Whole-exome Sequencing Screening for Candidate Genes and Variants Associated with Primary Sporadic Keratoconus in Chinese Patients

The pathogenesis of keratoconus (KC) is complex, and genetic factors play an important role. The purpose of this study was to screen and analyse candidate genes and variants in Chinese patients with primary sporadic KC. Whole-exome sequencing (WES) was performed to identify candidate genes and variants in 105 unrelated Chinese patients with primary sporadic KC. Through a series of screening processes, 54 candidate variants in 26 KC candidate genes were identified in 53 KC patients (53/105, 50.5%). These 54 candidate variants included 10 previously identified variants in 9 KC candidate genes and 44 novel variants in 20 KC candidate genes. The previously identified variants occurred in 25.7% (27/105) of patients. Of these, 4 variants (COL6A5, c.5014T > G; CAST, c.1814G > A; ZNF469, c.946G > A; and MPDZ, c.3836A > G) were identified for the first time in Chinese KC patients. The novel variants occurred in 33.3% (35/105) of patients. Of the 26 screened KC candidate genes, 11 KC candidate genes (CAT, COL12A1, FLG, HKDC1, HSPG2, PLOD1, ITGA2, TFAP2B, USH2A, WNT10A, and COL6A5) were found to be potentially pathogenic in Chinese KC patients for the first time. Gene Ontology (GO) biological process (BP) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on the 26 KC candidate genes using the Database for Annotation, Visualization, and Integrated Discovery (DAVID). The results showed that the KC candidate genes were significantly enriched in biological processes such as collagen fibril organization and extracellular matrix (ECM) organization and in ECM-receptor interaction and protein digestion and absorption pathways. The results further expand the spectrum of KC candidate variants and provide a basis for further KC gene studies.