Prenatal detection of isolated bilateral hyperechogenic kidneys: Etiologies and outcomes. (20th February 2019) - Shuster, Shirley
Abstract: Objectives: To delineate the etiology and outcome of prenatally diagnosed isolated bilateral hyperechogenic kidneys (IBHK). Study Design: Pregnancies with IBHK on prenatal ultrasound identified and followed by us between January 1, 2000 and January 1, 2015 were evaluated regarding the etiology and outcome by evaluation of family history, targeted AR‐PKD and AD‐PKD DNA analysis, and microarray analysis, according to renal size and amniotic fluid volume. Results: Of the 52 identified cases, there were 34 cases with enlarged kidneys, 16 with normal size kidneys, and two with small kidneys. There were seven cases with AD‐PKD, six inherited, and one with de novo causative variants in the PKD1 gene. Fifteen had AR‐PKD, and microarray analysis showed two inherited findings: one with 17q12 deletion including the HNF1B/TCF2 gene inherited from asymptomatic mother and a duplication at 3p26.1 inherited from a healthy father. Of the remaining four cases, three cases had bilateral multicystic dysplastic kidneys, and one had unilateral renal agenesis. Conclusion: Microarray analysis and mutation analysis for PKD1 and PKHD1 have an important contribution to the diagnostic investigation of IBHK and to the management of affected and future pregnancies. Poor outcome was associated with large hyperechoic kidneys with oligohydramnios. Abstract : What's already known about this topic: Isolated bilateral fetal hyperechogenic kidneys is etiologically a heterogeneous condition. Both inherited and non‐inherited etiologies have been identified. The worst prognosis is associated with enlarged kidneys and oligohydramnios Cases with fetal hyperechogenic kidneys with large kidneys and normal amniotic fluid but poor prognosis have also been reported. What does this study add? Molecular analysis for PKD1, PKD2, and PKHD1 can help in identifying the diagnosis and thus refining the prognosis. Chromosomal microarray analysis has a low yield in the investigation of cases with isolated bilateral fetal hyperechogenic kidneys but is useful in detection of deletions such as deletion of the HNF1B/TCF2 gene associated with this condition. All affected parents with AD‐PKD and affected pregnancies decided not to have prenatal diagnosis and to continue the pregnancy. Many cases with isolated bilateral fetal hyperechogenic kidneys remain of unknown etiology despite targeted analysis of PKD1, PKD2, and PKHD1, and chromosomal microarray analysis, and require further diagnostic evaluation using panels for congenital abnormalities of the kidneys and urinary tract (CAKUT) and/or WES/WGS.