G6PD genotype and its associated enzymatic activity in a Chinese population.

Knowledge of the G6PD genotype and its associated enzyme activity is significant for population genetics, diagnosis of disease, and management of patients. We tested 2,872 unrelated subjects from a Hakka population in China for G6PD activity by the WHO standard method and for genotype by DHPLC and DNA sequencing. Among female heterozygotes, 78.5% had relatively normal enzyme activity. The phenotype frequency of G6PD deficiency is 0.028, and the causal allele frequency is 0.060 in females. The accuracy, sensitivity, and specificity of DHPLC are more than 98% for detecting G6PD-deficient hemizygotes, heterozygotes, and homozygotes. Measuring enzyme activity alone is not sufficient for the diagnosis of heterozygotes. A combination of enzyme activity and DNA analysis should be used.

[A new mutation of iduronate-2-sulfatase gene from the patient with Hunter syndrome].

OBJECTIVE: To identify the mutations of iduronate-2-sulfatase (IDS) gene, and to establish a basis of prenatal gene diagnosis of Hunter syndrome. METHODS: Urine glycosaminoglycan (GAG) assay was used to preliminary diagnosis of mucopolysaccharidosis. PCR-denaturing high-performance liquidchromatograptly (PCR-DHPLC) analysis was performed to detect the mutation in exons 9, 3, 8 of the IDS gene. DNA sequencing was applied to analyze the mutation detected by PCR-DHPLC. RESULTS: Abnormal peaks were found by PCR-DHPLC. A new frame-mutation (1569+TT) in exon 9 of IDS gene was identified by DNA sequencing. Two "T"q inserted in position 1569 base pair (1569+TT) caused a substitution of codon 482 (TTA, leucine) to 482 (TTT, phenylalanine). The "TT" insertion results in the decrease of amino acids from 550 to 482. The patient is a hemizygote and his mother is a heterozygote. CONCLUSION: A new frame-shift mutation of IDS gene is found to report. The mutation (1569+TT) results in 68 amino acids lost. Probably it causes the enzyme activity seriously dropped down and being pathologically the basis of disease.

Denaturing high-performance liquid chromatography technique platform applied to screen G6PD deficient variants.

OBJECTIVE: Of denaturing high performance liquid chromatography (DHPLC), a technique platform was developed for screening G6PD deficient variants. METHODS: When applied to screen and identify the G6PD deficient variants from 124 patients who come from 11 nations in China, the DHPLC was compared with amplification refractory mutation system (ARMS) or DNA sequence technique and assessed carefully in its accuracy, sensitivity, efficiency and the cost of experiment. RESULTS: The G6PD-deficient variants, such as 1388 G-->A (36/124 cases), 1376 G-->T(35), 95 A-->G (14), 1024 C-->T (3), 392 G-->T (4), 871 G-->A /1311 C-->T /IVS XI +93 t-->c (9), 871 G-->A (1), 1311 C-->T/IVS XI +93 t-->c (4), 1376 G-->T /1388 G-->A (1) and so on, were characterized as sharp peaks by DHPLC and verified by DNA sequence. Further, the standard chromatograms were put into database for 8 kinds of common G6PD deficient variants in Chinese populations. And also DHPLC found 3 G6PD variants (1388 G-->A) from 103 negative controls. With taking 8.8 minutes and costing 1 dollar for each sample, DHPLC successfully detected and identified 34 heterozygous females from patients with G6PD deficiency. However, ARMS checked 83 positive controls but got 12 false G6PD mutants, of which 5 were false positive, 7 false negative. Above results show that DHPLC sounds like to be more convenience, sensitive and accurate than ARMS and DNA sequence techniques for checking G6PD mutants. CONCLUSION: DHPLC is of great advantage to screen the G6PD deficient variants with accuracy, convenience, automation and less cost, and significantly to identify the female heterozygote and clinical type IV individuals with G6PD deficiency.

[A novel KIT gene mutation from a family with piebaldism in the southern part of China].

