Child ; Humans ; Hyperhomocysteinemia ; genetics ; Male

Adult ; Epilepsy ; genetics ; Humans ; Hyperhomocysteinemia ; genetics ; Hypogonadism ; genetics ; Intellectual Disability ; genetics ; Male ; White Matter ; pathology

OBJECTIVETo screen out differentially expressed microRNAs (miRNAs) in the plasma of children with methylmalonic acidemia (MMA), to determine the expression of miR-9-1 in plasma and to preliminarily evaluate the significance of miR-9-1 as a biomarker in MMA.

METHODSPlasma was obtained from 17 MMA children, 10 hyperhomocysteinemia (HHcy) children without MMA (HHcy group), and 10 normal controls. Of 17 MMA children, 12 had HHcy (MMA+HHcy group), and 5 had no HHcy (MMA group). The differentially expressed miRNAs were screened out by miRNA microarray. Differentially expressed miR-9-1 was selected, and plasma miR-9-1 levels were determined by RT-PCR. Urine was collected from MMA patients who received vitamin B12 treatment, and plasma miR-9-1 levels were determined by RT-PCR after treatment.

RESULTSThe miRNA microarray analysis showed that 26 miRNAs were differentially expressed, among which 16 miRNAs (including miR-9-1) were down-regulated over 2 times, while 10 miRNAs were up-regulated over 2 times. The MMA+HHcy , MMA and HHcy groups had significantly down-regulated miR-9-1 compared with the normal control group (P<0.01). The patients who showed a good response to vitamin B12 treatment had significantly increased plasma miR-9-1 levels, without significant difference compared with the normal control group.

CONCLUSIONSPlasma miR-9-1 is significantly down-regulated in MMA patients, but it is significantly up-regulated after vitamin B12 treatment, suggesting that miR-9-1 may act as a biomarker in monitoring the progression of MMA.

Adolescent ; Amino Acid Metabolism, Inborn Errors ; genetics ; Child ; Female ; Humans ; Hyperhomocysteinemia ; genetics ; Male ; MicroRNAs ; blood

Adventitia ; Atherosclerosis/genetics* ; Cell Communication ; Humans ; Hyperhomocysteinemia/genetics* ; Sequence Analysis, RNA

OBJECTIVETo study the relationship between the plasma homocysteine (HCY) level and the polymorphism of N(5), N(10)-methylenetetrahydrofolate reductase (MTHFR) gene C667T in liver cirrhosis.

METHODS112 normal subjects and 87 liver cirrhosis patients were recruited in the study. Their plasma HCY levels were measured using high performance liquid chromatography with fluorescence detection and polymorphisms of their MTHFR gene were analyzed using PCR-RFLP.

RESULTSThe mean level of plasma HCY was significantly higher in patients with liver cirrhosis (21.71+/-4.86) micromol/L than that in healthy individuals (8.34+/-3.59) micromol/L. There were three kinds of MTHFR genotypes: +/+ (TT, homozygous mutation), +/- (CT, heterozygous mutation) and -/- (CC, wild type). The frequencies of the three genotypes were as follows: +/+, 29.9%; +/-, 52.9%; -/-, 17.2% in cirrhosis patients and +/+, 19.6%; +/-, 33.9%; -/-, 46.4% in normal subjects. The frequency of homozygous or heterozygous mutation was significantly higher in cirrhosis patients than that in the normal control. Moreover, plasma homocysteine level was markedly higher in patients with MTHFR genetic mutation than those without mutation.

CONCLUSIONSHyperhomocysteinemia may be an independent risk factor for liver cirrhosis. MTHFR is the main enzyme related to homocysteine metabolism. The genetic mutation of MTHFR C667T is possibly an important mechanism of hyperhomocysteinemia in liver cirrhosis. The level of plasma homocysteine may be an early indicator for liver cirrhosis.

