ObjectivesTo investigate the clinical value of the melting curve analysis-based PCR assay for the clinical genetic diagnosis and prenatal diagnosis of β-thalassemia.Methods A total of 451 peripheral blood samples,including 372 cases with β-thalassemia phenotypes and 79 cases without β-thalassemia phenotypes,were collected by Liuzhou Municipal Maternity and Child Healthcare Hospital between January 2011 and August 2011.Moreover,another 84 cases,including 16 fetal villi samples (10 - 13 weeks),64 amniotic fluid samples (16 -24 weeks ) and 4 umbilical cord blood samples (above 17 weeks),whose parents were β-thalassemia carriers,were also collected for this assay between June 2011 and September 2011.A double-blind test was done to compare the detection reliability of the melting curve analysis-based assay (24 β-thalassemia mutations can be detected) with PCR-RDB probe assay (17 β-thalassemia mutations can be detected ) and DNA sequencing using these samples.The wildtype,mutant and total concordance rates of the genotyping results were calculated separately among the melting curve analysis based assay,PCR-RDB probe assay and DNA sequencing.Results Among the 451 peripheral blood samples,thirteen mutations and nineteen genotypes were obtained by using melting curve analysis-based assay.447 samples had the same detection results and 4 samples had different detection results by comparing melting curve analysis-based assay with PCR-RDB probe assay,thus,the concordance rate of the sample detection result was 99.1％ (447/451),and the concordance rate of the allele detection result was 99.6％ (898/902).DNA sequencing results of the 4 samples showed that 3 samples had the same genotyping result with melting curve analysis-based assay,and 1 sample had the same genotyping result with PCR-RDB probe assay.A rare β-globin mutation which was not included by melting curve analysis-based assay was not detected.Thus,the genotypes of 450 samples were detected accurately by melting curve analysis-based assay,and the concordance rate of the sample detection between the melting curve assay and DNA sequencing assay was 99.8％ (450/451).Among 84 fetal villi,amniotic fluid,and umbilical cord blood samples,8 mutation types and 18 genotypes were obtained by using melting curve analysis-based assay.All the samples have the same detection results by comparing melting curve analysis-based assay with PCR-RDB probe assay and DNA sequencing,so the concordance rate of the genotyping results was 100％ among the melting curve analysis-based assay,PCR-RDB probe assay and DNA sequencing.Conclusions The melting curve analysis-based PCR assay can detect multiple unknown samples simultaneously,and detect multiple mutations accurately.It is very useful for the genetic diagnosis and prenatal diagnosis of β-thalassemia.

Objective To study genotypes in nonsyndromic hearing loss (NSHL ) patients from Guangxi Zhuang Autonomous Region hearing speech rehabilitation center using DNA microarray in combination with Sanger sequencing .Methods Deaf patients received routine physical and otorhinolaryngoloical examinations as well as pure tone autiometry .Brainstem auditory evoked potential test was performed in uncooperative children .Blood samples were obtained from a total of 136 patients ,male 81 ,female 55 ,age from one year five month to seventeen ,having nonsyndromic hearing loss .Genomic DNA was extracted and then 9 hot mutation spots in 4 susceptibility genes were detected by DNA microarray .GJB2 and SLC26A was further detected by Sanger sequencing in the patients with negative results and heterozygotes .Results Among the 136 patients with nonsyndromic hearing loss ,20 cases were positive for GJB2 gene ,SLC26A4 gene or mitochondrial 12SrRNA gene mutations .There were 14 .71% (20/136)patients were positive for hot mutation spots in the deafness related genes ,25% (34/136)patients carried muta‐tions of deafness related genes using DNA microarray in combination with Sanger sequencing .Six SLC26A4 rare mutations (c .259G> T ,c .754C> T ,c .1229C> T ,c .1548_1549insC ,c .1705+5A>G and c .2086C> T) were de‐tected by Sanger sequencing .c .235delC was the most common mutation in GJB2 gene .c .919-2A>G ,c .754C> T and c .1229C> T were the common mutations in SLC26A4 gene .The mutation rate of GJB2 and SLC26A4 was 38 . 24% .and 58 .82% ,respectively .Conclusion Prevalent deafness-associated gene mutations in the nine loci studied were less frequently detected in nonsyndromic hearing loss patients from Guangxi Zhuang Autonomous Region hear‐ing speech rehabilitation center .It can improve the detection rate of deafness gene mutations by using gene microar‐ray in combination with Sanger sequencing .GJB2 and SLC26A4 are the common causative genes .

