Researchers have identified a group of genes that could shed light on the underlying mechanism for childhood nephrotic syndrome -- a chronic kidney disease among children.

Childhood nephrotic syndrome, also called nephrotic, is an incurable disease with an unknown cause, characterised by large amounts of protein leaving the body in the patient's urine, and protein levels in the bloodstream becoming extremely low. The majority of patients develop steroid-sensitive nephrotic syndrome that responds to steroids and immune-suppressing drugs, and go into remission, but at least 20 per cent of cases are resistant strains that recur repeatedly during adulthood, the researchers said.

It is thought that people who are genetically predisposed develop the syndrome when exposed to an immunological stimulus such as infection, they added. "With this study there is a high possibility that we will be able to identify other susceptible genes," said co-author Kazumoto Iijima, Professor at the Kobe University Graduate School of Medicine in Japan.

For the study, published in the Journal of the American Society of Nephrology, the research team collected genetic DNA from 1,300 sufferers of childhood nephrotic syndrome. The study targeted 224 of the samples with childhood steroid-sensitive nephrotic syndrome and a control group of 419 healthy people to perform a genome-wide association study (GWAS).

This enabled them to identify SNPs with a significant genome-wide association in the HLA-DR/DQ area of the short arm of human chromosome six. They then identified the HLA haplotypes (gene groups) with the lowest and highest risks of developing the syndrome. The researchers confirmed this result with a different cohort of 213 samples of infant steroid-sensitive nephrotic syndrome and a control group of 710 healthy individuals.