A Genome-Wide Association Study Identifies Variants in Casein Kinase II (CSNK2A2) to be Associated with Leukocyte Telomere Length in a Punjabi Sikh Diabetic Cohort
Background—Telomere length is a heritable trait and short telomere length has been associated with multiple chronic diseases. We investigated the relationship of relative leukocyte telomere length (RTL) with cardiometabolic risk and performed the first GWAS and meta-analysis to identify variants influencing RTL in a population of Sikhs from South Asia.
Methods and Results—Our results revealed a significant independent association of shorter RTL with type 2 diabetes (T2D) and heart disease. Our discovery GWAS (n=1,616) was followed by Stage 1 replication of 25 top signals (P<10-6) in an additional Sikhs (n=2,397). On combined discovery and Stage 1 meta-analysis (n= 4013), we identified a novel RTL locus at chromosome 16q21 represented by an intronic variant (rs74019828) in the CSNK2A2 gene (β -0.38, P=4.5x10-8). We further tested 3 top variants by genotyping in UKCVD (Caucasians n=2,952) for Stage 2. Next we performed in silico replication of 139 top signals (p<10-5) in UKTWIN, NHS, PLCO and MDACC (n=10,033) and joint meta-analysis (n=16,998). The observed signal in CSNK2A2 was confined to South Asians and could not be replicated in Caucasians due to significant difference in allele frequencies (P<0.001). CSNK2A2 phosphorylates TRF1 and plays an important role for regulation of telomere length homoeostasis.
Conclusions—By identification of a novel signal in telomere pathway genes, our study provides new molecular insight into the underlying mechanism that may regulate telomere length and its association with human aging and cardiometabolic pathophysiology.
- Received September 3, 2013.
- Revision received March 25, 2014.
- Accepted April 1, 2014.