BBS2 and cystic kidney disease: The molecular genetic diagnosis confirmed the pre-ES clinical diagnosis, with detection of pathogenic variants in cystic kidney disease or nephronophthisis genes, including PKD1 (25), PKD2 (3), PKHD1 (25), NPHP3 (1), WDR19 (1), RPGRIP1L (1), BBS1 (1), BBS2 (1), and SDCCAG8 (1).