Genotype and phenotype analysis and transplantation strategy in children with kidney failure caused by NPHP.

BACKGROUND

Nephronophthisis-related ciliopathies (NPHP-RC) have strong genotype and phenotype heterogeneity, and the transplantation strategy of Boichis syndrome is still controversial. Our purpose was to examine associations of genotype and phenotype in children with NPHP-RC and analyze the transplantation strategies of different phenotypes.

METHODS

The records of children with NPHP treated at our center from 01/2018 to 03/2021 were retrospectively reviewed. Inclusion criteria were a diagnosis of NPHP, received kidney transplantation, and received whole exome sequencing (WES) or nephropathy gene panel testing.

RESULTS

Twenty-nine children with NPHP were included. Nine children (31%) had NPHP1 mutations, and all presented with isolated nephropathy. Eighteen of 20 patients with non-NPHP1 mutations had compound heterozygous mutations, and 70% had extrarenal phenotype. Age at disease presentation (11.2 ± 1.94 years) and the development of kidney failure (12.4 ± 2.70 years) were later in children with NPHP1 mutations than those with non-NPHP1 mutations (5.2 ± 2.83 years and 5.7 ± 2.92 years, respectively). Four of six children with NPHP3 mutations were diagnosed with Boichis syndrome due to liver fibrosis. Isolated kidney transplantation resulted in good outcomes for patients with mild or moderate liver fibrosis without portal hypertension, while cholestasis was common postoperatively and could be resolved with ursodeoxycholic acid.

CONCLUSIONS

NPHP1 mutations are the most common in children with NPHP, and the phenotype of NPHP1 mutation is significantly different from that of non-NPHP1 mutation. For NPHP patients with mild to moderate liver fibrosis without portal hypertension, timely treatment of cholestasis could prevent the rapid progression of liver function damage after isolated kidney transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.