Comparison for functional aberration of G-6-PD deficiency variants with exon 10 mutations

Abstract

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is a common inherited enzyme deficiency in many parts of the world and there are many different variants described. Every G-6-PD deficiency variant has a unique underlying genetic defect, therefore it manifests specific properties. The single amino acid substitution in the globin chain is the commonest form of G-6-PD deficiency variant. Usually, the G-6-PD deficiency variant with the pathogenesis of a single amino acid substitution presents with only one aberration in secondary structure. Although many G-6-PD deficiency variants present similar structural abnormal points their functions sometimes are discordant. Here, the author performed a functional analysis on some alpha haemoglobinopathies using a novel bioinformatic tool, Polyphen. The mutations of five G-6-PD deficiency variants with exon 10 mutations, Guadalajara (386 Arg?Cys), Beverly Hills (387 Arg?His), Serres (361 Ala?Val), Iowa (385 Lys?Glu), and Clinic (405 Met?Ile) were selected for further study in this investigation. According to the in silico mutation study, the functional change in the G-6-PD deficiency variants with exon 10 mutations studied is variable. Here, it indicates that the functional aberration in the G-6-PD deficiency variant is based on complex pathogenesis. The identification of the structural aberration only in a G-6-PD deficiency variant is not sufficient and should be supplemented with a further functional analysis for a better insight in this topic.     

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.     

Mechanism of hemolysis of G-6-PD deficient red cells: changes in membrane lipids and polypeptides

Summary A study of red cell membrane polypeptide and lipid profiles in G-6-PD deficient subjects has been made. High membrane spectrin and lipid content was demonstrated in the red cells of drug sensitive G-6-PD deficient individuals, while it was normal in non-sensitive G-6-PD deficient subjects. An inverse relationship was observed between GSH level and spectrin content in the former group. Possible mechanism of increased spectrin content in relation to hemolysis is discussed.     

Glucose-6-Phosphate Dehydrogenase Deficiency in a Native Danish Family A New Variant

Deficiency of red cell glucose-6-phosphate dehydrogenase was found in a native Danish family, in which 2 boys suffered from severe haemolytic anaemia. The mother and 3 sisters of the boys were heterozygotes for G-6-PD deficiency. The biochemical investigations indicate that this deficient G-6-PD is very similar to the Mediterranean variant; however, this variant gene may represent another example of G-6-PD ‘Helsinki’ or an unique variant with properties similar to G-6-PD B(—).     

高胆红素血症新生儿血清miR-122水平与肝功能各项指标及葡萄糖-6-磷酸脱氢酶缺乏的相关性研究

目的:探讨高胆红素血症(NHB)新生儿血清miR-122表达与肝功能各项指标和葡萄糖-6-磷酸脱氢酶(G-6-PD)缺乏的相关性。方法:将2020年3月至5月于我院新生儿科足月分娩的新生儿217例,根据临床症状和血清总胆红素(TBil)检测结果分为NHB组(n=144)和非NHB组(n=73),比较两组新生儿肝功能各项指标[谷丙转氨酶(ALT)、谷草转氨酶(AST)、TBil、白蛋白(Alb)、碱性磷酸酶(ALP)、谷氨酰转肽酶(GGT)]以及红细胞G-6-PD酶活性。采用实时荧光定量PCR法检测患儿血清miR-122相对表达量,并分析其与各指标之间的关系。结果:与非NHB组相比,NHB组新生儿血清ALT、AST、GGT、Alb、TBil、CRP水平(Z=-11.858~-2.126,均P<0.05)以及血清miR-122相对表达量(t=4.721,P<0.05)显著升高。根据血清TBil水平,将NHB患儿分为轻度、中度、重度3个亚组;与轻度亚组和中度亚组相比,重度亚组NHB新生儿血清ALT、AST、GGT、TBil、CRP、PCT水平以及血清miR-122相对表达量均升高(H=6.045~63.896,均P<0.05)。NHB患儿血清miR-122相对表达量与ALT、AST、GGT、TBil、PCT水平呈正相关性(r=0.173~0.550,均P<0.05)。22例新生儿G-6-PD缺乏,其血清miR-122相对表达量显著高于G-6-PD正常新生儿(Z=36.831,P<0.05)。结论:在NHB新生儿中,血清miR-122相对表达量普遍升高,这与AST、ALT、AST、GGT、TBil、PCT水平升高、G-6-PD酶缺乏有关,因此加强血清miR-122水平检测有助于更准确地评估NHB患儿肝损伤情况。     

