南方医科大学学报 ›› 2021, Vol. 41 ›› Issue (5): 789-792.doi: 10.12122/j.issn.1673-4254.2021.05.22

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表现型为视神经萎缩的NDUFV1基因新移码突变

张智科,袁慧君,张水馨   

  • 出版日期:2021-05-20 发布日期:2021-06-11

A novel frameshift NDUFV1 mutation in a child with the phenotype of optic nerve atrophy

  • Online:2021-05-20 Published:2021-06-11

摘要: 目的 对一个视神经萎缩的儿童进行致病基因研究,并分析其对蛋白结构的影响。方法 收集该患儿及家属病历资料,进行视力、视野、眼底、OCT、VEP等眼科检查,及神经科查体、头颅MRI等全身检查,并随访1年。采集患儿及家长外周血,提取DNA进行全外显子的二代基因测序,并对突变基因进行致病性分析和蛋白结构分析。结果 患儿表现为双眼视力下降、视神经萎缩,VEP呈低振幅,无明显感觉及、肌张力异常,头颅MRI未发现明显脑白质病变。DNA测序显示编码线粒体复合物I(complex I)的核基因NDUFV1基因外显子1中出现杂合的移码突变c.53_54delTG,缬氨酸变为丙氨酸,引起新读码框在20位置过早形成终止编码(p Val18AlafsX20);内含子8中存在杂合的点突变(c.1162+4A>C)。蛋白结构分析显示complex I的NDUFV1亚单元重要结构缺失。结论 在儿童视神经萎缩且无脑白质异常的病例中,发现新的NDUFV1基因突变,有助于拓宽对NDUFV1基因表现型和基因型关系的认识。

关键词: NDUFV1;呼吸酶链复合物I;视神经萎缩;二代基因测序

Abstract: Objective To investigate the pathogenic gene in a child with optic atrophy and analyze the influence of this gene mutation on protein structure. Methods We collected the clinical record of the 13-year-old girl and her relatives. The child received examinations of the visual acuity, visual field, fundus, OCT, visual-evoked potential (VEP) and the nerve system, underwent brain MRI and was followed up for 1 year. Genomic DNA was extracted from the peripheral blood of the child and her parents for next-generation sequencing of the whole exon. The pathogenic gene mutation was identified and the resultant changes in the protein structure was analyzed. Results The patient presented with impaired vision and optic nerve atrophy in both eyes with low amplitude of VEP, but did not show dystonia or pyramidal tract symptom. Brain MRI detected no leukodystrophy. Genetic analysis suggested a heterozygous c.53_54delTG mutation in exon 1 in the NDUFV1 gene of complex I, which caused a frameshift starting with the codon valine 18, thus changing the amino acid to an Alanine residue and creating a premature stop codon at position 20 of the new reading frame (p.Val18AlafsX20). A heterozygous for c.1162+4A>C: IVS8 + 4A>C in intron 8 was also found. Protein structure analysis showed the missing of important structure of NDUFV1 subunit in complex I. Conclusion We identified a novel NDUFV1 mutation in a child with optic nerve atrophy. This finding may provide further insight into the genotype-phenotype correlations for NDUFV1 gene.

Key words: NDUFV1; complex I; optic nerve atrophy; next-generation sequencing