A deep intronic pathogenic variant was also discovered for a family with autosomal recessive polycystic kidney disease where one pathogenic variant in the PKHD1 gene was found already [28]; or for families with severe multisystemic optic atrophy syndromes where the one pathogenic variant in the OPA1 gene found already did not explain the severe multisystemic disease course [14,29]. The gene discussed is PKHD1; the disease is autosomal recessive polycystic kidney disease.