急性淋巴细胞白血病患儿亚甲基四氢叶酸还原酶基因多态性与大剂量甲氨蝶呤不良反应的相关性

目的探讨急性淋巴细胞白血病(ALL)患儿亚甲基四氢叶酸还原酶(MTHFR)基因677位点多态性与大剂量甲氨蝶呤(HDMTX)体内排泄及不良反应的相关性。方法 2008年3月-2010年2月在本院儿科中心和血液内科住院的完全缓解并接受HDMTX治疗的40例ALL患儿,在接受HDMTX治疗前应用PCR-限制性酶切片段长度多态性(RFLP)技术检测MTHFR基因C677T多态性,在HDMTX静脉输注开始后24 h、48 h应用荧光偏振免疫法(FPIA)测定其血浆MTX水平,密切观察ALL患儿HDMTX化疗后的不良反应,对化疗不良反应进行分级。对MTHFR677的基因多态性与MTX不良反应及HDMTX 48 h的MTX水平(MTX-48 h)的相关性进行分析。结果在有HDMTX相关不良反应的ALL患儿中,肝损害和骨髓抑制发生率最高。MTHFR C677T有肝脏损害的基因型分布频率由低到高为CC型40.0%,TT型60.0%,CT型80.0%,CT基因型者肝脏损害发生的风险是CC基因型者的6倍(OR=6.00,95%CI:1.05～34.32,P=0.044);677CT+TT基因型者肝脏损害发生的风险是CC基因型者的4.13倍(OR=4.13,95%CI:1.02～16.67,P=0.047)。MTHFR C677T基因型与骨髓抑制无明显相关性。携有MTHFR突变基因型(CT+TT)患者的48 hMTX血药质量浓度明显高于携带MTHFR野生型基因CC者(P=0.006)。结论 MTHFR 677位基因型可作为ALL患儿HDMTX化疗不良反应和药物体内排泄的有效预测指标。     

亚甲基四氢叶酸还原酶基因多态性与儿童急性淋巴细胞白血病风险的相关性研究

目的 探讨中国汉族儿童亚甲基四氢叶酸还原酶(MTHFR)基因的单核甘酸多态(MTHFR 677C→T及1298 A→C突变)对儿童急性淋巴细胞白血病(ALL)发病风险的影响.方法 收集176例ALL患儿以及与其匹配的170例对照者外周血,通过多重单碱基延伸反应(SNaPshot SNP分型技术)检测MTHFR C677T和A1298C基因型.结合临床资料,比较不同基因型对儿童ALL发病风险的影响及与临床危险度的相关性.结果 MTHFR C677T位点和MTHFR A1298C位点的各基因型在病例组与对照组间分布差异无统计学意义.兼具二种突变的基因型677CT/1298AC分布频率在病例组与对照组间分布差异无统计学意义.MTHFR C677T基因多态性在临床危险度分型及复发组中分布差异有统计学意义.MTHFR 677基因型TT在标危组中占43.0%,高于中危、高危及复发组的频率(P ＜ 0.01).MTHFR 677基因型CC在标危组中占24.0%,低于中危、高危及复发组的频率(P ＜ 0.05).结论 MTHFR 677基因型与儿童ALL的临床危险度分型和复发相关.MTHFR基因677C→T突变可能对中国儿童ALL有一定保护性作用.     

