Neonatal jaundice and molecular mutations in glucose-6-phosphate dehydrogenase deficient newborn infants

Molecular mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene and clinical manifestations of neonatal jaundice in 112 male and 50 female Chinese neonates with G6PD deficiency were studied. In the 112 males, the nucleotide (nt) 1376 (G→T) mutation was the dominant type (50.0%), followed by nt 1388 (G→A) (16.1%), nt 493 (A→G) (8.0%), nt 1024 (C→T) (6.2%), nt 95 (A→G) (5.4%), nt 392 (G→T) (1.8%), nt 487 (G→A) (1.8%), nt 871 (G→A) (0.9%), and nt 1360 (C→T) (0.9%). The nt 871 variant has not been reported in Taiwan before. The occurrence rates for nt 1376, nt 1388, nt 493, nt 95, and nt 1024 mutations in the 50 females were 44.0%, 18.0%, 12.0%, 6.0%, and 6.0%, respectively. The type of G6PD mutation in 10 male and 7 female neonates has not been identified yet. Although G6PD deficient neonates had higher frequency of phototherapy than G6PD normal neonates in both sexes, a significant difference in the prevalence of hyperbilirubinemia (peak bilirubin ≥ 15.0 mg/dl) between G6PD deficient and normal neonates was found only in males. Further analysis showed that duration of phototherapy was longer in G6PD deficient male neonates than in the control group, while the outcome of phototherapy was better in subjects with non-nt 1376 mutations than subjects with the nt 1376 mutation. Most (78.3%) of the 23 G6PD deficient neonates who subsequently suffered from neonatal hyperbilirubinemia carried the nt 1376 mutation. The results of this study indicate that the nucleotide substitution at 1376 is the most common and important mutation for G6PD deficiency in Chinese neonates in Taiwan. © 1996 Wiley-Liss, Inc.     

Molecular Epidemiological Survey of Glucose-6-Phosphate Dehydrogenase Deficiency and Thalassemia in Uygur and Kazak Ethnic Groups in Xinjiang,Northwest China

Glucose-6-phosphate dehydrogenase (G6PD) deficiency and thalassemia occur frequently in tropical and subtropical regions, while the prevalence of relationship between the two diseases in Xinjiang has not been reported. We aimed to determine the prevalence of these diseases and clarify the relationship between genotypes and phenotypes of the two diseases in the Uygur and Kazak ethnic groups in Xinjiang. We measured G6PD activity by G6PD:6PGD (glucose acid-6-phosphate dehydrogenase) ratio, identified the gene variants of G6PD and α- and β-globin genes by polymerase chain reaction (PCR)-DNA sequencing and gap-PCR and compared these variants in different ethnic groups in Xinjiang with those adjacent to it. Of the 149 subjects with molecular analysis of G6PD deficiency conducted, a higher prevalence of the combined mutations c.1311C?>?T/IVSXI?+?93T?>?C and IVSXI?+?93T?>?C, both with normal enzymatic activities, were observed in the Uygur and Kazak subjects. A case of rare mutation HBB: c.135delC [codon 44 (?C) in the heterozygous state], a heterozygous case of HBB: c.68A?>?G [Hb G-Taipei or β22(B4)Glu→Gly] and several common single nucleotide polymorphisms (SNPs) were found on the β-globin gene. In conclusion, G6PD deficiency with pathogenic mutations and three common α-thalassemia (α-thal) [–?–^SEA, ?α^3.7 (rightward), ?α^4.2 (leftward)] deletions and point mutations of the α-globin gene were not detected in the present study. The average incidence of β-thalassemia (β-thal) in Uygurs was 1.45% (2/138) in Xinjiang. The polymorphisms of G6PD and β-globin genes might be useful genetic markers to trace the origin and migration of the Uygur and Kazak in Xinjiang.     

