OBJECTIVE: To detect variants of the MMACHC gene among 110 ethnic Han Chinese pedigrees affected with metabolic deficiency methylmalonic acidemia (MMA) of cobalamin C (cblC). METHODS: Peripheral blood samples were collected from the probands and their parents. Following DNA extraction, the coding regions of the MMACHC gene were subjected to PCR amplification, Sanger sequencing and quantitative PCR assaying. For 48 pedigrees, chorionic villus samples were taken for prenatal genetic diagnosis. RESULTS: Thirty five types of variants were detected among the 110 pedigrees, which included missense, nonsense, frameshifting, splicing variants and exonic deletions. Most variants have occurred in exons 4 (73.18%). The detection rate for c.609G>A (p.Trp203Ter) variant was the highest (33.64%), followed by c.658_660delAAG (12.27%), c.567dupT (9.09%) and c.80A>G (6.82%). Two variants, namely c.57_58insT (p.Gly20Trpfs*14) and c.505_506delAT (p.Ile169Argfs*12), were unreported previously and both were of frameshifting types. For the 48 pedigrees undergoing prenatal diagnosis, 14 fetuses were found to be normal, 24 have carried heterozygous variants, the remaining 10 have carried compound heterozygous or homozygous variants. CONCLUSION The discovery of the two novel variants has expanded the spectrum of the MMACHC gene variants among ethnic Han population. Above finding has provide a basis for the prenatal diagnosis and genetic counseling for the affected pedigrees.
Amino Acid Metabolism, Inborn Errors/genetics* ; China ; DNA ; Female ; Humans ; Mutation ; Oxidoreductases/genetics* ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Vitamin B 12/genetics*

OBJECTIVE: To investigate the genetic etiology, clinical diagnosis and treatment of a child with pancytopenia, failure to thrive and pulmonary infection. METHODS: Peripheral blood samples of the child and her parents were collected. Genomic DNA was extracted. Genetic variants associated with hematological diseases were detected by high-throughput sequencing. RESULTS: Three variants of TCN2 gene were found, one of which located in exon 5 upstream(c.581-8A>T), the parents has carried this variant; one in exon 6 (c.924_927del), the variant was originated from the mother; one in exon 7 (c.973C>T), the variant has ocurred de novo. The variants pathogenic analysis combined with clinical manifestation, pancytopenia, the increase in methylmalonic acid level and increased homocysteine, the child was diagnosed with transcobalaminIIdeficiency. The patient presented with respiratory infection, which was confirmed to be pneumocystosis by lung radioscopy and pathogenic high-throughput sequencing of broncho-alveolar lavage fluid. The patient presented with acute respiratory distress syndrome during the treatment with intramuscular injection of vitamin B CONCLUSION We reported a case of Chinese child with TCNII deficiency due to novel gene variant, and analyzed the pathogenicity of the three variants. The treatment of TCNII deficiency with cobalamin should be individualized.
Amino Acid Metabolism, Inborn Errors ; Child ; Female ; Genetic Testing ; Humans ; Rare Diseases ; Transcobalamins/genetics* ; Vitamin B 12

<b>OBJECTIVEb>To assess the association of transcobalamine II (TCN2) gene polymorphisms and serum levels of homocysteine (Hcy), vitamin Band folate with ulcerative colitis (UC) among Chinese patients.

<b>METHODSb>For 397 UC patients and 574 controls, two single nucleotide polymorphisms of the TCN2 gene (rs1801198, rs9606756) were tested with an improved multiple ligase detection reaction method. Serum Hcy, vitamin Band folate were measured with an enzymatic cycling assay and an chemiluminescence immunoassay, respectively.

