A preliminary study of plasma microRNA levels in children with methylmalonic acidemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Plasma 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSIONS</b>Plasma 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.</p>

Genetic polymorphism of methionine synthase reductase in young and middle-aged patients with cerebral infarction / 中华神经医学杂志

Objective To explore the relationship between methionine synthase reductase (MTRR) gene polymorphism and cerebral infarction in young and middle-aged patients. Methods The genotype of MTRR A66G was analyzed by polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) and the plasma homocysteine (Hcy) level was measured by high performance liquid chromatography in 105 young and middle-aged patients with cerebral infarction and 116 age-matched healthy controls. Results The genotype distribution and allele frequencies of MTRR A 66G gene between the 2 groups had no statistical significance (P＞0.05).Stratified analysis,performed according to whether cerebral infarction was complicated with hypertension,diabetes or coronary heart disease,indicated that the frequencies ofGG genotype and G allele in cerebral infarction patients without complications were obviously higher than those in controls (36.4％ vs.23.3％,62.1％ vs.52.2％),but no statistical significance was noted between them (P＞0.05).No statistical difference was observed between cerebral infarction patients with complications and controls (P＞0.05). The mean plasma Hcy level in patients and controls with GG genotype was significantly higher than that in patients and controls with AA genotype (P＜0.05). Conclusion No association between MTRR A 66G polymorphism and cerebral infarction is noted in young and middle-aged patients, while GG mutant homozygous ofMTRR A66G gene can significantly raise the plasma Hcy level.