Red Cell Glucose-6-Phosphate Dehydrogenase Deficiency in Finland

Severe red cell glucose-6-phosphate dehydrogenase (G-6-PD) deficiency has been found in an ‘aboriginal’ Finnish family. 2 male and 9 female carriers of the variant G-6-PD were studied. The genetic pattern is consistent with x-linked recessive inheritance and the defect is associated with drug (primaquine) induced haemolysis. This was demonstrated by enzyme deficient red cell (⁵¹Cr-labelled) survival studies on a normal volunteer recipient. In addition, one of the hemizygotes studied had a slight chronic nonspherocytic haemolytic disorder. The partially purified enzyme had many of the characteristics of G-6-PD Mediterranean. The occurrence of this G-6-PD Mediterranean type variant in the Finnish population, which differs greatly from Mediterranean ethnic groups, as well as the association of slight chronic haemolysis with severe G-6-PD deficiency is discussed.     

Separate detection of glucose-6-phosphate dehydrogenase from 6-phosphogluconate dehydrogenase by DEAE-paper chromatography

Summary Red blood cell lysates were applied to DEAE cellulose paper for detection of glucose-6-phosphate dehydrogenase. Glucose-6-phosphate dehydrogenase (G-6-PD) was separated from 6-phosphogluconate dehydrogenase (6-PGD) by DEAE-cellulose paper-chromatography and their activities were detected on the chromatogram by applying the reaction mixture. The fluorescence of NADPH formed by G-6-PD was not interfered with by 6-PGD activity. This is a sensitive procedure which detects slight loss of G-6-PD in red blood cells and could be applied to the detection of G-6-PD deficiency.     

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.     

Clinical,genetic, and biochemical features of G-6PDWest Virginia

A new mutation of the G-6PD gene at position 910 is described. Biochemical analysis suggests that a conformational change results in the enzymatic deficiency associated with G-6PD^{West Virginia}. © 1996 Wiley-Liss, Inc.     

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.     

Effect of glucose-6-phosphate dehydrogenase deficiency on some biophysical properties of human erythrocytes

Abstract

The most widespread erythrocyte enzyme defect throughout the world is glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. The diagnosis of G-6-PD deficiency may be missed during an acute hemolytic episode due to increased young red blood cells which have good enzyme activity. However this might be detected at a later stage when the patient is asymptomatic. This calls for a detailed investigation of the patient with an acute attack of hemolysis at a later stage. Blood samples were obtained from 45 G-6-PD deficient male patients with previously diagnosed disease [25 subjects were during hemolytic attack (Gp1) while the rest was outside acute hemolytic crisis (Gp2)] and 20 healthy male subjects. The effect of G-6-PD deficiency on the erythrocytes of the above groups was investigated by scanning electron microscope (SEM) complemented with dielectric spectroscopy. The quantification of the morphological shape changes revealed that Gp1 had a significant increase in spheroechinocytes as well as in the morphological index in comparison with those of all other groups. The overall electrical and morphological properties of the red cell membrane of these subjects modified to a great extent during hemolytic attack. This may have important diagnostic and research implications. Thus the combined application of dielectric spectroscopy and SEM can be used as an efficient manner for monitoring abnormalities in blood and erythrocytes due to G-6-PD deficiency.     

Hematological parameters and red blood cell morphological abnormality of Glucose-6-Phosphate dehydrogenase deficiency co-inherited with thalassemia

Objective/Background

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and thalassemia are genetically independent hemolytic disorders. Co-inheritance of both disorders may affect red blood cell pathology to a greater extent than normally seen in either disorder alone. This study determines the prevalence and evaluates hematological changes of G-6-PD deficiency and thalassemia co-inheritance.

