NPHP1 and Senior-Loken syndrome: We have also identified several instances of a recurrent duplication and a recurrent deletion of the complete coding region of NPHP1 (NM_000272.3), which are expected to have arisen through non-allelic homologous recombination between segmental duplications flanking NPHP1. 35 The deletion of NPHP1 has been frequently reported as a cause of autosomal recessive juvenile nephronophthisis and Senior-Loken syndrome.