemolytic anemia in a pregnant woman with concomitant,glucose-6-phosphate dehydrogenase deficiency

Summary The aim of this paper is to describe the clinical and hematological characteristics of a 32-year-old woman with concomitant heterozygous pyruvate kinase (PK) and glucose-6-phosphate dehydrogenase (G6PD) deficiencies and severe hemolytic anemia during pregnancy. In 1964, Oski et al. [16] described a family in which a clinically healthy woman was heterozygous for both PK and G6PD deficiencies. To our knowledge, the present case is the first described in which the same condition is associated with hemolysis. A heterozygous condition for both enzymopathies was clearly demonstrated by family study criteria, and all other causes of hemolytic anemia were eliminated. No evidence of genetic relationship between the two disorders was demonstrated. Since late onset of hemolysis in heterozygous PK-deficient women has been observed in association with pregnancy and the molecular characteristics of the concomitant deficient G6PD enzyme were kinetically favorable, partial PK deficiency is suggested as the major cause of hemolysis in this patient.