OBJECTIVE: To detect the gene mutation of a family with piebaldism. METHODS: Diagnosis of a patient with piebaldism was constructed by pathology, ultrastructural examination and typical clinical-phenotype. Detection of gene mutation was carried out by PCR and DNA sequencing. RESULTS: G 2528A substitution transition in the KIT gene was found in the proband of the family with piebaldism. This mutation resulted in S850N substitution in protein product of KIT gene. No mutation was found in 100 normal individuals and other family members. CONCLUSION: The mutation of S850N maybe one cause of clinical phenotype of the family with piebaldism.

[A novel KIT gene mutation results in piebaldism].

OBJECTIVE: To detect gene mutation in proband and his mother from a family with piebaldism. METHODS: Diagnosis of a patient with piebaldism was validated by pathology, ultrastructural examination and the typical clinical manifestation. PCR and DNA sequencing were carried out to detect gene mutation of a family with piebaldism. RESULTS: G1833A transition in the KIT gene was found in the proband of the family with piebaldism. This mutation resulted in V604I substitution in KIT gene. No mutation was found in 100 normal individuals and other family members. CONCLUSION: The mutation of V604I is the cause of clinical phenotype of the family with piebaldism.

[Identification of G6PD gene variants from Hakka population in Guangdong province].

OBJECTIVE: Studying on G6PD polymorphism from Hakka population in Guangdong province. METHODS: Identifying the variants of G6PD gene and determining the frequencies respectively with the use of amplified refractory mutation system(ARMS), polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) and ABI 3100 DNA sequencing technologies. RESULTS: Mutations of G6PD gene in cDNA 1388 (G-->A), 1376 (G-->T), 95 (A-->G), 392 (G-->T), 1024 (C-->T), 1311 (C-->T) have been found. CONCLUSION: G6PD cDNA 1388 (G-->A), 1376 (G-->T), 95(A--> G), 392 (G-->T), 1024 (C-->T) and 1311 (C-->T) accompanied with intron 11 (93 T-->C) are the common mutations in Chinese population. cDNA 1388 (G-->A), cDNA 1376 (G-->T) are the most popular G6PD gene variants in Hakka population. In this study, no new type of G6PD gene mutation was found in the Hakkas of Guangdong.

[Complex mutations of 1311 C-->T in exon 11 and 93 T-->C in intron 11 in G6PD gene].

OBJECTIVE: To investigate the relationship between complex 1311 mutation of C-->T in exon 11 and 93 T-->C in intron 11 of G6PD gene and the G6PD deficiency. METHODS: Using NBT paper strip method to screen and quantitative NBT method to confirm G6PD deficiency. PCR-SSCP technique was used to find the abnormal exon 11 and the amplification refractory mutation system (ARMS) to identify 1311 mutation, and DNA sequencing to identify the complex mutation at 1311 in exon 11 and 93 in intron 11. RESULTS: Abnormal band in exon 11 was found in 12 cases. DNA sequencing showed that they were 1311 mutation together with 93 mutation. CONCLUSION: This complex mutation may be the cause of reduced activity of G6PD enzyme.

[RFLP of a StuI site in the GALNS gene in Morquio Syndrome of Guangdong national minority population].

To investigate the genetic polymorphism of the StuI site in the GALNS gene from a national minority population in Guangdong and to study the mode of transmission of alleles,PCR-RFLP was used to analyze 144 chromosomes from 72 Guangdong unrelated healthy national minority individuals,and the genotypes of members in three families. To compare the frequencies and heterzygosity between Guangdong national minority people and Caucasians,Japanese and Chinese Han people by using chi2 test. The frequency of allele D1(295bp) was 0.70, allele D2(138 plus 157 bp)0.30, the heterozygosity was 29%. The genotypes of each member of all families detected were completely agreement with the theorical assessment. The site of StuI in the GALNS gene from national minority population in Guangdong has polymorphism. There is significant difference between Guangdong national minority population and Caucasians in Western countries, but no significant difference was found between Guangdong national minority population and Japanese and Chinese Han population. In addition,there is significant difference between Guangdong national minority population and Caucasians and Japanese in the heterzygosity, but no significant difference between Guangdong national minority population and Chinese Han population. The transmission of alleles was completely in agreement with the Mendelian genetic law.