Prevalence and molecular study of G6PD deficiency in Malaysian Orang Asli

This study aims to define the prevalence and the molecular basis of G6PD deficiency in the Negrito tribe of the Malaysian Orang Asli. Four hundred and eighty seven consenting Negrito volunteers were screened for G6PD deficiency through the use of a fluorescent spot test. DNA from deficient individuals underwent PCR‐RFLP analysis using thirteen recognized G6PD mutations. In the instances when the mutation could not be identified by PCR‐RFLP, the entire coding region of the G6PD gene was subjected to DNA sequencing. In total, 9% (44/486) of the sample were found to be G6PD‐deficient. However, only 25 samples were subjected to PCR‐RFLP and DNA sequencing. Of these, three were found to carry Viangchan, one Coimbra and 16, a combination of C1311T in exon 11 and IVS11 T93C. Mutation(s) for the five remaining samples are unknown. The mean G6PD enzyme activity ranged 5.7 IU/gHb in deficient individuals. Our results demonstrate that the frequency of G6PD deficiency is higher among the Negrito Orang Asli than other Malaysian races. The dual presence of C1311T and IVS11 T93C in 64% of the deficient individuals (16/44) could well be a result of genetic drift within this isolated group.     

贵州省从江县侗族人群葡萄糖-6-磷酸脱氢酶基因突变型的检测

目的了解贵州省从江县侗族葡萄糖-6-磷酸脱氢酶(Glucose-6-phosphate dehydrogenase,G6PD) 缺乏症的发生率、基因突变类型及特点。方法对贵州省从江县侗族524人采用四氮唑蓝定性法进行G6PD缺乏症初筛、G6PD／6PGD比值法验证．再经自然引物及错配引物介导的聚合酶链反应／限制性酶切分析法检测中国人常见的9种基因突变型,对于未定型采用变性梯度凝胶电泳法(DGGE)检查外显子2、8、9、12基因突变情况。结果 G6PD缺乏症34例,检出率为6．49％,其中检出G1388A突变4例、C592T突变18例。未定型12例经DGGE检测外显子突变情况,未发现突变,有待于进一步对其余外显子进行研究。结论贵州省从江侗族是G6PD缺乏症的高发区。592 C→T突变型为该地该民族常见突变型,而不是中国人常见的G1376T、G1388A或A95G突变型。此次基因突变型调查为了解贵州省少数民族G6PD缺乏症的分布特征提供了原始数据。     

Molecular heterogeneity of G6PD deficiency in an Amazonian population and description of four new variants

To characterize the molecular variation in the glucose-6-phosphate dehydrogenase gene (G6PD), 196 asymptomatic and unrelated male G6PD-deficient blood donors from Belém, an Amazonian metropolis (Brazil), were analyzed. This deficiency was detected by horizontal agarose gel electrophoresis and quantitative spectrophotometric assay for enzyme activity. The mutations were searched by PCR/RFLP, SSCP, and direct DNA sequencing. The most frequent G6PD variant was the widespread and common G6PD A- (202G --> A, 376A --> G) observed in 161 subjects (82.1%). Besides this, we found another form of G6PD A- (968T --> C, 376A --> G) in 14 (7.1%) individuals, G6PD Seattle (844G --> C) in 4.6%, G6PD Santamaria (542A --> T, 376A --> G) in 2.5%, and G6PD Tokyo (1246G --> A) in one blood donor. Four novel variants were also identified: G6PD Belém (409C --> T; Pro137His), G6PD Ananindeua (376A --> G, 871G --> A; Asn126Asp, Val291Met), G6PD Crispim with four point mutations (375G --> T, 379G --> T, 383T --> C, and 384C --> T) leading to three amino acid substitutions (Met125Ile, Ala127Ser, and Leu128Pro), and G6PD Amazonia (185C --> A; Pro62His). The reported frequencies do not reflect the real values for blood donors from Belém, since an excess of individuals with "non A-" phenotype was included in this study to enhance the probability to find rare variants. Haplotype analyses were carried out for the less common G6PD variants identified in our study using PCR/RFLP for five polymorphic sites (FokI, PvuII, PstI, BclI, NlaIII). G6PD Crispim and G6PD Amazonia variants presented the most common haplotype found in G6PD B (- - + - -). G6PD Belém presented two haplotypes (- - + + +, - + + + +) and G6PD Ananindeua was found with the + - + - + haplotype. The reported heterogeneity probably is due to the great miscegenation, characteristic of the population of the Amazonian region, besides the apparently common occurrence of recurrent mutations in the G6PD gene.     

