Leber congenital amaurosis (LCArpar; is a heterogeneous disorder representing the congenital forms of retinitis pigmentosa accounting for about 5% of all retinal dystrophies. The RPE65 gene product is required for regeneration of the visual pigment for phototransduction. Defects in the RPE65 gene have so far been shown to account for approximately 10 % of known cases of LCA. Here we describe four additional novel mutations in the RPE65 gene (c.889delA, c.131G>A, c.1249G>C, c.430T>G) and several novel polymorphisms in a large series of LCA patients. Hum Mutat 18:164, 2001.