摘要目的:确定并观察1个汉族Leber先天性黑矇（LCA）家系的致病基因变异和临床表型。方法:回顾性研究。2022年5月在河南省立眼科医院就诊的LCA10型一家系（1例患者和2名家系成员）纳入研究。详细询问患者病史、家族史并行眼底彩色照相、闪光视网膜电图（F-ERG）检查。采集先证者及其父母的外周静脉血3 ml，提取全基因组DNA。全外显子组测序（WES）、线粒体环基因组（mtDNA）测序以获得致病基因及变异。通过生物信息学分析方法对所有变异位点进行注释，并参考美国医学遗传学和基因组学学会（ACMG）对所有变异位点进行致病等级评估。对候选位点进行Sanger验证，并对致病性证据不足的错义变异行Minigene体外功能验证。结果:先证者，男，7个月。视物追随反应差，指压眼征、畏光、眼球震颤，黄斑中心凹周围区视网膜色素上皮部分脱失。2岁时，F-ERG检查发现，双眼a、b波振幅重度降低，峰时延长，甚至无波形。先证者父母临床表型未见明显异常。WES结果显示，先证者 CEP290基因第40、2号外显子分别存在c.5515_5518del （p.Glu1839Lysfs*11）（V1）移码变异和c.74C>T （p.Ala25Val）（V2）错义变异。mtDNA测序结果为阴性。Sanger验证结果表明，先证者父亲、母亲分别携带杂合移码变异V1、新发错义变异V2，构成复合杂合变异。Minigene体外功能验证结果表明，V2变异使2号外显子产生一个新的剪接供体位点，从而导致2号外显子右侧缺失30个碱基对，蛋白质框内缺失10个氨基酸残基。ACMG评级分别为致病（V1）、可能致病变异（V2）。 结论:CEP290基因c.5515_5518del和新发变异c.74C>T构成复合杂合变异可能是本家系的致病原因，分别导致截短蛋白的产生和前体信使RNA的异常剪接。LCA具有发病年龄小、视功能严重损害和致病变异多样性等特点。

abstractsObjective:To identify and observe disease-causing gene variants and clinical phenotypes in a Han Chinese family with Leber congenital amaurosis (LCA).Methods:A retrospective study. A patient with LCA10 and his parents who had presented at Department of Ophthalmology of Henan Provincial People's Hospital on May 2022 were selected as the study subject. Detailed medical and family histories were recorded, fundus photography and flash electroretinogram (F-ERG) were performed. Peripheral venous blood samples (3 ml) of the proband and his parents were collected to extract whole genomic DNA, then whole exome sequencing (WES) and mitochondrial DNA (mtDNA) sequencing were carried out for the proband to determine the disease-causing gene and variants. All variants were annotated by bioinformatics analysis. According to the American College of Medical Genetics and Genomics (ACMG) guidelines, the pathogenicity of all detected variants were evaluated. Candidate variants were verified by Sanger sequencing, and in vitro minigene assay were performed to evaluate the impact of the missense variant with insufficient evidence on mRNA splicing.Results:The proband, male, 7-month-old, presented with an inability to follow light or objects, eye poking, photophobia, nystagmus, partial loss of retinal pigment epithelium around the fovea of the macula. At the age of 2 years old, F-ERG revealed severe reduction, elongation, or even no waveform of a-wave and b-wave in both eyes. No obvious abnormality was found in the clinical phenotype of his parents. The result of WES revealed that the proband carried two variants in exon 40 and exon 2 of CEP290, a frameshift variant c.5515_5518del (p.Glu1839Lysfs*11) (V1) and a novel missense variant c.74C>T (p.Ala25Val) (V2), respectively. The result of mitochondrial DNA sequencing was negative. Sanger sequencing confirmed that the heterozygous frameshift variant was inherited from his father and the heterozygous novel missense variant was inherited from his mother, which constituted compound heterozygous variants. In vitro minigene splicing assay confirmed that V2 created a new splicing donor at exon 2, leading to the in-frame deletion of 30bp fragment during transcription and loss of 10 amino acid residues in the protein. The two variants were pathogenic (V1) and likely pathogenic (V2) based on ACMG guidelines, respectively. Conclusions:The c.5515_5518del and novel c.74C>T compound heterozygous variants of the CEP290 gene probably are the cause of LCA10 in this family, which lead to the production of a truncated protein and aberrant splicing of pre-mRNA, respectively. LCA is characterized by early onset, severe impairment of visual function, and a wide range of disease-causing variations.