Prenatal diagnosis and prognosis of fetal hyperechogenic kidney: a study of 65 cases

Abstract

Objective To investigate prenatal diagnosis and prognosis of fetus with hyperechogenic kidney. Methods Clinical data of 65 cases prenatally diagnosed with fetal hyperechogenic kidney in Peking University First Hospital between July, 2009 and May, 2015 were retrospectively analyzed. Results of fetal ultrasound screening and pregnancy outcomes were analyzed and Growth and development status of those babies were followed up until December, 2015. Independent-sample-t, Chi-square or Fisher's exact test was applied for statistical analysis. Results Among the 65 cases, including 48(73.8%) bilateral and 17 (26.2%) unilateral, 34 cases (52.3%) were diagnosed as non-isolated and 31 cases (47.7%) as isolated fetal hyperechogenic kidney. The primary associated malformations with non-isolated fetal hyperechogenic kidney included cardiac abnormality (14 cases, 41.2%), urinary system abnormality (12 cases, 35.2%) , skeletal system abnormality (nine cases, 26.5%), central nervous system abnormality (eight cases, 23.5%) and Meckel-Gruber sydrome (one case, 2.9%). Amniotic volume, the size and numbers of affected kidney between non-isolated and isolated groups showed no significant differences (all P>0.05) . Twenty out of the 65 cases (30.8%) received fetal karyotyping and one received non-invasive prenatal testing, and no abnormality was detected. Three cases received cord blood array comparative genomic hybridization with negative results. Pathogenic genes were found in two cases who received targeted exome capture with high throughput sequencing, including a TTC21B mutation in cord blood in one case and a HNF1β deletion mutation in peripheral blood after birth in the other. There were 23 (35.4%) terminations of pregnancy and 42 (64.6%) live births among which three died after birth. The rate of live birth was significantly higher in the isolated group than in the non-isolated group[87.1%(27/31) vs 44.1%(15/34), χ2=13.101, P<0.01]. Of the fifteen live births in the non-isolated group, there were fourteen survived symptom-free except that one lost to follow-up. Of the 27 live births in the isolated group, follow-up study revealed 23 symptom-free survivors, one lost, two neonatal deaths (one died of volvulus neonatorum, and the other due to unknown causes) and one death of renal and liver function failures at the age of two-and-a-half. Conclusions Fetal hyperechogenic kidney is an important prenatal ultrasound marker for congenital renal anomalies, and the prognosis of non-isolated fetal hyperechogenic kidney is poor. The current rate of abnormal karyotype in fetus with hyperechogenic kidney is very low. However, the rate of prenatal genes screening should be encouraged. Key words: Ultrasonography, prenatal; Fetal diseases; Kidney diseases, cystic; Prognosis