HTRA1 and age-related macular degeneration: The most common genetic contributors to AMD are variants associated with a cluster of genes near complement factor H (CFH) – complement factor H-related (CFHR) 5 on chromosome 1q32 (Chr1 locus) [22–27], and with age-related maculopathy susceptibility 2 (ARMS2) and high-temperature requirement factor A1 (HTRA1), two tightly-linked genes located on chromosome 10q26 (Chr10 locus) [28, 29].