C1QC and neurodegenerative disease: Therefore, C1qa, C1qb, and C1qc may also be involved in the pathogenesis of congenital cataracts caused by Crim1 mutation, and these proteins may also be related to neurodegenerative diseases (Fig. 8b).However, the complement C1q protein domain was significantly downregulated in the lens of Tdrd7 cataractous mutant mice, which we hypothesized might be related to mutations in different genes.