Genetic marker may help predict success of kidney transplant

Kidneys donated by people born with a small variation in the code of a key gene may be more likely, once in the transplant recipient, to accumulate scar tissue that contributes to kidney failure, according to a study led by researchers at the Icahn School of Medicine at Mount Sinai and published recently in theJournal of Clinical Investigation.

If further studies prove the variation to cause fibrosis (scarring) in the kidneys of transplant recipients, researchers may be able to use it to better screen potential donors and improve transplant outcomes. Furthermore, uncovering the protein pathways that trigger kidney fibrosis may help researchers design drugs that prevent this disease process in kidney transplant recipients, and perhaps in all patients with chronic kidney disease.

A commonly used study type in years, the genome-wide association study (GWAS) looks at differences at many points in the genetic code to see if, across a population, any given variation in the genetic code is found more often in those with a given trait; in the case of the current study, with increased fibrosis in recipients of donated kidneys.

Even the smallest genetic variations, called single nucleotide polymorphisms (SNPs), can have a major impact on a trait by swapping just one of 3.2 billion “letters” making up the human DNA code. The current study found a statistically significant association between an SNP identified as rs17319721 in the gene SHROOM3 and progressive kidney scarring (fibrosis) and function loss in a group of kidney donors, mostly of European descent. In many cases, certain SNPs will be more common in families or ethnic groups.

Researchers and clinicians have made great gains in preventing transplant rejection during the first few years by selectively suppressing the immune system, but long-term damage and disease remain a major challenge. The eventual development of an assay to predict whether a donor's kidney, once transplanted, would be more susceptible to inflammation or scarring may help overcome this challenge. Read the article.