5，10-亚甲基四氢叶酸还原酶基因C677T多态性与先天性心脏病关系的Meta分析

摘要 目的 对5,10 亚甲基四氢叶酸还原酶（MTHFR）基因C677T多态性与先天性心脏病（CHD）的相关性研究进行Meta分析。方法 制定原始文献的纳入标准及检索策略,检索PubMed、EMBASE、Ovid、Springer、中国期刊全文数据库、维普中文科技期刊数据库、万方数据库和中国生物医学文献数据库（1994年1月至2009年1月）中的文献,收集MTHFR基因C677T多态性与CHD相关性的病例 对照研究,剔除不符合要求的文献,应用RevMan 4.2软件进行Meta分析,得出合并后的OR值及其95％CI。结果 共18篇文献符合纳入标准进入Meta分析。数据合并结果显示,子代MTHFR基因 677位点TT/CC和(TT+CT)/CC与CHD易感性有统计学意义,OR值（95％CI）分别为1.55（1.24~1.93）和1.23（1.06~1.42）,P<0.05;子代MTHFR基因677位点CT/CC与CHD易感性无统计学意义,OR值（95％CI）为1.15（0.99~1.34）,P>0.05。父亲MTHFR基因677位点TT/CC和(TT+CT)/CC与子代CHD的易感性有统计学意义,OR值（95％CI）分别为1.84（1.23~2.74）和1.33（1.04~1.71）,P<0.05;父亲MTHFR基因677位点CT/CC与子代CHD易感性无统计学意义,OR值（95％CI）为1.25（0.96~1.62）,P>0.05 。母亲MTHFR基因677位点TT/CC、CT/CC和(TT+CT)/CC与子代CHD易感性均无统计学意义,OR值（95％CI）分别为1.20（0.92~1.56）、1.03（0.86~1.24）和1.07（0.90~1.27）,P均>0.05。传递不平衡分析未发现在CHD核心家系的MTHFR基因677位点存在突变的传递不平衡现象,OR值为0.90（95％CI：0.79~1.12）,P>0.05。结论 子代MTHFR基因677位点TT和TT+CT为CHD的危险因素之一;父亲MTHFR基因677位点TT和TT+CT是子代CHD的危险因素之一;母亲MTHFR基因677位点多态性与子代CHD的发生无关。     

支气管哮喘患儿亚甲基四氢叶酸还原酶基因多态性与血清免疫球蛋白E的关系

目的探讨支气管哮喘(哮喘)患儿亚甲基四氢叶酸还原酶(MTHFR)基因C677位点多态性与血清IgE水平的相关性。方法选择95例哮喘患儿作为病例组,均为急性发作期或临床缓解期哮喘患儿,患病前2周均未使用过肾上腺皮质激素及免疫调节剂。另选择健康儿童113例作为健康对照组。2组儿童年龄及性别比较差异均无统计学意义。采用PCR-限制性片段长度多态性分析法对病例组和健康对照组儿童外周血白细胞MTHFR基因C677位点基因多态性进行研究,应用双抗体夹心ELISA法检测2组儿童血清总IgE水平。结果健康对照组MTHFR 677C/T的3种基因型频率分别CC 35.4%、CT 45.1%、TT 19.5%,病例组分别为CC 24.2%、CT 40.0%、TT 35.8%,677C/T基因型分布频率在哮喘病例组和健康对照组间差异有统计学意义(χ2=7.556 5,P<0.05)。病例组T等位基因的频率为55.3%,健康对照组为42.0%,病例组较健康对照组显著增高,其患哮喘的危险度是健康对照组的1.71倍(χ2=7.254 7,P<0.01;95%CI:1.13～2.57)。病例组血清总IgE水平在各基因型患儿间比较差异有统计学意义(F=3.46,P<0.05),健康对照组血清总IgE水平在各基因型儿童间比较差异无统计学意义(F=0.13,P>0.05)。结论 MTHFRC677位点C→T的基因突变增加了患儿哮喘发病的危险度,TT基因型与哮喘的发生直接相关;哮喘患儿血清总IgE水平升高,该位点基因型并非导致血清总IgE水平升高的直接原因。     

MTHFR基因多态性与儿童原发性高血压的相关性研究北大核心CSCD

目的分析原发性高血压儿童亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因C677T多态性分布特征,探讨其与儿童H型高血压的相关性。方法回顾性选取2021年1~7月于心血管内科住院、初次诊断未经治疗的121例原发性高血压儿童为研究对象,按基因型分为CC型组(19例)、CT型组(51例)和TT型组(51例);按血清同型半胱氨酸(homocysteine,Hcy)水平分为H型高血压组(47例)和单纯高血压组(74例),比较各组间临床资料差异,分析MTHFR基因C677T多态性与儿童H型高血压的相关性。结果原发性高血压儿童T等位基因突变频率高于北京地区健康成年人群和中国汉族成年人群(P<0.001)。TT型组血清Hcy水平高于CC型组和CT型组(P<0.001)。H型高血压组血清Hcy水平高于单纯高血压组(P<0.001),且MTHFR基因C677T多为TT基因型,TT基因型与H型高血压的发生风险存在关联(OR=12.71,P<0.001)。H型高血压组和单纯高血压组间靶器官损伤发生率差异无统计学意义(P>0.05),但初次诊断时,H型高血压组即可存在多脏器受累情况,占11%(5/47)。结论原发性高血压儿童MTHFR基因C677T的T等位基因突变率高且与血清Hcy水平具有一定关联,TT基因型是儿童H型高血压的独立危险因素,与早期靶器官损伤严重程度可能相关。     

