AHI1 and nephronophthisis: Heterozygous AHI1 variants are enriched in patients with homozygous NPHP1 and neurological symptoms [41];More severe neurological disease in a patient with bi-allelic CEP290 variants and a heterozygous AHI1 [47];Heterozygous AHI1 variants are associated with retinal disease irrespective of the underlying bi-allelic cause of nephronophthisis [74].