OBJECTIVE: To screen for potential variants of GCDH gene in 3 patients clinically diagnosed as glutaric aciduria type Ⅰ. METHODS: GCDH gene variants was detected by Sanger sequencing among the three children and their family members. RESULTS: Sanger sequencing showed that patient 1 carried compound heterozygosity variants of c.532G>A (p.Gly178Arg) and c.655G>A (p.Ala219Thr) of the GCDH gene, while his father and mother respectively carried heterozygous c.532G>A(p.Gly178Arg) and c.655G>A (p.Ala219Thr) variants. Patient 2 carried c.532G>A (p.Gly178Arg) and a novel c.1060G>T (p.Gly354Cys) compound heterozygous variant, while his father and mother respectively carried heterozygous c.532G>A (p.Gly178Arg) and c.1060G>T (p.Gly354Cys) variant. Patient 3 carried homozygous c.532G>A (p.Gly178Arg) variant of the GCDH gene, for which both of his parents were heterozygous carriers. CONCLUSION The GCDH gene variant probably underlie the glutaric aciduria type Ⅰ among the 3 patients. Identifcation of the novel variant has enriched the spectrum of GCDH gene variants.
Amino Acid Metabolism, Inborn Errors ; genetics ; Brain Diseases, Metabolic ; genetics ; Female ; Glutaryl-CoA Dehydrogenase ; deficiency ; genetics ; Heterozygote ; Humans ; Male

OBJECTIVE: To explore the molecular pathogenesis for a pedigree affected with hypocalcemia secondary to hypomagnesemia. METHODS: Sanger sequencing was used to detect potential variant of the TRPM6 gene in the patient and their parents. RESULTS: The results showed that the patient has carried novel homozygous c.3311C>T (p.Pro1104Leu) variant of the TRMP6 gene, for which both of his parents were heterozygous carriers. Analysis of protein functions using software predicted high risk of pathogenicity. CONCLUSION The homozygous c.3311C>T (p.Pro1104Leu) variant of the TRPM6 gene probably underlies the disease in this patient.
Heterozygote ; Humans ; Hypocalcemia ; genetics ; Magnesium ; Magnesium Deficiency ; genetics ; Male ; Pedigree ; TRPM Cation Channels ; genetics

Objective: To determine the incidence and mutational types of fatty acid oxidation disorders (FAOD) in central-northern region of Guangxi. Methods: A total of 62 953 neonates were screened for FAOD during December 2012 and December 2017. Acyl-carnitine profiling of neonatal blood sample was performed by tandem mass spectrometry using dry blood spots on a filter paper. The diagnosis of FAOD was confirmed by organic acid profiling of urea and genetic testing. Results: Eighteen cases of FAOD were diagnosed among the 62 953 neonates. Among these, primary carnitine deficiency (PCD) was the most common type (n=13), which was followed by short-chain acyl-CoA dehydrogenase deficiency (SCADD) (n=2), medium- chain acyl-CoA dehydrogenase deficiency (MCADD) (n=1), multiple acyl-CoA dehydrogenase deficiency (MADD) (n=1), and carnitine palmitoyltransferaseⅡdeficiency (CPT ⅡD) (n=1). Genetic testing has revealed two previously unreported variants, i. e., c. 337G>A (p.Gly113Arg) of ACADS gene and c. 737G>T (p.Gly246Val) of ETFA gene. Conclusion PCD is the most common FAOD in central-northern Guangxi. Tandem mass spectrometry combined with genetic testing may facilitate early diagnosis of FAOD.

Objective: To screen for potential variants of GCDH gene in 3 patients clinically diagnosed as glutaric aciduria type Ⅰ. Methods: GCDH gene variants was detected by Sanger sequencing among the three children and their family members. Results: Sanger sequencing showed that patient 1 carried compound heterozygosity variants of c. 532G>A (p.Gly178Arg) and c. 655G>A (p.Ala219Thr) of the GCDH gene, while his father and mother respectively carried heterozygous c. 532G>A(p.Gly178Arg) and c. 655G>A (p.Ala219Thr) variants. Patient 2 carried c. 532G>A (p.Gly178Arg) and a novel c. 1060G>T (p.Gly354Cys) compound heterozygous variant, while his father and mother respectively carried heterozygous c. 532G>A (p.Gly178Arg) and c. 1060G>T (p.Gly354Cys) variant. Patient 3 carried homozygous c. 532G>A (p.Gly178Arg) variant of the GCDH gene, for which both of his parents were heterozygous carriers. Conclusion The GCDH gene variant probably underlie the glutaric aciduria type Ⅰ among the 3 patients. Identifcation of the novel variant has enriched the spectrum of GCDH gene variants.

Objective: To identify potential variant in a child diagnosed as infantile neuroaxonal dystrophy. Methods: Genomic DNA was extracted from peripheral blood samples from the patient and his parents and subjected to next generation sequencing. Suspected variant was verified by PCR and Sanger sequencing. Pathogenicity of the mutation was predicted by using bioinformatic software including SIFT and PolyPhen-2. Results: The child was found to carry compound heterozygous variations c. 668C>A (p.Pro223Gln) and c. 2266C>T (p.Gln756Ter) of the PLA2G6 gene, which were respectively inherited from his father and mother. c. 2266C>T has changed codon 756 (glutamine) into a stop codon, resulting premature termination of peptide chain synthesis. c. 2266C>T has not been reported previously and was predicted to be harmful. Conclusion The compound variants of c. 668C>A (p.Pro223Gln) and c. 2266C>T (p.Gln756Ter) of the PLA2G6 gene probably underlies the disease in the child. Above finding has enriched the variant spectrum of the PLA2G6 gene.