Molecular heterogeneity of glucose-6-phosphate dehydrogenase (G6PD) variants in the south of Thailand and identification of a novel variant (G6PD Songklanagarind)

Two hundred and twenty-five G6PD-deficient subjects in Songklanagarind Hospital in the south of Thailand comprising 210 males and 15 females were studied. Neonatal jaundice was detected in 85% of these patients. Acute hemolysis related to infection was detected in 17.3% of the G6PD-deficient subjects. Drug-induced acute hemolysis was detected in 1.8% and favism was observed in 3.6% of G6PD-deficient patients. The molecular analysis was performed on 134 G6PD-deficient individuals by a combination of PCR-RFLP, multiplex polymerase chain reaction by multiple tandem forward primers and a common reverse primer assay (MPTP) and DNA sequencing to characterize the mutations of the samples with abnormal MPTP bands. We found 10 different missense G6PD mutations and the three most common variants were G6PD Viangchan 871,G-->A (31.3%), G6PD Kaiping 1388,G-->A (20.1%) and G6PD Mahidol 487,G-->A (17.2%) followed by G6PD Canton 1376,G-->T (9.7%), G6PD Union 1360,C-->T (2.2%), G6PD Gaohe 95,A-->G (1.5%), G6PD Quing Yuan 392,G-->T (0.7%), G6PD Mediterranean 563,C-->T (0.7%), G6PD Songklanagarind 196,T-->A (0.7%), silent mutation 1311,C-->T (6.7%), and uncharacterized variant (9%). A novel missense mutation at codon 196, TTC-->ATC in exon 4 of the G6PD gene predicting a single amino acid substitution, Phe66Ile was identified and we designated this novel class II variant as G6PD Songklanagarind. The G6PD variants among the Thais in the southern part are heterogeneous and G6PD Viangchan, Kaiping, Mahidol, and Canton variants account for about 78% of the cases. Our findings provide some evidence that G6PD Viangchan and Mahidol are common Southeast Asian variants and support the theory of genetic drifts throughout Southeast Asia.     

Molecular characterisation of red cell glucose-6-phosphate dehydrogenase deficiency in Singapore Chinese

Sixty-two G6PD deficient Chinese males have been investigated for the presence of seven mutations of the coding region of the G6PD gene by natural and artifically created amplified restriction sites. The results show that the G to T substitution at nucleotide (nt) 1376 and G to A substitution at nt 1388 represent 24% and 21% of G6PD deficiency, respectively, in the Singapore Chinese; 37% of the sample could not be characterised. The remaining samples were identified as follows: 10% C→T at nt 563, 5% A→G at nt 95, and 3% C→T at nt 1024. The G to A substitution (nt 487) and the substitution A→G (nt 493) were not present in this sample. None of the subjects with the Mediterranean mutation (563 C→T) had the silent mutation at 1311 (C→T). This study confirms the extreme molecular heterogeneity of the G6PD gene in the Chinese. © 1994 Wiley-Liss, Inc.     

G6PD Viangchan and G6PD Mediterranean are the main variants in G6PD deficiency in the Malay population of Malaysia

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked red blood cell enzymopathy common in malaria endemic areas. Individuals affected by this disease show a wide variety of clinical signs of acute hemolytic anemia. Mutations of the G6PD gene in the Malay population with G6PD deficiency in Kelantan, a state in North East Malaysia were studied. Ninety-three individuals with G6PD deficiency were subjected to mutation analysis of the G6PD gene using polymerase chain reaction based techniques of multiplex PCR. Of the ninety-three DNA samples studied, molecular defects were identified in 80 cases (86%). Variants were heterogeneous - 28.7% were found to have a G to A nucleotide change at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan. The other major mutations were G6PD Mediterranean, G6PD Vanua Lava, G6PD Coimbra, G6PD Kaiping, G6PD Orissa, G6PD Mahidol, G6PD Canton and G6PD Chatham. These results showed that there are heterogeneous mutations of the G6PD gene associated with G6PD deficiency and that G6PD Viangchan and G6PD Mediterranean account for the main variants in G6PD deficiency among the Malay population in Malaysia.     

