OBJECTIVE: To detect variants of IVD gene among 4 neonates with suspected isovalerate acidemia in order to provide a guidance for clinical treatment. METHODS: 111 986 newborns and 7461 hospitalized children with suspected metabolic disorders were screened for acyl carnitine by tandem mass spectrometry. Those showing a significant increase in serum isovaleryl carnitine (C5) were analyzed for urinary organic acid and variants of the IVD gene. RESULTS: Four cases of isovalerate acidemia were detected, which included 2 asymptomatic newborns (0.018‰, 2/111 986) and 2 children suspected for metabolic genetic diseases (0.268‰, 2/7461). The formers had no obvious clinical symptoms. Analysis of acyl carnitine has suggested a significant increase in C5, and urinary organic acid analysis has shown an increase in isovaleryl glycine and 3-hydroxyisovalerate. Laboratory tests of the two hospitalized children revealed high blood ammonia, hyperglycemia, decreased red blood cells, white blood cells, platelets and metabolic acidosis. The main clinical manifestations have included sweaty foot-like odor, feeding difficulty, confusion, drowsiness, and coma. Eight variants (5 types) were detected, which included c.158G>A (p.Arg53His), c.214G>A (p.Asp72Asn), c.548C>T (p.Ala183Val), c.757A>G (p.Thr253Ala) and 1208A>G (p.Tyr403Cys). Among these, c.548C>T and c.757A>G were unreported previously. None of the variants was detected by next generation sequencing of 2095 healthy newborns, and all variants were predicted to be likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics. CONCLUSION The incidence of isovalerate acidemia in Liuzhou area is quite high. Screening of metabolic genetic diseases is therefore recommended for newborns with abnormal metabolism. The discovery of novel variants has enriched the mutational spectrum of the IVD gene.
Infant, Newborn ; Child ; Humans ; Acidosis ; Carnitine ; Erythrocytes ; High-Throughput Nucleotide Sequencing

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.

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 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

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 analyze variations of TYR and P genes among 14 patients with clinically diagnosed oculocutaneous albinism. Methods: Potential variations of the TYR and P genes were detected by Sanger sequencing. Novel variations were predicted with bioinformatics software including SIFT and PolyPhen-2. Results: No variation was found in the TYR gene, while 9 types of variations were found in the P gene among the 14 patients, which included c. 803-3C>G (7/26), c. 1327G>A (p.Val443Ile) (5/26), c. 632C>T (p.Pro211Leu) (4/26), c. 1832T>C (p.Leu611Pro) (3/26), c. 1349C>A (p.Thr450Lys) (2/26), c. 2363C>T (p.Ser788Leu) (2/26), c. 2228C>T (p.Pro743Leu) (1/26), c. 1525A>G(p.Thr509Ala) (1/26), and c. 1349C>T(p.Thr450Met) (1/26). Only 1 heterozygous variation was detected in 2 families. c. 2363C>T (p.Ser788Leu), c. 1832T>C (p.Leu611Pro) and c. 1525A>G (p.Thr509Ala) were not reported previously and predicted as "harmful" to the protein function. Conclusion The main type of ocular albinism is oculocutaneous albinism type Ⅱ in Liuzhou region, where the most common variations of the P gene were c. 803-3C>G and c. 1327G>A (p.Val443Ile). Above finding has enriched the variation spectrum of the P gene.

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.

OBJECTIVETo screen for carriers of SMN1 gene mutation, which underlies spinal muscular atrophy (SMA), in 4931 pregnant women from Liuzhou region of Guangxi, and to determine the carrier rate.

METHODSCombined denaturing high-performance liquid chromatography (DHPLC) and multiple PCR techniques were used to detect the copy number of SMN1 gene. The carrier frequency was calculated. The spouse of the carrier was also screened, and prenatal diagnosis was provided to the couples who were both positive.

RESULTSAmong the 4931 pregnant women, 61 were found to harbor only one copy of the SMN1 gene, which yielded a carrier rate of 1.2%. Subsequent testing has identified 1 fetus carrying homozygous deletions of the SMN1 gene.

CONCLUSIONThe carrier rate of SMA mutation in Liuzhou region is slightly lower than that of other regions of southern China. DHPLC can effectively screen the carriers of SMA mutation and provide a basis for genetic counseling and prenatal diagnosis.