Female ; Homocysteine ; blood ; Humans ; Hyperhomocysteinemia ; complications ; genetics ; Liver Cirrhosis ; complications ; genetics ; Male ; Methylenetetrahydrofolate Dehydrogenase (NAD+) ; genetics ; Point Mutation ; Polymorphism, Genetic

Arteriosclerosis and its complications, such as heart attack and stroke, are the major causes of death in developed countries. It was believed that age, hyperlipidemia, hypertension, diabetes and smoking are common risk factors for cardiovascular disease. In addition, overwhelming clinical and epidemiological studies have identified homocysteine (Hcy) as a significant and independent risk factor for cardiovascular disease. In healthy individuals, plasma Hcy is between 5 and 10 micromol/L. One cause of severe hypehomocys- teinemia (HHcy) is the deficiency of cystathionine beta-synthase (CBS), which converts Hcy to cystathionine. CBS homozygous deficiency results in severe HHcy with Hcy levels up to 100 to 500 micromol/L. Patients with severe HHcy usually present with neurological abnormalities, premature arteriosclerosis. It has been reported that lowering plasma Hcy improved endothelial dysfunction and reduced incidence of major adverse events after percutaneous coronary intervention. The mechanisms by which Hcy induces atherosclerosis are largely unknown. Several biological mechanisms have been proposed to explain cardiovascular pathological changes associated with HHcy. These include: (1) endothelial cell damage and impaired endothelial function; (2) dysregulation of cholesterol and triglyceride biosynthesis; (3) stimulation of vascular smooth muscle cell proliferation; (4) thrombosis activation and (5) activation of monocytes. Four major biochemical mechanisms have been proposed to explain the vascular pathology of Hcy. These include: (1) autooxidation through the production of reactive oxygen species; (2) hypomethylation by forming SAH, a potent inhibitor of biological transmethylations; (3) nitrosylation by binding to nitric oxide or (4) protein homocysteinylation by incorporating into protein. In summary, our studies, as well as data from other laboratories support the concept that Hcy is causally linked to atherosclerosis, and is not merely associated with the disease. Although folic acid, vitamin B12 and B6 can lower plasma Hcy levels, the long-term effects on cardiovascular disease risk are still unknown and judgments about therapeutic benefits await the findings of ongoing clinical trials.
Animals ; Atherosclerosis ; etiology ; physiopathology ; Cystathionine beta-Synthase ; deficiency ; genetics ; Homocysteine ; metabolism ; Humans ; Hyperhomocysteinemia ; complications ; physiopathology ; Reactive Oxygen Species ; metabolism

OBJECTIVETo study the clinical features and treatment outcomes of cardiovascular system involvement in children with methylmalonic aciduria combined with hyperhomocysteinemia (MMACHC).

METHODSThe clinical data of 10 children with methylmalonic aciduria combined with hyperhomocysteinemia and who had cardiovascular system involvement were retrospectively analyzed and the treatment outcomes were followed up.

RESULTSIn the 10 patients, there were 4 cases with initial presentations of cardiovascular system symptoms such as shortness of breath and dyspnea, 3 cases with urinary tract symptoms such as edema, hematuria and proteinuria, and 3 cases with nervous system symptoms such as developmental retardation and convulsions. The 10 patients had different types and severity of cardiovascular injuries. After 3 months to 8 years of follow-up, the congenital heart defects resolved naturally in 2 cases, and the patient with arrhythmia had no obvious changes. In 5 cases of hypertension, blood pressures recovered to normal in 3 cases, and 1 case was lost to follow-up. In 5 patients with pulmonary hypertension, 2 died, 2 recovered, and 1 case had mildly elevated pulmonary artery pressure. Seven patients underwent MMACHC gene testing, and 5 showed c.80A>G mutations.

CONCLUSIONSMetabolic disease should be taken into account for the children with unexplained pulmonary hypertension and hypertension with the onset of the shortness of breath and dyspnea. The severity of cardiovascular system involvement might be one of the most important factors affecting the prognosis of children with MMACHC. Cardiavascular system involvement of the patients may be related to MMACHC c.80A>G mutations.