MTHFR C677T基因多态性与儿童法洛四联症相关性的meta分析

目的探讨5,10-亚甲基四氢叶酸还原酶(MTHFR)基因多态性(C677T)与儿童法洛四联症的相关性。方法检索Pub Med、中国知网、万方和维普数据库,收集2017年7月以前发表的MTHFR基因多态性(C677T)与儿童法洛四联症病例的对照研究文献,根据纳入和排除标准,剔除不符合要求的文献,行Hardy-Weinberg遗传平衡检验后进行meta分析,并采用序贯试验分析(TSA)方法对结果进行检验。结果共有7篇文献纳入分析,包括1 222例法洛四联症患儿和1 443例对照儿童。Meta分析结果显示,MTHFR基因多态性(C 677 T)位点等位基因模型(T对C)合并后的总OR值为1.63,95%CI:1.41～1.88;显性基因模型(TT+TC对CC)合并后的总OR值为1.67,95%CI:1.34～2.10;隐性基因模型(TT对TC+CC)合并后的总OR值为2.08,95%CI:1.64～2.63;共显性杂合子基因模型(TC对CC)合并后的总OR值为1.36,95%CI:1.07～1.74;共显性纯合子基因模型(TT对CC)合并后的总OR值为2.56,95%CI:1.92～3.41。结论 MTHFRC 677 T基因多态性位点可增加法洛四联症风险。     

白细胞介素-4基因C-589T多态性与呼吸道合胞病毒毛细支气管炎发病的相关性

目的 探讨白细胞介素-(IL-4)基因C-589T位点多态性与呼吸道合胞病毒(RSV)毛细支气管炎发病的相关性.方法 采用聚合酶链-限制性片段长度多态法(PCR-RFLP)检测RSV毛细支气管炎组(毛支组)和健康对照组儿童IL-4/C-589T位点多态性;用化学发光法和酶联免疫分析法(ELISA)分别检测RSV毛支组血清总IgE和鼻咽分泌物(NPS)中IL-4水平.结果 二组均发现IL-4/C-589T位点基因多态性,但仅见TT和CT 2种基因型,以TT纯合子基因型为主,其中RSV毛支组IL-4/C-589T位点TT、CT基因型频率分别为94.6%、5.4%,T、C等位基因频率分别为97.3%、2.7%;对照组TT、CT基因型频率分别为76.9%、23.1%,T、C等位基因频率分别为88.4%、11.6%.RSV毛支组TT基因型和T等位基因频率均显著高于对照组(χ2=15.995,14.842 Pa＜0.01),且T等位基因携带者患病的危险性为C等位基因携带者的4.73倍(OR=4.73 P=0).但2种基因型RSV毛支患儿间NPS中IL-4及血清总IgE水平均无显著性差异(Z=0.515,t=0.260 Pa＞0.05).IL-4/C-589T位点多态性在轻度和中重度患儿间无显著差异(χ2=0.024 P＞0.05).结论 温州地区儿童存在IL-4/C-589T位点的多态性.IL-4/C-589T 位点T等位基因可能是影响RSV毛细支气管炎发病的一个重要候选基因.     