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in Pakistani population

Introduction: Glucose‐6‐phosphate dehydrogenase (G6PD; E.C. 1.1.1.49) deficiency is the commonest inborn error of metabolism with more than 140 genetic variants. The incidence of G6PD deficiency is 2–9% in Pakistan, but G6PD variants were never studied comprehensively. We therefore designed this study to describe the frequency of G6PD variants and their associated enzyme activities in Pakistan. Methods: Patients diagnosed with G6PD deficiency were enrolled. RFLP‐PCR was utilized to identify common mutations previously reported from Asian countries. Where mutational analysis failed, amplification of 9–12 exons with subsequent gene sequencing was performed. G6PD enzyme activity was assessed through the quantitative enzyme assay. Results: Two hundred and seventy‐six G6PD‐deficient subjects (237 male and 39 women) were investigated. G6PD Mediterranean (563C‐T) was the most common genetic variant (n = 216 or 78%). G6PD Chatham (1003A‐G) and G6PD Orissa (131C‐G) were observed in 14 (5%) and two (0.7%) subjects respectively. A novel mutation 973 G‐A with a predicated amino acid change of asp325asn was identified in exon 9. This was named G6PD Karachi after the place of origin of proband. Polymorphism in position 1311C/T was uniformly observed with all variants. Forty‐three or 17% of DNA samples remained uncharacterized. Very low levels of G6PD enzyme activity was observed with 563C‐T mutation. Conclusion: We concluded that 563C‐T was the commonest G6PD variant, while 1003A‐G and 131C‐G were less‐frequent genetic variants of G6PD in Pakistani population. A novel genetic variant 973G‐A was also identified. Very low levels of G6PD enzyme activity was seen with G6PD 563C‐T. Mutational analysis failed in a significant proportion of samples warranting further work.     

Prevalence of Thalassemia and Glucose-6-Phosphate Dehydrogenase Deficiency in Newborns and Adults at the Ramathibodi Hospital,Bangkok, Thailand

Thalassemias and glucose-6-phosphate dehydrogenase (G6PD) deficiency are the most common inherited blood disorders. They are distributed among populations living in malaria endemic regions resulting in survival advantage from severe malaria disease. The aims of this study were to analyze the prevalence of thalassemias and G6PD deficiency at the Ramathibodi Hospital, Bangkok, Thailand. A total of 616 adult and 174?cord blood samples were collected and analyzed for red blood cell (RBC) parameters, hemoglobin (Hb) typing and DNA analysis for G6PD mutations and α-thalassemia (α-thal). The two most prominent types of thalassemia were heterozygous Hb E (HBB: c.79G>A), (19.5% in newborns and 35.6% in adults) followed by heterozygous α-thal-2 [–α^3.7 (rightward) deletion] at 18.7% in newborns and 19.5% in adults. After performing G6PD genotyping using multiplex amplification refractory mutation system-polymerase chain reaction (multiplex ARMS-PCR) for 10 G6PD mutations, the prevalence of G6PD mutation was found in 12.0% of newborns and 11.7% of adults. The G6PD Viangchan [871 (G>A)] is the most common G6PD mutation in newborns (42.9%) and adults (52.8%). In addition, coinheritance of various types of thalassemia with G6PD deficiency were found. The results indicated that heterozygous Hb E and G6PD Viangchan are predominant both in newborns and adults in this study.     

Two new mutations of the glucose-6-phospate dehydrogenase (G6PD) gene associated with haemolytic anaemia: clinical, biochemical and molecular relationships

In two unrelated Spanish males with glucose-6-phosphate dehydrogenase (G6PD) deficiency and haemolytic anaemia, and two different novel point mutations in the G6PD gene, have been identified. A C to T transition at nucleotide 406 resulting in a (136) Arg to Cys substitution and a C to G transition at nucleotide 1155 resulting in a (385) Cys to Trp substitution. These two molecular defects have not been described before and are designated G6PD Valladolid^{406 C→T} and G6PD Madrid^{1155 C→G} .
In vitro biochemical characterization of both mutant enzymes showed important differences in their molecular properties according to their different clinical behaviour. In G6PD Valladolid, the mutation of which is located in exon 5, the normal in vitro heat stability may explain its mild clinical expression (low-grade haemolysis interrupted by an acute haemolytic crisis at age 70). In G6PD Madrid, the mutation, located in exon 10, results in a deficient variant associated with neonatal jaundice and life-long chronic nonspherocytic haemolytic anaemia (CNSHA). This finding further emphasizes the importance of this specific region of the G6PD gene in the stabilization of the G6PD molecule. Putative relationships between these single point mutations and the molecular properties of the mutant enzymes are also discussed.     

