NPHP4 and inherited retinal dystrophy: Biallelic loss of function or missense variants in NPHP1, NPHP4, and NPHP5/IQCB1 are among the main causes of juvenile or late onset NPH, which can be isolated (NPHP1, NPHP4) or associated with retinal dystrophies in Senior-Løken syndrome (NPHP1, NPHP4, NPHP5; OMIM: #266900).3