闽南地区急性淋巴细胞白血病患儿亚甲基四氢叶酸还原酶基因多态性与甲氨蝶呤的相关性北大核心CSCD

目的研究亚甲基四氢叶酸还原酶(MTHFR)基因C677T及A1298C位点多态性与闽南地区儿童急性淋巴细胞白血病(ALL)化疗用药甲氨蝶呤(MTX)不良反应易感性的相关性。方法选取2015年1月至2018年6月厦门大学附属第一医院儿科收治的128例闽南地区ALL患儿,采集其外周血2 mL,提取基因组DNA,采用聚合酶链反应(PCR)直接测序方法检测MTHFR基因C677T和A1298C基因型,依据国立癌症研究所毒性判定标准评估ALL患儿MTX不良反应。结果128例患儿中,54例(42.2%)出现皮疹,48例(37.5%)出现黏膜损害,51例(39.8%)出现肝损害,23例(18.0%)出现肾损害,52例(40.6%)出现胃肠道反应,38例(29.7%)出现白细胞减少,34例(26.6%)出现血小板减少,63例(49.2%)出现血红蛋白下降。MTHFR C677T和A1298C基因不同基因型组的MTX化疗不良反应(皮疹、黏膜损害、肝肾损害、胃肠道反应、白细胞减少、血红蛋白下降和血小板减少)的发生率比较差异均无统计学意义(均P>0.05)。患儿不同临床危险度(MTX剂量)分组在MTHFR C677T和A1298C的基因型和等位基因频率中分布差异无统计学意义(χ^2=2.573、2.264、1.615、0.267,均P>0.05)。24 h、48 h和72 h MTX血药浓度异常发生率差异无统计学意义(均P>0.05)。结论MTHFR的C677T和A1298C多态性可能不是预测闽南地区儿童ALL MTX化疗的良好指标,其临床应用仍需进一步探讨。     

急性淋巴细胞白血病患儿MTHFR基因多态性与大剂量甲氨蝶呤毒副反应的关系

目的：探讨亚甲基四氢叶酸还原酶（MTHFR）基因单核苷酸多态性对急性淋巴细胞白血病（ALL）患儿使用大剂量甲氨蝶呤（HD-MTX）化疗后毒副反应的影响。方法：应用RT-PCR-变性梯度凝胶电泳结合DNA测序技术,对52例ALL患儿MTHFR C677T、A1298C和G1793A基因型进行检测。按照国立癌症研究所常规毒性判定标准（NCI-CTC）对患儿HD-MTX化疗后的不良反应统一评价。结果：MTHFR 1298AC基因型患儿发生血小板减少的风险较AA型提高了13.7倍（OR=13.7,95%CI=1.18～159.36,P=0.036）。MTHFR C677T和G1793A各基因型发生各类HD-MTX化疗不良反应的差异无统计学意义（P>0.05）。结论：MTHFR A1298C多态性可能与ALL患儿HD-MTX化疗后的毒副反应相关。     

早发型亚甲基四氢叶酸还原酶缺陷症 1 例临床及基因分析

目的探究MTHFR基因突变引起的亚甲基四氢叶酸还原酶缺陷患儿的临床特点、治疗及预后。方法回顾分析1例MTHFR缺陷导致癫痫、脑积水患儿的临床资料和MTHFR基因检测结果,并复习相关文献。结果女性患儿生后第10天出现抽搐、呼吸不规律、喂养困难、肌张力低下,血同型半胱氨酸水平明显升高(147.9μmol/L);基因测序示MTHFR基因存在复合杂合突变(c.1319_c.1320 insTT,c.1262 GA),其中c.1319_c.1320 insTT以往未见报道。予甜菜碱、亚叶酸钙、维生素B_6、维生素B_(12)治疗2周后,患儿血清总同型半胱氨酸水平下降,临床症状好转,但随后一个月内出现明显脑积水,精神运动发育明显迟缓。结论早发型亚甲基四氢叶酸还原酶缺陷患儿可在生后早期即有表现,血同型半胱氨酸测定及基因检测有助于早期诊断和干预。     

Analysis of MTHFR 1298A>C in addition to MTHFR 677C>T polymorphism as a risk factor for neural tube defects in the Turkish population

Maternal folic acid intake in the periconceptional period is strongly related to reduction in recurrence and occurrence of birth defects involving the neural tube. Among the single nucleotide polymorphisms (SNPs) influencing the folate metabolism, the methylenetetrahydrofolate reductase (MTHFR) gene has been the one most exclusively studied. Many studies have reported significant association between MTHFR 677C>T and increased risk of neural tube defects (NTDs). Our previous study did not support this observation. The present study aimed to determine the prevalence of 1298A>C polymorphism in addition to 677C>T in the same Turkish population as a risk factor for NTDs. We genotyped case (95 offspring with NTDs, 80 mothers, 72 fathers) and control (93 healthy children) populations for MTHFR 677C>T and MTHFR 1298 A>C polymorphisms. The comparison demonstrated a significant increase in the 1298AA/677TT genotype frequency among mothers of offspring with NTDs (OR 5.23 [1.06-25.9]; p=0.067). The 677CT genotype was only 1.35 times higher than controls among mothers when 677C>T polymorphism was evaluated alone, while 677CT/1298AC in the current study demonstrated a 3.8 times increase in this risk. These observations led us to conclude that although not statistically significant, MTHFR 1298AC polymorphism might be a risk factor for the occurrence of NTDs in the Turkish population.     