Development and evaluation of a reverse dot blot assay for the simultaneous detection of six common Chinese G6PD mutations and one polymorphism

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited disorder worldwide including southern China. We developed and validated a reverse dot blot (RDB) assay for the rapid and simultaneous genotyping of six mutations (c.95A>G, c.871G>A, c.1004C>T, c.1024C>T, c.1376G>T and c.1388G>A), that were common mutations in the Chinese G6PD deficiency population, and one polymorphism (c.1311C>T). Reliable genotyping of wild-type and mutant genomic DNA samples was achieved by means of a test strip onto which allele-specific oligonucleotide probe lines are fixed in parallel. This method involves a multiplex PCR amplification of three fragments in the G6PD target sequence and a manual hybridization/detection protocol. The entire procedure starting from blood sampling to the identification of mutations requires less than 6 h. The diagnostic reliability of this reverse dot blot assay was evaluated on 207 pre-typed samples by using direct DNA sequence analysis in a blind study. The reverse dot blot typing was in complete concordance with the reference method. The reverse dot blot assay was proved to be a simple, rapid, highly accurate, and cost-effective method to identify common G6PD mutations in Chinese population.     

Molecular genetics of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Spain: identification of two new point mutations in the G6PD gene

Summary .In order to explore the nature of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Spain, we have analysed the G6PD gene in 11 unrelated Spanish G6PD-deficient males and their relatives by using the polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis combined with a direct PCR-sequencing procedure and PCR-restriction enzyme (RE) analysis. We have identified eight different missense mutations, six of which have been reported in previously described G6PD variants. In nine patients who had presented with acute favism we found the following mutations: G6PD A_^376G–202A (four cases)| G6PD Union^1360T (two cases), G6PD Mediterranean^563T, (one case) and G6PD Aures^143c (one case). In the remaining patient a novel A to G transition was found at nucleotide position 209 which has not been reported in any other ethnic group. This mutation results in a (70) Tyr to Cys substitution and the resulting G6PD variant was biochemically characterized and designated as G6PD Murcia. This new mutation creates a Bsp 12861 recognition site which enabled us to rapidly detect it by PCRRE analysis. In two patients with chronic non-spherocytic haemolytic anaemia (CNSHA) we found the underlying genetic defects, as had been noted previously, to be located within a cluster of mutations in exon 10. One of them had the T to C transition at nucleotide 1153, causing a (3 8 5) Cys to Arg substitution, previously described in G6PD Tomah. The other, previously reported as having a variant called G6PD Clinic, has a G to A transition at nucleotide 1215 that produces a (405) Met to He substitution, thus confirming that G6PD Clinic is a new class I variant.     

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in Chinese infants with or without severe neonatal hyperbilirubinaemia

Summary. To characterize mutations in the glucose-6-phosphate dehydrogenase (G6PD) gene in Chinese infants, we studied 213 G6PD-deficient infants without blood exchange transfusion (BET) therapy, and 34 patients who required BET therapy for their severe hyperbilirubinaemia after birth. Nine different point mutations were characterized in all infants. Of these mutations, the G to T substitution at cDNA nucleotide (nt) 1376, which accounts for the mutations in 131 (53.0%) neonates, followed by G to A substitution at nt 1388 in 18 (10.5%) infants, A to G substitution at nt 493 in 17 (6.9%) infants, A to G substitution at nt 95 in 10 (4.1%) infants, C to T substitution at nt 1024 in six (2.4%) infants, and G to T substitution at nt 392 in three (1.2%) infants, G to A substitution at nt 487 in two (0.8%) infants, C to T substitution at nt 1360 in two (0.8%) infants and C to T substitution at nt 592 in two (0.8%) infants. Mutations in 48 (19.5%) G6PD-deficient infants were not characterized. Most (64.7%) mutations in the G6PD-deficient infants who required BET therapy after birth result from a G to T substitution at nt 1376. The enzyme activity of G6PD deficient infants who required BET therapy is significantly lower than for those who did not, even in a group with the same variant (as in 1376 mutation). Severe neonatal jaundice requiring BET therapy can take place with the majority of variants encountered in this area.     

