Exome-wide association study on Albuminuria identifies a novel rare variant in CUBN and additional genes, in 33,985 Europeans with and without diabetes

Identifying rare coding variants associated with albuminuria may open new avenues for preventing chronic kidney disease (CKD) and end-stage renal disease which are highly prevalent in patients with diabetes. Efforts to identify genetic susceptibility variants for albuminuria have so far been limited with the majority of studies focusing on common variants. We performed an exome-wide association study to identify coding variants in a two phase (discovery and replication) approach, totalling to 33,985 individuals of European ancestry (15,872 with and 18,113 without diabetes) and further testing in Greenlanders (n = 2,605). We identify a rare (MAF: 0.8%) missense (A1690V) variant in CUBN (rs141640975, β =0.27, p =1.3 × 10 −11 ) associated with albuminuria as a continuous measure in the combined European meta-analyses. Presence of each rare allele of the variant was associated with a 6.4% increase in albuminuria. The rare CUBN variant had 3 times stronger effect in individuals with diabetes compared to those without ( p interaction : 5.4 × 10 −4 , β DM : 0.69, β non-DM : 0.20) in the discovery meta-analyses. Gene aggregate tests based on rare and common variants identify three additional genes associated with albuminuria ( HES1 , CDC73 , and GRM5 ) after multiple testing correction ( p_bonferroni −6 ). The current study identifies a rare coding variant in the CUBN locus and other potential genes associated with albuminuria in individuals with and without diabetes. These genes have been implicated in renal and cardiovascular dysfunction. These findings provide new insights into the genetic architecture of albuminuria and highlight novel target genes and pathways for prevention of diabetes-related kidney disease.