Reduced total plasma homocyst(e)ine in children and adolescents with type 1 diabetes

OBJECTIVES: The objective was to investigate total plasma homocyst(e)ine (tHcy), methylenetetrahydrofolate reductase (MTHFR) genotype, and the contribution of diet to homocysteine values in children and adolescents with type 1 diabetes and a control group. STUDY DESIGN: A total of 78 children with type 1 diabetes and 59 members of an age- and sex-matched control group were recruited. Fasting samples were collected for tHcy, MTHFR genotype, serum vitamin B(12), serum folate, red cell folate, and plasma creatinine. Food frequency questionnaires targeted intake of folate, vitamin B(6), and vitamin B(12). RESULTS: Fasting tHcy was reduced in patients compared with the control group (4.7 vs 5.9 micromol/L, P <.001). Serum folate (P =.002), red cell folate(P <.001), and serum vitamin B(12) (P =.005) were higher, and plasma creatinine was lower. A significant difference in tHcy values between patients and the control group persisted after correction was done for these factors (r = 0.1, P =.02). No difference was seen in the frequency of MTHFR polymorphisms. tHcy was not elevated in those patients with the 677TT or 677T/1298C genotypes, although red cell folate was significantly higher in members of the case (P =.01) and control groups (P =.05) with a 677 TT genotype. Dietary intake of folate correlated with serum folate (r = 0.4,P =.005). CONCLUSION: tHcy values are lower in children and adolescents with type 1 diabetes. Higher serum levels of folic acid and vitamin B(12), reflecting differences in dietary intake between children with diabetes and members of a control group, partially account for this difference.     

Polymorphism 677C→T MTHFR Gene in Mexican Mothers of Children With Complex Congenital Heart Disease

Congenital heart defects (CHD) are the third leading cause of death in children <1 year of age in Mexico where there is a high prevalence of the 677C→T polymorphism of the MTHFR gene. This is important because the homozygous 677T/T MTHFR gene and deficiency of folic acid (FA) intake have been associated with CHD. Our objective was to analyze the possible association between the genotype 677T/T of the MTHFR gene and supplementation of FA in Mexican women with the presence of complex CHD in their children. We analyzed genotypes of 31 mothers of children with complex CHD (group I) and 62 mothers of healthy children (group II) and investigated FA supplementation during pregnancy in both study groups. Allele frequencies in group I were 41.9 % for C and 58.1 % for T and 22.6 % for genotype frequencies CC, 38.7 % for CT, and 38.7 % for TT. Allele frequencies in group II were 63.7 % for C and 36.3 % for T and 38.7 % for genotype frequencies CC, 50 % for CT and 11.3 % for TT. Both populations are in Hardy–Weinberg equilibrium. Odds ratio for having a child with a complex CHD was 5.9, p = 0.008 (95 % CI 1.67; 20.63) for the TT genotype. FA supplementation at any time during pregnancy was 90.3 and 87.9 % in groups II and I respectively (p > 0.05). Association was found between the maternal genotype (677/TT MTHFR) with the presence of complex CHD in their offspring. No differences in FA supplementation during any stage were found between groups.     