Glucose-6-Phosphate Dehydrogenase Variants Associated with Favism in Thai Children

In a study conducted at Songklanagarind Hospital in the south of Thailand, the subjects were 225 patients (210 boys and 15 girls) with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Favism was found in 3.6% of the G6PD-deficient children. Approximately one half of the G6PD-deficient patients with favism were younger than 2 years. Sudden onset of anemia was found within 1 to 3 days after ingestion of dried fava beans. The classic features of favism, which are pallor, hemoglobinuria, and jaundice, were detected in all cases. To characterize the known G6PD mutations in Thai children, molecular analysis was performed for 8 G6PD-deficient children with favism by a combination of polymerase chain reaction-restriction fragment length polymorphism analysis and amplification refractory mutation system analysis. The G6PD variants in these children were G6PD Kaiping 1388,G-->A; G6PD Mahidol 487,G-->A; G6PD Viangchan 871,G-->A; and uncharacterized mutation with silent mutation 1311,C-->T.     

A new exon 9 glucose-6-phosphate dehydrogenase mutation (G6PD "Rehovot") in a Jewish Ethiopian family with variable phenotypes

Hereditary nonspherocytic hemolytic anemia (HNSHA) is a rare manifestation of glucose-6-phosphate dehydrogenase (G6PD) gene mutations, caused mainly by mutations located in exon 10 of the G6PD gene and less commonly by mutations in other parts of the gene. A new, exon 9, single-base mutation representing a T --> C transition at cDNA nucleotide 964 was found in three brothers and their carrier mother of Jewish Ethiopian descent. Biochemical characterization of the resultant protein was not performed. Though clinical manifestations included HNSHA in all cases, the severity of hemolysis and the transfusion requirement differed markedly. Severe congenital neutropenia (Kostmann's syndrome)--a disorder never reported before in conjunction with G6PD deficiency--was observed in one case. Levels of white blood cell G6PD activity of the three patients were 0-5% of normal controls. Neutrophil oxidative and bactericidal activities were inherently impaired in the patient with Kostmann's syndrome, but were well preserved in his two siblings.     

组织非特异性碱性磷酸酶基因突变与低磷酸酶血症：2个新突变位点

目的：对2例低磷酸酶血症（HPP）患者及家系进行分析和基因突变检测,拓展国人HPP致病基因库,探讨HPP的致病机制。方法对HPP家系先证者和其父母进行生化指标[血常规、肝肾功能、碱性磷酸酶（ALP）、甲状旁腺素（PTH）、钙、磷等]和骨密度检测。同时对所有研究对象进行alkaline phospatase,live/bone/kidney（ALPL）基因全部12个外显子和外显子内含子交界区直接测序。结果来自家系1的先证者为36岁成年男性,身高131.0cm,体重35.0kg。X线提示多发性胸腰椎骨折和骨盆畸形,生化检测示血清ALP27U/L。测序发现ALPL基因6号外显子532位杂合突变（c.532T＞C）,致ALPL成熟多肽中酪氨酸被组氨酸替代。该先证者母亲身高140.5cm,体重39.5kg,血清ALP30U/L,基因测序证明也是该杂合突变携带者。来自家系2的先证者5岁,其外祖父母为近亲结婚。该患儿身高100.0cm,体重18kg。血清ALP55U/L[低于同龄儿童正常范围（＜10岁）75～344U/L],牙齿发育不良并脱落,有左股骨中下端骨折史。测序发现该患儿存在ALPL基因2个错义突变,其中9号外显子c.871G＞A突变。4号外显子269位突变（c.269A＞G）是一个新的错义突变,该突变导致成熟ALPL多肽中天冬氨酸被甘氨酸所替代。该患儿母亲亦是4号外显子c.269A＞G错义突变携带者,但其生化指标正常,无骨骼和牙齿异常。结论ALPL基因6号外显子c.532T＞C突变和4号外显子c.269A＞G突变是以往未曾报道过的新错义突变,为上述2例HPP患者致病基因。     