OBJECTIVETo evaluate the clinical value of multicolor melting curve analysis(MMCA) for detecting genetic mutations in G6PD deficiency.

METHODSA total of 402 peripheral blood samples(256 males and 146 females) were collected from suspected patients or their relatives at the Prenatal Diagnosis Center of Liuzhou Maternal and Child Health Hospital between March 2012 and May 2012. The samples were screened by G6PD/6PGD quantitative ratio testing. The reliability of the assay was evaluated by multiplex probe melting curve assay(which can detect 16 G6PD mutations) and DNA sequencing through a double blind study.

RESULTSOne hundred seventy cases with G6PD/6PGD ratio < 1.0 and 232 cases with G6PD/6PGD ratio ≥ 1.0 were detected by the enzymological method. DNA sequencing has identified 182 wild type samples, 151 hemizygous mutation samples, 5 female homozygous mutation samples, 54 female heterozygous mutation samples and 10 female double heterozygous mutation samples. Multicolor melting curve analysis has detected 185 wild type samples, 148 hemizygous mutation samples, 5 female homozygous mutation samples, 55 female heterozygous mutation samples and 9 female double heterozygous mutation samples. The specificity and sensitivity of G6PD gene mutation detection by multicolor melting curve analysis were 100%(182/182) and 98.6%(217/220), respectively. The positive predictive value and negative predictive value were 99.5%(216/217) and 98.4%(182/185), respectively, and the Youden's index was 0.986. The concordance rate of the sample detection between the melting curve assay and DNA sequencing was 99.0%(398/402). Twenty-one different genotypes were detected by the multicolor melting curve analysis and 24 different genotypes were detected by DNA sequencing. Four samples containing mutations(c.196T>A or c.406C>T) were not detected by multicolor melting curve analysis, which can be attributed to different technical settings of the two methods.

CONCLUSIONMulticolor melting curve analysis for G6PD gene mutation detection is a simple, rapid, sensitive and specific method, which can be used for clinical diagnosis of G6PD deficiency.

Adolescent ; Adult ; Child ; Child, Preschool ; Female ; Glucosephosphate Dehydrogenase ; genetics ; Humans ; Infant ; Infant, Newborn ; Male ; Mutation ; Polymerase Chain Reaction ; methods ; Sequence Analysis, DNA

OBJECTIVE: To carry out mutation analysis and prenatal diagnosis for a family affected with primary carnitine deficiency. METHODS: Genomic DNA of the proband was extracted from peripheral blood sample 10 days after birth. The 10 exons and intron/exon boundaries of the SLC22A5 gene were subjected to PCR amplification and Sanger sequencing. The proband's mother was pregnant again two years after his birth. Fetal DNA was extracted from amniocytes and subjected to PCR and Sanger sequencing. RESULTS: Tandem mass spectrometric analysis of the proband revealed low level of plasma-free carnitine whilst organic acids in urine was normal. Compound heterozygous SLC22A5 mutations c.1195C>T (inherited from his father) and c.517delC (inherited from his mother) were detected in the proband. Prenatal diagnosis has detected no mutation in the fetus. The plasma-free carnitine was normal after birth. CONCLUSION Appropriate genetic testing and prenatal diagnosis can prevent further child with carnitine deficiency. The identification of c.517delC, a novel mutation, enriched the spectrum of SLC22A5 mutations.
Cardiomyopathies ; genetics ; Carnitine ; deficiency ; genetics ; Child, Preschool ; DNA Mutational Analysis ; Female ; Humans ; Hyperammonemia ; genetics ; Muscular Diseases ; genetics ; Mutation ; Pregnancy ; Prenatal Diagnosis ; Solute Carrier Family 22 Member 5 ; genetics

OBJECTIVE: To identify potential mutation in a child clinically diagnosed as Noonan syndrome and to provide genetic counseling and prenatal diagnosis for his family. METHODS: Genomic DNA was extracted from peripheral blood samples of the patient and his parents, and amniotic fluid was taken from the mother during the second trimester. Next generation sequencing (NGS) was used to screen potential mutations from genomic DNA. Suspected mutation was verified by Sanger sequencing. RESULTS: A heterozygous c.4A>G (p.Ser2Gly) mutation of the SHOC2 gene was identified in the patient but not among other family members including the fetus. CONCLUSION The Noonan syndrome is probably caused by the c.4A>G mutation of the SHOC2 gene. NGS is helpful for the diagnosis of complicated genetic diseases. SHOC2 gene mutation screening is recommended for patient suspected for Noonan syndrome.
Child ; Female ; Genetic Testing ; High-Throughput Nucleotide Sequencing ; Humans ; Intracellular Signaling Peptides and Proteins ; Mutation ; Noonan Syndrome ; Pregnancy ; Prenatal Diagnosis