Mutations in several chromosomal loci have been implicated in ARS including PITX2 (paired-like homeodomain transcription factor 2; 4q25; OMIM 601542), FOXC1 (forkhead box C1; 6p25; OMIM 601090), PAX6 (paired box gene 6; 11p13; OMIM 607108) and MAF (v-MAF avian musculoaponeurotic fibrosarcoma oncogene homolog; 16q24; OMIM 177075). Here, PITX2 is linked to Axenfeld-Rieger syndrome.