A New Exon 9 Glucose-6-phosphate Dehydrogenase Mutation (G6PD “Rehovot”) in a Jewish Ethiopian Family with Variable Phenotypes

ABSTRACTHereditary nonspherocytic hemolytic anemia (HNSHA) is a rare manifestation of glucose-6-phosphate dehydrogenase (G6PD) gene mutations, caused mainly by mutations located in exon 10 of the G6PD gene and less commonly by mutations in other parts of the gene. A new, exon 9, single-base mutation representing a T → C transition at cDNA nucleotide 964 was found in three brothers and their carrier mother of Jewish Ethiopian descent. Biochemical characterization of the resultant protein was not performed. Though clinical manifestations included HNSHA in all cases, the severity of hemolysis and the transfusion requirement differed markedly. Severe congenital neutropenia (Kostmann's syndrome)—a disorder never reported before in conjunction with G6PD deficiency—was observed in one case. Levels of white blood cell G6PD activity of the three patients were 0–5% of normal controls. Neutrophil oxidative and bactericidal activities were inherently impaired in the patient with Kostmann's syndrome, but were well preserved in his two siblings.     

Molecular characterization of glucose-6-phosphate dehydrogenase (G6PD) deficiency in patients of Chinese descent and identification of new base substitutions in the human G6PD gene

The underlying DNA changes associated with glucose-6-phosphate dehydrogenase (G6PD)-deficient Asians have not been extensively investigated. To fill this gap, we sequenced the G6PD gene of 43 G6PD- deficient Chinese whose G6PD was well characterized biochemically. DNA samples were obtained from peripheral blood of these individuals for sequencing using a direct polymerase chain reaction (PCR) sequencing procedure. From these 43 samples, we have identified five different types of nucleotide substitutions in the G6PD gene: at cDNA 1388 from G to A (Arg to His); at cDNA 1376 from G to T (Arg to Leu); at cDNA 1024 from C to T (Leu to Phe); at cDNA 392 from G to T (Gly to Val); at cDNA 95 from A to G (His to Arg). These five nucleotide substitutions account for over 83% of our 43 G6PD-deficient samples and these substitutions have not been reported in non-Asians. The substitutions found at cDNA 392 and cDNA 1024 are new findings. The substitutions at cDNA 1376 and 1388 account for over 50% of the 43 samples examined indicating a high prevalence of these two alleles among G6PD-deficient Chinese. Our findings add support to the notion that diverse point mutations may account largely for much of the phenotypic heterogeneity of G6PD deficiency.     

Novel mutations and sequence variants in exons 3-9 of human T cell factor-4 gene in sporadic rectal cancer patients stratified by microsatellite instability

AIM： To establish the role of human T Cell Factor-4 （hTCF-4） gene exons 3-9 mutation status in association with sporadic rectal cancer with microsatellite instability （MSI）.
METHODS： Microsatellite markers were genotyped in 93 sporadic rectal cancer patients. Eleven cases were found to be high-frequency MSI （MSI-H）. Sequence analysis of the coding region of the exons 3-9 of hTCF-4 gene was carried out for the 11 MSI-H cases and 10 controls （5 microsatellite stability （MSS） cases and 5 cases with normal mucosa）. The sequencing and MSI identification were used.
RESULTS： Several novel mutations and variants were revealed. In exon 4, one is a 4-position continuous alteration which caused amino acid change from Q131T and S132I （391insA, 392 G 〉 A, 393 A 〉 G and 395delC） and another nucleotide deletion （395delC） is present in MSI-H cases （5/10 and 4/10, respectively） but completely absent in the controls.
CONCLUSION： Novel mutations in exon 4 of hTCF-4 gene were revealed in this study, which might be of importance in the pathogenesis of sporadic rectal cancer patients with MSI-H.