Klotho variants and chronic hemodialysis mortality

Area of Science:

• Genetics
• Nephrology
• Molecular Biology

Background:

• End-stage renal disease (ESRD) patients on chronic hemodialysis face high first-year mortality.
• Vitamin D and fibroblast growth factor (FGF)-23 levels impact survival in ESRD.
• Klotho, a key protein in the vitamin D/FGF-23 pathway, is implicated in aging and mortality.

Purpose of the Study:

• To investigate the association between genetic variations in the Klotho gene and 1-year mortality in ESRD patients undergoing hemodialysis.

Main Methods:

• A cohort study of 1307 white and Asian ESRD patients was conducted.
• Twelve single nucleotide polymorphisms (SNPs) in the Klotho gene were analyzed for association with mortality.
• Klotho gene expression was assessed in lymphoblastoid cell lines.

Main Results:

• A significant association was found between the CC genotype of the Klotho SNP rs577912 and an increased risk of 1-year mortality (RR, 1.76).
• This mortality risk was more pronounced in patients not receiving activated vitamin D supplementation (HR, 2.51).
• The CC genotype correlated with 16-21% lower Klotho expression compared to AA/AC genotypes.

Conclusions:

• A specific Klotho gene variant (rs577912) is associated with survival in ESRD patients initiating hemodialysis.
• Activated vitamin D therapy may potentially modify the mortality risk associated with this Klotho variant.
• These findings highlight the role of Klotho genetics in ESRD patient outcomes.