儿童特发性间质性肺疾病与肺表面活性物质-B基因多态性的相关性研究

目的 探讨肺表面活性物质(surfactant protein,SP)-B外显子4(T131I)位点的基因多态性与儿童特发性间质性肺疾病的相关性.方法 收集2013年10月至2016年9月在深圳市儿童医院和广西医科大学附属第一医院住院诊断为特发性间质性肺疾病的患儿共67例为病例组,选择同期与特发性间质性肺疾病无关的因呼吸道感染在深圳市儿童医院住院的102例患儿为对照组,采用SP-B全外显子和侧翼区高通量测序法对所有病例采集的标本进行检测,分析外显子4(T131I)位点的基因型和等位基因分布.结果 病例组和对照组SP-B基因外显子 4(T131I)位点的基因型均可检出3 种,CC、CT及TT型,病例组所占比例分别为67.16%、25.37%、7.46%,对照组分别为56.86%、35.29%、7.84%,两组基因型分布的差异无统计学意义(χ2=1.981,P=0.371);病例组C等位基因频率为79.85%,对照组为74.51%,差异无统计学意义(χ2=1.288,P=0.256).对照组SP-B基因外显子 4(T131I)位点的基因突变频率为43.14%(44/102),与人类基因组千人人群数据库基因突变频率平均值52.00%比较,差异无统计学意义(P>0.05);与欧洲千人人群数据库基因突变频率53.88%、南亚千人人群数据库基因突变频率45.50%和美洲整体人群数据库基因突变频率41.93%比较,差异无统计学意义(P>0.05),而与东亚千人人群数据库基因突变频率26.39%和非洲千人人群数据库基因突变频率80.18%比较,差异有统计学意义(P<0.05).结论 SP-B 基因外显子4(T131I)位点的基因多态性与儿童特发性间质性肺疾病易感性不存在相关性,外显子4(T131I)位点的基因突变频率与种族人群和地域具有一定的差异性.     

C677T mutation in methylenetetrahydrofolate reductase gene and neural tube defects: Should Japanese women undergo gene screening before pregnancy?

We analyzed the role of maternal C677T mutation in methylenetetrahydrofolate reductase (MTHFR) gene on spina bifida development in newborns. A total of 115 mothers who had given birth to a spina bifida child (SB mothers) gave 10 mL of blood together with written informed consent. The genotype distribution of C677T mutation was assessed and compared with that of the 4517 control individuals. The prevalence of the homozygous genotype (TT) among SB mothers was not significantly different from that among the controls (odds ratio [OR] = 0.65; 95% confidence interval [CI] = 0.31–1.25; P = 0.182), suggesting that MTHFR 677TT genotype in Japan is not associated with spina bifida development in newborns. The T allele frequency was not increased in SB mothers (34.8%) as compared to that of the control individuals (38.2%). Further, the internationally reported association between the two groups was found to be similar in all 15 countries studied except the Netherlands, where the TT genotype was found to be a genetic risk factor for spina bifida. For the prevention of affected pregnancy every woman planning to conceive has to take folic acid supplements 400 μg a day and the government is asked to take action in implementing food fortification with folic acid in the near future. In conclusion, it is not necessary for Japanese women to undergo genetic screening C677T mutation of the MTHFR gene as a predictive marker for spina bifida prior to pregnancy, because the TT genotype is not a risk factor for having an affected infant.     

Nitric oxide synthase gene polymorphisms in children with minimal change nephrotic syndrome

Aims:  Nitric oxide (NO) attenuates many functions within the kidney, and all NO synthase (NOS) isoforms are constitutively expressed in the kidney. But the exact role of NO in renal diseases is still debatable. The aim of the present study was to investigate endothelial ( eNOS ), and neuronal ( nNOS ) NOS gene polymorphisms in children with minimal change nephrotic syndrome (MCNS).
Materials and methods:  Eighty-six Turkish children with clinical MCNS, ranging in age from 2 to 10 years, were compared with 114 healthy age- and sex-matched controls. The glu 298 Asp (G/T) polymorphism of the eNOS, and C276T (C/T) polymorphism of nNOS genes were genotyped using polymerase chain reaction.
Results:  The distribution of GG, TG, and TT genotypes for eNOS was 52%, 33% and 15% in MCNS compared with 61%, 26% and 13% in the controls ( P  > 0.05). The distribution of CC, TC, and TT genotypes for nNOS was 16%, 66% and 18% in MCNS compared with 10%, 43% and 47% in the controls. TT genotype distribution of nNOS was found to be lower in patients ( P  = 0.003). The eNOS and nNOS gene polymorphisms were not associated with gender, positive family history, frequency of relapses, or response to steroid.
Conclusions:  The present study is the first to investigate eNOS and nNOS gene polymorphisms in children with MCNS. The nNOS gene polymorphism may be associated with MCNS in children, but further studies in a larger population with different glomerular diseases are needed to confirm the results.