Clinical phenotype characteristics and genetic analysis in children with nephronophthisis and related syndromes caused by different gene mutations

Abstract:

Objective To improve the understanding of the clinical phenotypes and genetic characteristics of nephronophthisis (NPHP) and related syndromes in children.Methods A retrospective analysis was performed on the medical data of eight children with NPHP and related syndromes who were diagnosed and treated in the Department of Pediatrics of the Second Hospital of Hebei Medical University, from January 2018 to November 2022. The clinical characteristics and genetic testing results were analyzed.Results Among these eight children, there were five boys and three girls, with an age of onset ranging from 15 months to 12 years. All 8 children exhibited different degrees of renal function abnormalities when they attended the hospital. Among the eight children, two had the initial symptom of delayed development, two had the initial symptom of anemia, and two were found to have abnormal renal function during physical examination. The extrarenal manifestations included cardiovascular abnormalities in two children, skeletal dysplasia in two children, liver dysfunction in one child, retinitis pigmentosa in one child, and visceral translocation in one child. All eight children had renal structural changes on ultrasound, and four children had mild to moderate proteinuria based on routine urine test. Of all eight children, five had NPHP1 gene mutations and one each had a gene mutation in the NPHP3, IFT140, and TTC21B genes, and four new mutation sites were discovered.Conclusions Children with NPHP and related syndromes often have the initial symptom of delayed development or anemia, and some children also have extrarenal manifestations. NPHP and related syndromes should be considered for children with unexplained renal dysfunction, and high-throughput sequencing may help to make a confirmed diagnosis.