Anemia in Patients with Coinherited Thalassemia and Glucose-6-Phosphate Dehydrogenase Deficiency

Thalassemia and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency are genetic disorders that cause hemolytic anemia. In areas with high frequencies of both hematological disorders, coinheritance of G-6-PD deficiency with thalassemia can be found. Whether G-6-PD deficiency, coinherited with thalassemia, enhances severe anemia is still unclear. Hematological parameters between thalassemia carriers with G-6-PD deficiency and those without G-6-PD deficiency were compared. The G-6-PD deficiency was diagnosed in 410 blood samples from thalassemia patients using a fluorescent spot test. The levels of hemoglobin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV) and Hb A₂/Hb E [β26(B8)Glu→Lys; HBB: c.79G>A] were measured using an automated blood counter and high performance liquid chromatography (HPLC), respectively. The G-6-PD deficiency was found in 37 samples (9.02%). Mean levels of Hb, PCV, MCV and Hb A₂/E were similar between the two groups. Thus, G-6-PD deficiency did not enhance red blood cell pathology or induce more anemic severity in thalassemia patients.     

Erythrocyte Enzymes in Myelomatosis

The activity of the erythrocyte enzymes: glucose-6-phosphate dehydrogenase, pyruvate kinase, glutathion reductase and ATPase were measured in 8 patients with untreated myelomatosis. Glucose-6-phosphate dehydrogenase was significantly increased. Glucose-6-phosphate dehydrogenase values were negatively correlated with the glomerular filtration rate as measured by ⁵¹Cr-EDTA clearance. The results support the existence of a shortened red cell survival in peripheral blood related to the degree of renal insufficiency.     

Biochemical and molecular characterization of a new sporadic glucose-6-phosphate dehydrogenase variant described in Italy: G6PD Modena

Summary. A new glucose-6-phosphate dehydrogenase variant detected in an Italian man from the Po delata is described and designated as G6PD Modena. Biochemical characterization of the variant enzyme revealed an activity 21% of normal, a slow electrophoretic mobility, increased K_m value for NADP, decreased K_m value for G6P and a complete absence of NADPH inhibition, which could account for the apparently nonhaemolytic feature of this variant. The cloning and sequencing of the G6PD Modena allele showed a GC transition at nucleotide 844 in exon VIII causing a Asp His amino acid substitution. On the basis of biochemical characterization, G6PD Modena is classified as a genuine variant but it has the same mutation as G6PD Seattle-like.     

Profile of hepatocellular carcinoma in India: An insight into the possible etiologic associations

BACKGROUND: Several etiologic factors including hepatitis viruses, alcohol and aflatoxin have been implicated in the pathogenesis of hepatocellular carcinoma (HCC). There is, however, limited information from the Indian subcontinent. METHODS: Seventy-four consecutive cases of HCC were studied. A detailed history, tests for hepatitis B virus (HBV; HBsAg, HBeAg, anti-HBe, IgG anti-HBc, anti-HBs and HBV-DNA), hepatitis C virus (HCV; anti-HCV and HCV-RNA) infection, liver histopathology and HBV-DNA integration by using Southern blot hybridization were studied. A p53 gene mutation was also studied by using PCR and single-strand conformation polymorphism. RESULTS: Hepatocellular carcinoma patients were predominantly males (mean age 49.5 +/- 14.0 years). Portal hypertension and cirrhosis were seen in 56 (76%) patients, more often (P < 0.05) in viral marker positive cases. Forty-five percent of patients had features of hepatic decompensation at presentation. Evidence of HBV infection was present in 53 (71%) patients. Twenty-six (49%) of these patients had either HBeAg + ve, HBV-DNA + ve (n = 12), or HBsAg - ve, HBV-DNA + ve (n = 14) forms of HBV infection. Hepatitis B virus DNA integration in the liver tissue was seen in 10 of 17 (59%) patients. Infection with HCV alone was detected in three (4%) and dual HBV and HCV infection in six (8%) patients. A majority (78.5%) of the chronic alcoholics had associated viral infection. The etiology of HCC remained undetermined in 15 (20%) patients. The p53 gene mutations were detected only in three of 21 (14%) liver tissues. Aflatoxin toxicity, oral contraceptive use or metabolic disorder were not seen. CONCLUSIONS: In India: (i) HBV infection is the predominant factor for the development of HCC, often related to mutant forms of HBV; (ii) a majority of the HCC patients have overt cirrhosis of the liver; and (iii) HCV and alcohol per se are uncommonly associated.