<b>RESULTSb>The allelic and genotypic frequencies of rs1801198 and rs9606756 did not differ significantly between the two groups (all P> 0.05). Compared with those of the control group, the frequencies of G allele and CG+GG genotype of rs1801198 were greater in patients with moderate and severe UC (both P< 0.05). The same conclusion may also be drawn for the G allele and AG genotype of rs9606756 (both P< 0.05). Compared with the controls, average Hcy level was enhanced in UC patients (P< 0.01), whereas average vitamin Band folate levels were decreased in UC patients (both P< 0.01). In both groups, the average level of Hcy was lower in individuals carrying CC of (rs1801198) than in those with CG+GG (both P< 0.05). A similar conclusion was also drawn for individuals with AA of rs9606756 when compared with those carrying AG(both P< 0.05). Compared with patients with mild UC, average Hcy level was increased in those with moderate and severe UC (P< 0.01), while average vitamin Band folate levels were decreased in those with moderate and severe UC (both P< 0.01). The prevalence of hyperhomocysteinemia(HHcy), vitamin Bdeficiency and folate deficiency was greater in UC patients than in controls (all P< 0.01). In UC patients, the level of Hcy was negatively correlated with those of vitamin B(P< 0.01), albumin(P< 0.01), red blood cells(P< 0.01) and platelet (P< 0.05), but positively correlated with white blood cells(P< 0.01) and Mayo score (P< 0.01). Both HHcy and folate deficiency were independent risk factors for UC (OR=4.173, OR=5.206, both P< 0.01).

<b>CONCLUSIONb>TCN2 (rs1801198, rs9606756) variations, as well as serum levels of Hcy, vitamin Band folate, are correlated with UC. Both HHcy and folate deficiency are independent risk factors for UC.

Adult ; Colitis, Ulcerative ; blood ; etiology ; genetics ; Female ; Folic Acid ; blood ; Genotype ; Homocysteine ; blood ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Transcobalamins ; genetics ; Vitamin B 12 ; blood

<b>OBJECTIVEb>To analyze mutation types, clinical features, and treatment outcomes of cobalamin C (cblC) type combined methylmalonic aciduria and homocystinuria (MMA-HC) and to investigate the relationship of genotypes with clinical phenotypes and outcomes.

<b>METHODSb>The clinical data of 16 Chinese children diagnosed with cblC type MMA-HC by gene analysis were retrospectively analyzed. According to the onset age, the patients were classified into early onset (≤1 year) and late onset (>1 year). According to the clinical phenotype, the patients were classified into mild, moderate, and severe groups. All the patients were treated with vitamin B12 (cyanocobalamin) or hydroxocobalamin, betaine, folate, vitamin B6, and L-carnitine.

<b>RESULTSb>Fifteen patients belonged to the early onset type, including 11 in the severe group and 4 in the moderate group. The remaining one belonged to the late onset type. Seven reported mutations and two novel mutations (c.445_446delTG and c.349G>c) were detected. The c.609G>A and c.658_660delAAG were the most common mutations detected in 13 (81%) out of 16 patients. The genotype caused by compound heterozygous mutations of these two alleles (c.609 G>A/c.658_660delAAG) was the most common in the patients, detected in 4 (25%) out of 16 patients. Patients with this genotype had severe microcephaly and eye diseases and these clinical manifestations were not improved after the treatment. The patient with late-onset cblC type MMA-HC had normal clinical phenotypes after treatment. In the 15 early onset patients, the more severe the clinical phenotype, the worse the treatment outcome.

<b>CONCLUSIONSb>The cblC type MMA-HC mainly manifests as early onset in China and c.609G >A and c.658_660delAAG are the most common mutations causing this disease. The clinical phenotypes are associated with the outcomes in children with cblC type MMA-HC.

