Diagnostic algorithm for suspected cases of NPHP. ARPKD: autosomal recessive polycystic kidney disease; BBS: Bardet-Biedl syndrome; CKD: chronic kidney disease; Coag: coagulation; ERF: established renal failure; FBC: full blood count; JS: Joubert syndrome; LFT: liver function tests; Mg: magnesium; MRI: magnetic resonance imaging; NPHP: nephronophthisis; RRT: renal replacement therapy; UE: urea and electrolytes.