BACKGROUND Autism spectrum disorders (ASD) is a heterogeneous neurodevelopmental disease, various articles reported that dysfunctional folate-methionine pathway enzymes might assume a paramount part in the pathophysiology of autism. Methylene tetrahydrofolate reductase (MTHFR) is a basic catalyst for this pathway, also MTHFR gene C677T variant accounted as a risk factor of autism. OBJECTIVE The present study aimed to investigate the association of MTHFR gene rs1801133(C677T) variant among Egyptian autistic children. METHODS The study included 78 autistic children, and 80 matched healthy control children. Full clinical and radiological examinations were conducted. MTHFR genetic variant, rs1801133(C677T) was studied by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods followed by direct sequencing technique. RESULTS MTHFR (C677T) allele frequency was found to be higher significantly in ASD cases compared with nonautistic children. Also, we had a higher distribution of combined CT + TT genotypes among autistic patients with consanguinity and family history of psychological disease. In Gastrointestinal tract (GIT) and sleep disorders showed a higher distribution of hetero CT genotype as well as combined CT + TT genotypes. CONCLUSION This study demonstrated a role of MTHFR gene (C667T) variant with the increased risk for ASD.

中文翻译：

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孤独症谱系障碍埃及儿童中亚甲基四氢叶酸还原酶基因C677T变体的研究。

背景技术自闭症谱系障碍（ASD）是一种异质性神经发育疾病，各种文章报道功能失调的叶酸-蛋氨酸途径酶可能在自闭症的病理生理学中占据重要地位。亚甲基四氢叶酸还原酶（MTHFR）是该途径的基本催化剂，MTHFR基因C677T变异也是自闭症的危险因素。目的本研究旨在研究埃及自闭症儿童中MTHFR基因rs1801133（C677T）变异体的关联。方法该研究包括78名自闭症儿童和80名匹配的健康对照儿童。进行了全面的临床和放射学检查。MTHFR基因变异，使用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法，然后直接测序技术研究了rs1801133（C677T）。结果发现与非自闭症儿童相比，ASD患者的MTHFR（C677T）等位基因频率显着更高。此外，在具有血缘关系和心理疾病家族史的自闭症患者中，组合的CT + TT基因型分布较高。在胃肠道（GIT）和睡眠障碍中，异种CT基因型以及结合的CT + TT基因型分布更高。结论这项研究证明了MTHFR基因（C667T）变体与ASD风险增加有关。在患有血友病和心理疾病家族史的自闭症患者中，CT + TT组合基因型的分布较高。在胃肠道（GIT）和睡眠障碍中，异种CT基因型以及结合的CT + TT基因型分布更高。结论这项研究证明了MTHFR基因（C667T）变体与ASD风险增加有关。在患有血友病和心理疾病家族史的自闭症患者中，CT + TT组合基因型的分布较高。在胃肠道（GIT）和睡眠障碍中，异种CT基因型以及CT + TT组合基因型分布更高。结论这项研究证明了MTHFR基因（C667T）变体与ASD风险增加有关。