Child ; Child, Preschool ; Female ; Genotype ; Homocystinuria ; genetics ; Humans ; Infant ; Infant, Newborn ; Male ; Mutation ; Phenotype ; Vitamin B 12 Deficiency ; congenital ; genetics

Adult ; Age of Onset ; Amino Acid Metabolism, Inborn Errors ; complications ; diagnosis ; genetics ; therapy ; Betaine ; administration & dosage ; therapeutic use ; Carrier Proteins ; genetics ; metabolism ; Child ; China ; epidemiology ; DNA Mutational Analysis ; Gas Chromatography-Mass Spectrometry ; Genotype ; Homocysteine ; urine ; Humans ; Hydroxocobalamin ; administration & dosage ; therapeutic use ; Hyperhomocysteinemia ; complications ; diagnosis ; genetics ; therapy ; Infant ; Methylmalonic Acid ; blood ; urine ; Mutation ; Vitamin B 12 ; metabolism

<b>OBJECTIVEb>Methylmalonic aciduria is the most common disorder of organic acidurias in the mainland of China. It is also the one of treatable metabolic disorders. The clinical spectrum of the patients varies from severe neonatal-onset forms with neonatal brain injury and high mortality to milder forms with adult-onset. The clinical manifestations of neonates with methylmalonic aciduria are non-specific. Early diagnosis and adequate treatment contribute a lot to improving the prognosis of the patients. In this study, the abnormal clinical and laboratory findings in neonatal period of 160 Chinese patients with early-onset methylmalonic aciduria were investigated.

<b>METHODb>From 1996 to 2011, a total of 398 patients with methylmalonic aciduria were diagnosed in our hospital; 286 (71.9%) patients had early-onset before 1 year of age. Among 286 patients, 160 (55.9%) presented symptoms in neonatal period. Their urine organic acids were analyzed by gas chromatography-mass spectrometry. Blood amino acids and acylcarnitine profiles were determined by liquid chromatography tandem mass spectrometry. Serum and urine total homocysteine were measured using a fluorescence polarization immunoassay. In some patients, gene analysis was performed. Based on the disease types and general condition, individual dietary and medical interventions were started soon after diagnosis.

<b>RESULTb>Out of the 160 patients, 131 (81.9%) had combined methylmalonic aciduria and homocysteinemia. Isolated methylmalonic aciduria was found in 29 cases (18.1%). The common presentations in neonatal period were feeding difficulty, seizures, lethargy and dyspnea. Megaloblastic anemia, liver dysfunction, hyperammonemia and metabolic acidosis were the frequent findings in the routine laboratory test. The most common initial clinical diagnosis was suspected hypoxic-ischemic encephalopathy. Even in 36 cases with abnormal family history, only 3 patients were admitted with suspected inborn errors of metabolism. Five cases (3.1%) were diagnosed by postmortem metabolic examination; 7 cases (4.4%) were detected by newborn screening. In 148 cases (92.5%), the diagnosis was much delayed to the age of one month to 8 years and 5 months (mean 13 months). Methylmalonic aciduria combined with homocysteinemia (MMACHC) gene analyses were performed in 31 cases with combined methylmalonic aciduria. CblC defect was confirmed. The patients with isolated methylmalonic aciduria were treated with protein-restricted diet, cobalamin and L-carnitine. The patients of methylmalonic aciduria combined with homocysteinemia were treated with cobalamin, L-carnitine, calcium folinate, betaine and common diet. Seven patients died without treatment. Clinical improvement was observed in 153 patients. Only 2 patients detected by newborn screening had normal mental and physical development. Mild to severe psychomotor retardation was observed in 151 cases.

<b>CONCLUSIONb>High mortality and disability rates were observed in the patients with early-onset methylmalonic aciduria. Combined methylmalonic aciduria and homocysteinemia is the common type of methylmalonic aciduria. The clinical manifestation in neonatal period of the patients with early-onset methylmalonic aciduria is complex. Feeding difficulty, seizures, lethargy and dyspnea are the common symptoms in neonatal period of the patients. Megaloblastic anemia, liver dysfunction, hyperammonemia and metabolic acidosis were the frequent laboratory findings.

