Ultrasonographic manifestation and genetic analysis of a fetus with nephronophthisis type 2

OBJECTIVE: To carry out genetic analysis for a family with a fetus manifesting bilateral polycystic renal dysplasia and oligohydramnios at 16(+) gestational week and a previous history for fetal renal anomaly. METHODS: Ultrasound scan was carried out to detect the morphological changes. Following genetic counselling, the parents had decided to terminate the pregnancy. Fetal kidneys were subjected to histological examination. Target capture and next generation sequencing (NGS) was applied to the abortus to detect potential variants. The results were verified by Sanger sequencing. RESULTS: Histological examination of fetal kidneys revealed cystic changes without cortex, medulla or normal renal structure. NGS has identified a heterozygous c.100+1G>A variant and deletion of exon 3 of the INVS gene, which were respectively inherited from the mother and father. CONCLUSION: Through NGS and Sanger sequencing, the fetus was diagnosed with type II nephronophthisis (NPHP2). Above result can provide guidance for further pregnancy and enforce understanding of clinical features and genetic etiologies for NPHP.