NMNAT1 and Leber congenital amaurosis: Two unrelated cases (3701 and 3801) of LCA due to mutations in GUCY2D (MIM *600179) and NMNAT1 (MIM *608700), were both diagnosed with unilateral (right eye) visually significant cataract of at the age of 6, whilst the contralateral eye showed mild cataract of no visual significance.