Amino Acid Metabolism, Inborn Errors ; complications ; diagnosis ; genetics ; therapy ; Carnitine ; therapeutic use ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Folic Acid ; therapeutic use ; Gas Chromatography-Mass Spectrometry ; Homocysteine ; blood ; urine ; Humans ; Hyperhomocysteinemia ; diagnosis ; etiology ; therapy ; Infant ; Infant, Newborn ; Male ; Methylmalonic Acid ; urine ; Neonatal Screening ; Retrospective Studies ; Vitamin B 12 ; therapeutic use

<b>INTRODUCTIONb>The functional point mutation C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, has been reported to contribute to hyperhomocysteinaemia which is a risk factor for atherothrombotic ischaemic strokes. This study evaluated the prevalence of the C677T polymorphism of the gene in Malaysian ischaemic stroke subjects of Malay, Chinese and Indian ethnicities, and its association with homocysteine levels (tHcy).

<b>MATERIALS AND METHODSb>A total of 292 subjects were recruited, comprising 150 ischaemic stroke patients and 142 control subjects who were age and sex matched. Plasma homocysteine, serum folate and vitamin B12 were measured in all subjects. Genotyping was carried out using PCR-RFLP.

<b>RESULTSb>The homocysteine levels were significantly higher (P = 0.001) in the stroke group (11.35 ± 2.75 μmol/L) compared to the control group (10.38 ± 2.79 μmol/L). The MTHFR C677T genotype distribution for the stroke group was 46%, 40% and 14%, respectively for CC, CT and TT genotypes and 59.9%, 33.8% and 6.3%, respectively for the control group. The genotype and allelic frequencies were significantly different between the 2 groups, with P = 0.02 and P = 0.004 respectively. No significant difference was seen in the genotype distribution inter-ethnically. An increasing tHcy was seen with every additional T allele, and the differences in the tHcy for the different genotypes were significant in both the control (P <0.001) and stroke groups (P <0.001).

<b>CONCLUSIONb>This study shows that TT genotype of the methylenetetrahydrofolate reductase C677T polymorphic gene is an important determinant for homocysteine levels in Malaysian ischaemic stroke patients.

China ; ethnology ; Ethnic Groups ; genetics ; Female ; Folic Acid ; blood ; Gene Frequency ; Genotype ; Homocysteine ; blood ; genetics ; Humans ; Hyperhomocysteinemia ; complications ; India ; ethnology ; Malaysia ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Point Mutation ; Polymorphism, Genetic ; Stroke ; blood ; genetics ; Vitamin B 12 ; blood

<b>OBJECTIVEb>CblC is the most common type of methylmalonic acidemia with homocysteinemia. MMACHC is the coding gene. This study aimed at understanding clinical features and gene mutations in 2 Chinese pedigrees who had late-onset methylmalonic acidemia complicated with homocysteinemia.

<b>METHODb>The clinical data of 2 cases were analyzed. The MMACHC gene mutation was detected using polymerase chain reaction (PCR) and DNA sequencing.

<b>RESULTb>The age of onset was 13 years and 12 years, respectively. They both presented with nervous system symptoms. The main clinical features were developmental retardation and degradation, including motion, speech and intelligence. One patient complained of anemia. The other patient was misdiagnosed as having a viral encephalitis. Both patients showed remarkable elevation of methylmalonic acid and homocysteine levels in urine. Both had received therapy with vitamin B(12). The symptoms were rapidly relieved. The follow-up till now showed apparent improvement in the 2 cases. Three mutations in the MMACHC gene were found in the two Chinese pedigrees. Both patients were compound heterozygotes of two mutant alleles: one patient had a G-to-A transition at nucleotide 482 (G482A) that caused an arginine-to-glutamine substitution at position 161 of the protein (R161Q), and a deletion of AAG at nucleotide 658_660 (658_660delAAG) which resulted in lysine deleting at position 220 of the protein (K220del); the other patient had a G482A and a G-to-A transition at nucleotide 609 (G609A) that caused a tryptophan-to-termination codon substitution at position 203 of the protein (W203X). Otherwise, the authors also detected parents of two families. Each had a heterozygote of one mutation.

