Rahman Molie, Noman Abdullah Al, Saba Abdullah Al, Adiba Maisha, Hasan Md Mahbub, Yasmin Tahirah, Ahmed Bulbul, Ebihara Akio, Nabi A H M Nurun
Laboratory of Population Genetics, Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, 1000, Bangladesh.
Child Development Center, BIRDEM Women and Children Hospital, Shegunbagicha, Bangladesh.
Biochem Genet. 2025 Jun 1. doi: 10.1007/s10528-025-11137-9.
Autism spectrum disorder (ASD) is a complex and multifaceted neurodevelopmental disorder that is becoming more common worldwide. While there is growing evidence linking mitochondrial dysfunction to ASD, the exact causes remain unclear. There is little study being done in Bangladesh on the genetic and biochemical causes of ASD. The goal of this study is to identify mitochondrial DNA (mtDNA) variants in the ND2 gene and explore how these variations might be linked to the progression of ASD and biochemical parameters. Eighty children aged 2-10 years were enrolled, comprising 50 ASD children and 30 healthy controls. Biochemical parameters (lactic acid, ammonia, ALT, AST, calcium, magnesium, TSH, vitamin D, and free thyroxine or FT4) were tested, and mtDNA was extracted and amplified for Sanger sequencing. Identified single nucleotide polymorphisms (SNPs) were evaluated for association with disease outcome and biochemical parameters. Bioinformatics tools were used to analyze the impact of SNPs on protein structure and function. The findings demonstrated significant differences in lactic acid, ammonia, ALT, AST, vitamin D, and FT4 levels between the ASD and control groups (p < 0.05). Lactic acid (AUC = 0.993) showed the highest diagnostic accuracy, while ammonia (AUC = 0.899), AST (AUC = 0.884), and vitamin D (AUC = 0.863) showed excellent performance. A total of 37 SNPs were identified in the ND2 gene, three were novel, with 4901 A>G, 5124 C>A, and 5306 C>T. No variant was found to be associated with disease outcome. However, variants located at 5108 T>C, 5262 G>A, 4703 T>C, 4841 G>A, and 5186 A>T were found to be significantly associated with the altered levels of ammonia, vitamin D and FT4, respectively. Among three novel variants, two were synonymous SNPs (4901 A>G and 5306 C>T) and they showed decreased RSCU values, indicating lower efficiency and affect gene expression. Three variants were identified within the tRNA specific for Q and M but they were predicted to be likely benign. Comprehending the association of these genetic variations and biochemical markers with ASD should facilitate early detection and subsequent management strategy in children with these neurodevelopmental disorders.
自闭症谱系障碍（ASD）是一种复杂且多方面的神经发育障碍，在全球范围内正变得越来越普遍。虽然越来越多的证据将线粒体功能障碍与ASD联系起来，但确切原因仍不清楚。孟加拉国针对ASD的遗传和生化原因开展的研究很少。本研究的目的是鉴定ND2基因中的线粒体DNA（mtDNA）变异，并探讨这些变异如何与ASD的进展及生化参数相关联。招募了80名2至10岁的儿童，其中包括50名ASD儿童和30名健康对照。检测了生化参数（乳酸、氨、谷丙转氨酶、谷草转氨酶、钙、镁、促甲状腺激素、维生素D和游离甲状腺素或FT4），提取并扩增mtDNA用于桑格测序。评估所鉴定的单核苷酸多态性（SNP）与疾病结局和生化参数的关联。使用生物信息学工具分析SNP对蛋白质结构和功能的影响。研究结果表明，ASD组和对照组之间的乳酸、氨、谷丙转氨酶、谷草转氨酶、维生素D和FT4水平存在显著差异（p < 0.05）。乳酸（AUC = 0.993）显示出最高的诊断准确性，而氨（AUC = 0.899）、谷草转氨酶（AUC = 0.884）和维生素D（AUC = 0.863）表现出色。在ND2基因中总共鉴定出37个SNP，其中3个是新的，分别为4901 A>G、5124 C>A和5306 C>T。未发现变异与疾病结局相关。然而，位于5108 T>C、5262 G>A、4703 T>C、4841 G>A和5186 A>T的变异分别被发现与氨、维生素D和FT4水平的改变显著相关。在三个新变异中，两个是同义SNP（4901 A>G和5306 C>T），它们的相对密码子使用度（RSCU）值降低，表明效率较低并影响基因表达。在特定于Q和M的tRNA内鉴定出三个变异，但预计它们可能是良性的。了解这些基因变异和生化标志物与ASD的关联应有助于对患有这些神经发育障碍的儿童进行早期检测及后续管理策略。
