目前先天性白内障(CC)的基因诊断工作主要基于NGS面板,而外显子组测序(ES)偶尔被采用。在这项多中心研究中,我们通过ES调查了检测产量,2020年至2022年中期招募的CC队列中的突变谱和基因型-表型相关性。该队列由来自51个无关家庭的67个受影响的个体组成,包括非综合征(75%)和综合征(25%)表型。两组都存在CC外眼部/视觉特征(48%和76%,分别)。通过3D建模和亲水特性变化来预测变体的功能效果。变异聚类用于基因型-表型相关性的深入评估。在51个先证者/家庭中的19个(〜37%)中鉴定出诊断(致病性或可能致病性)变异。在另外14个先证者/家庭中,确定了候选变体:在12个家庭中检测到VUS,其中9个被认为是合理致病的(即,根据ACMG标准4或5分),而在2个先证者中,ES鉴定出与CC相关的常染色体隐性基因中的单个变体。十八个先证者/家庭,主要表现为非综合征性CC(15/18,83%),仍未解决。确定的变体(8个P,12LP,10VUS-PP,和5VUS),其中一半在文献中没有报道,影响涉及转录/剪接的基因的五个功能类别,晶状体形成/体内平衡(即,晶状体蛋白基因),膜信号,细胞-细胞相互作用,和免疫反应。在四个基因(KIF1A,MAF,PAX6,SPTAN1),而可变的表现力和潜在的表型扩展在两个(BCOR,NHS)和五个基因(CWC27,KIF1A,IFIH1,PAX6,SPTAN1),分别。最后,ES允许检测商业CC面板中通常不包括的六个基因中的变体。这些发现扩大了ES测试的最大CC队列之一的基因型-表型相关性,提供对潜在致病机制的新见解,并强调ES作为第一层测试的力量。
The current genetic diagnostic workup of congenital cataract (CC) is mainly based on NGS panels, whereas exome sequencing (ES) has occasionally been employed. In this multicentre study, we investigated by ES the detection yield, mutational spectrum and genotype-phenotype correlations in a CC cohort recruited between 2020 and mid-2022. The cohort consisted of 67 affected individuals from 51 unrelated families and included both non-syndromic (75%) and syndromic (25%) phenotypes, with extra-CC ocular/visual features present in both groups (48% and 76%, respectively). The functional effect of variants was predicted by 3D modelling and hydropathy properties changes. Variant clustering was used for the in-depth assessment of genotype-phenotype correlations. A diagnostic (pathogenic or likely pathogenic) variant was identified in 19 out of 51 probands/families (~37%). In a further 14 probands/families a candidate variant was identified: in 12 families a VUS was detected, of which 9 were considered plausibly pathogenic (i.e., 4 or 5 points according to ACMG criteria), while in 2 probands ES identified a single variant in an autosomal recessive gene associated with CC. Eighteen probands/families, manifesting primarily non-syndromic CC (15/18, 83%), remained unsolved. The identified variants (8 P, 12 LP, 10 VUS-PP, and 5 VUS), half of which were unreported in the literature, affected five functional categories of genes involved in transcription/splicing, lens formation/homeostasis (i.e.,
crystallin genes), membrane signalling, cell-cell interaction, and immune response. A phenotype-specific variant clustering was observed in four genes (KIF1A, MAF, PAX6, SPTAN1), whereas variable expressivity and potential phenotypic expansion in two (BCOR, NHS) and five genes (CWC27, KIF1A, IFIH1, PAX6, SPTAN1), respectively. Finally, ES allowed to detect variants in six genes not commonly included in commercial CC panels. These findings broaden the genotype-phenotype correlations in one of the largest CC cohorts tested by ES, providing novel insights into the underlying pathogenetic mechanisms and emphasising the power of ES as first-tier test.