<b>CONCLUSIONb>Late-onset methylmalonic acidemia patients had a variety of clinical manifestation, the first symptom was mainly abnormality of nervous system. One case was accompanied with hematological abnormalities. Two patients were vitamin B(12) responsive. In this study, the mutations were all detected on the fourth exon, the G482A mutation was probably associated with late-onset cases.

Adolescent ; Amino Acid Metabolism, Inborn Errors ; genetics ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Carrier Proteins ; genetics ; Child ; Female ; Humans ; Methylmalonic Acid ; blood ; Mutation ; Pedigree ; Vitamin B 12

<b>OBJECTIVEb>To assess the relationship of methylenetetrahydrofolate reductase (MTHFR) C677T genotypes to unexplained recurrent spontaneous abortion (URSA).

<b>METHODSb>This study included two groups:57 currently non-pregnant women with a history of URSA (URSA group), and 50 currently non-pregnant women with a history of having given birth to at least one live baby and without any history of spontaneous abortion, still-born fetus, placental thrombosis and intrauterine growth retardation(IUGR)(control group). The fasting serum-Hcy was measured with high pressure liquid chromatography. Folic acid and vitamin B(12) were detected by radioimmune assay; antiphospholipid antibody (ACA) was detected by ELISA. MTHFR C677T gene polymorphisms were detected by the technique of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

<b>RESULTSb>C/C genotype in URSA group was significantly lower than that in control group, the total mutant T allele frequency was significantly higher than that in control group. There was no significant difference in respect of "age, rural area/city, period, primary/secondary abortion" between the genotype distributions of MTHFR C677T. The T/T genotype and C/T+T/T genotypes frequencies for "abortion times>or=3" were higher than those for "abortion time <3".

<b>CONCLUSIONb>MTHFR C677T gene polymorphism is a genetic risk factor for URSA.

Abortion, Habitual ; blood ; enzymology ; genetics ; Adult ; Alleles ; China ; DNA Mutational Analysis ; methods ; Female ; Folic Acid ; blood ; Gene Frequency ; Genotype ; Homocysteine ; blood ; Humans ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Point Mutation ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Polymorphism, Restriction Fragment Length ; Vitamin B 12 ; blood

<b>OBJECTIVEb>To study the relationship between plasma homocysteine (Hcy) level and deep-vein thrombosis (DVT), and analyze the interaction of Hcy, folate and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in patients with DVT.

<b>METHODSb>Totally 69 patients with DVT and 111 healthy controls were included in our case-control study. We determined the MTHFR C677T genotypes by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), measured the serum folate and vitamin B12 by radioimmunoassay (RIA), and measured the plasma homocysteine level by fluorescence polarization immunoassay (FPIA).

<b>RESULTSb>The frequency of the MTHFR C677T TT genotype had no significant difference between DVT group and control group (P > 0.05). The plasma Hcy level was significantly higher in DVT group than in control group (13.03 +/- 8.74 mumol/L vs 10.14 +/- 4.30 mumol/L, P < 0.05). Both serum folate and VitB12 of patients with DVT were not significantly different from those of controls. The odds radios (OR) of hyperhomocysteinemia for DVT was 2.53 (95% CI 1.08-5.92). The interaction of low folate level and TT genotype increased the risk of DVT (OR = 3.12, 95% CI 1.17-8.38).

<b>CONCLUSIONb>Hyperhomocysteinemia may be an independent risk factor for DVT in Han nationality, while serum folate level and MTHRF C677T genotype are not. An interaction between serum folate level and MTHFR genotype that affect the Hcy level is an important risk factor for DVT.

Adult ; Aged ; Aged, 80 and over ; Female ; Folic Acid ; blood ; Genetic Predisposition to Disease ; Homocysteine ; blood ; genetics ; Humans ; Hyperhomocysteinemia ; blood ; genetics ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Polymorphism, Restriction Fragment Length ; Venous Thrombosis ; blood ; etiology ; genetics ; Vitamin B 12 ; blood