Group 5 (congenital cataracts) also shows abundant proteins involved in protein metabolism, among which three proteins—corticosteroid-binding globulin-SERPINA6, apolipoprotein A-IV (APOA4), and inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4)—were downregulated compared to other groups. Here, ITIH4 is linked to early-onset non-syndromic cataract.