ABCA4 and severe early-childhood-onset retinal dystrophy: The locus for recessive STGD was mapped to chromosome 1 (1p21–p13).3 Mutations in ABCA4 have been described in autosomal recessive STGD (arSTGD),4 autosomal recessive retinitis pigmentosa (arRP),5 autosomal recessive cone–rod dystrophy (arCRD)6 and age-related macular degeneration (AMD).7