Amino Acid Metabolism, Inborn Errors ; complications ; genetics ; Cardiovascular Diseases ; etiology ; Child ; Child, Preschool ; Female ; Follow-Up Studies ; Humans ; Hyperhomocysteinemia ; complications ; genetics ; Infant ; Infant, Newborn ; Male ; Retrospective Studies

OBJECTIVEMethylmalonic acidemia complicated with homocysteinemia, cblC type, is the most common inborn error of cobalamin metabolism. The gene MMACHC (OMIM 277400) is located on chromosome 1p34.1 with four coding exons and a 5th non-coding exon. It encodes for a protein with 282 amino acid residues. So far, more than 40 mutations have been detected, in which 271dupA (R91KfsX14) is the hot spot of MMACHC gene. However, there have not been relevant reports in China. The present study aimed to identify the mutation types of MMACHC gene and analyze the genotype-phenotype correlations in Chinese patients.

METHODThe diagnosis of this disease mainly depends on the measurement of C3 propionylcarnitine, C3/C0 (free carnitine) and C3/C2 (acetylcarnitine) in the blood by tandem mass spectrometry, the detection of methylmalonic acid in the urine by gas-chromatography mass spectrometry, the determination of total homocysteine in the serum, and the loading test of vitamin B12. The entire coding region of MMACHC gene was screened by polymerase chain reaction (PCR) combined with DNA direct sequencing in 28 Chinese patients. Genomic DNA was extracted using phenol-chloroform method from the peripheral blood leukocytes of each patient. PCR amplification products were checked by 1.8% agarose gel electrophoresis and were subsequently sequenced with both the forward and reverse primers. Mutational analyses were performed using normal human genomic MMACHC sequence as a reference (GenBank ID: 25974).

RESULTIn this study, ten mutations were identified in 27 of 28 Chinese patients. Most of them were located in exons 3 and 4 (91.3%). We detected four mutations reported, which were 609G>A (W203X), 217C>T (R73X), 271dupA (R91KfsX14), and 394C>T (R132X), and six novel mutations, which were 1A>G, 365A>T, 658_660delAAG, 301-3_327del 30, 567_568insT, and 625_626insT. The 609G>A (W203X) is the most common mutation, which was detected in 30 of 56 alleles (53.6%), including 10 homozygote mutations and 10 heterozygote mutations. In addition, three gene polymorphisms were detected, namely, -302T>G (rs3748643), -234A>G (rs3728644), and 321G>A (rs2275276). These mutations include missense mutations, nonsense mutations, duplication, deletions, and insertions.

CONCLUSIONIn this study, we found a part of gene mutations spectrum in Chinese patients with methylmalonic acidemia and homocysteinemia, in which the 609G>A (W203X) may be the hotspot mutation of MMACHC gene. This would be helpful in the prenatal diagnosis and gene screening programs of methylmalonic acidemia and homocystinemia.

Amino Acid Metabolism, Inborn Errors ; complications ; genetics ; Cysteine ; blood ; DNA ; DNA Mutational Analysis ; Exons ; Humans ; Hyperhomocysteinemia ; complications ; genetics ; Methylmalonic Acid ; blood ; Mutation

Hyperhomocysteinemia is known to be associated with an increased risk of myocardial infarction, stroke, peripheral arterial disease, and venous thrombosis. Gene polymorphisms in methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) may account for reduced enzyme activity and hyperhomocysteinemia. A recent study has documented evidence of polygenic regulation of plasma homocyteine. We report here on a case of occlusive stroke at young age and hyperhomocysteinemia with homozygous VN (677C to T) variant in the MTHFR gene as well as homozygous D/D (2756G to A) variant in the MS gene.
5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase/*genetics ; Adult ; Cerebrovascular Accident/*genetics ; DNA/metabolism ; DNA Restriction Enzymes/metabolism ; Family Health ; Female ; Genotype ; Homocysteine/blood/genetics ; *Homozygote ; Human ; Hyperhomocysteinemia/*genetics ; Male ; Polymorphism (Genetics) ; Tetrahydrofolates/*genetics ; Variation (Genetics)

OBJECTIVETo 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.

METHODSTotally 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).

RESULTSThe 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).

CONCLUSIONHyperhomocysteinemia 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