rs4783244 — CDH13

CDH13 — The Adiponectin Receptor Efficiency Gene

T-cadherin (also called H-cadherin) is encoded by the CDH13 gene and is one of the body's most abundant adipokine receptors. Unlike other cadherin proteins, T-cadherin lacks the intracellular signalling domain and is anchored to the cell surface by a GPI anchor¹¹ GPI anchor
Glycosylphosphatidylinositol: a lipid anchor that tethers proteins to the outer leaflet of the plasma membrane, common in signalling receptors on vascular cells. On vascular endothelial cells and smooth muscle, T-cadherin acts as the primary binding receptor for high-molecular weight (HMW) adiponectin — the cardioprotective form of the most abundant circulating adipokine. The rs4783244 variant in intron 1 of CDH13 is among the strongest GWAS signals ever identified for circulating adiponectin levels, yet its health consequences are the opposite of what you might expect from the adiponectin number alone.

The Mechanism

rs4783244 sits in the first intron of CDH13 and influences the gene's transcriptional activity. The 2021 functional haplotype study by Er et al.²² 2021 functional haplotype study by Er et al.
Er et al. Genome-Wide Association Study on Adiponectin-Mediated Suppression of HDL-C Levels in Taiwanese Individuals Identifies Functional Haplotypes in CDH13. Genes, 2021 showed that the GG haplotype (tagged by the G allele at rs4783244) increased CDH13 enhancer activity by approximately 80%, while the TT haplotype reduced it by about 28%. This means the G allele drives higher CDH13/T-cadherin expression on vascular cells.

The paradox emerges here: higher T-cadherin expression means more binding capacity for HMW adiponectin — which sequesters it at the cell surface and lowers the concentration of freely circulating adiponectin. The G allele therefore produces higher circulating adiponectin as a compensatory response³³ higher circulating adiponectin as a compensatory response
Elevated adiponectin in G-allele carriers reflects an adiponectin-resistant state where more adiponectin is produced to overcome reduced signalling efficiency at the receptor level, similar to how elevated insulin can indicate insulin resistance rather than metabolic health. The T allele reduces CDH13 expression, resulting in lower circulating adiponectin but more efficient transduction of each adiponectin molecule that does bind.

The Evidence

The CDH13 locus was first identified as a top GWAS hit for adiponectin in a 2011 Taiwanese cohort study⁴⁴ 2011 Taiwanese cohort study
Chung et al. A genome-wide association study reveals a quantitative trait locus of adiponectin on CDH13 that predicts cardiometabolic outcomes. Diabetes, 2011. The rs4783244 SNP in intron 1 was the lead signal (p=7.57×10⁻⁹). Crucially, T allele carriers in that study had lower adiponectin but better cardiometabolic outcomes: metabolic syndrome OR=1.42 per G allele, T2D OR=3.25 for men with GG, and ischemic stroke OR=2.13 per G allele.

The largest effect-size estimate comes from a 2013 meta-analysis of 7,334 East Asians by Gao et al.⁵⁵ 2013 meta-analysis of 7,334 East Asians by Gao et al.
Gao et al. Genetic variation in CDH13 is associated with lower plasma adiponectin levels but greater adiponectin sensitivity in East Asian populations. Diabetes, 2013. Each T allele reduced total adiponectin by β=−0.34 (p=2×10⁻⁷⁰) and HMW adiponectin by β=−0.40 (p=1×10⁻¹¹⁷), explaining 6.5% of HMW adiponectin variance. But after adjusting for adiponectin levels, the T allele was associated with lower BMI (β=−0.15), reduced insulin resistance (β=−0.16), lower triglycerides (β=−0.16), and higher HDL cholesterol (β=0.16) — a uniformly better metabolic profile.

Long-term outcome data from the J-SHIPP study (Uetani et al. 2014)⁶⁶ J-SHIPP study (Uetani et al. 2014)
Uetani et al. CDH13 genotype-dependent association of high-molecular weight adiponectin with all-cause mortality: the J-SHIPP study. Diabetes Care, 2014 followed 2,020 Japanese subjects for a mean of 6.5 years. All-cause mortality risk increased linearly with the number of G alleles (p=0.023 for genotype interaction), and the HMW adiponectin-to-mortality relationship showed a hazard ratio of 1.92 (p=0.006) — a finding consistent with elevated adiponectin being a marker of metabolic stress rather than protection in this gene context.

A Japanese study of 945 subjects by Kitamoto et al. 2016⁷⁷ Japanese study of 945 subjects by Kitamoto et al. 2016
Kitamoto et al. CDH13 Polymorphisms are Associated with Adiponectin Levels and Metabolic Syndrome Traits Independently of Visceral Fat Mass. J Atheroscler Thromb, 2016 confirmed that the G allele association with higher adiponectin persisted even after adjusting for visceral fat — ruling out obesity as a confounder and supporting the intrinsic adiponectin-resistance model.

Practical Actions

For carriers of one or two copies of the G allele (GG or GT), the key insight is that a standard serum adiponectin measurement may appear reassuring (adiponectin looks high) while masking a functionally impaired adiponectin-signalling state. Conventional adiponectin thresholds for cardiovascular risk stratification were developed without CDH13 genotyping. In G allele carriers, it is more informative to track direct metabolic biomarkers — fasting insulin, HOMA-IR, triglycerides, and HDL — than to rely on adiponectin levels as a proxy for cardiometabolic health.

For TT homozygotes, lower circulating adiponectin is expected and does not indicate a problem; the signal-per-molecule is more efficient. Standard metabolic biomarkers apply without the CDH13-specific caveat.

Interactions

The CDH13 locus contains several variants in partial LD with rs4783244. rs12051272 (also intron 1) showed the strongest single-SNP association in the Japanese population (p=9.5×10⁻²⁰ for HMW adiponectin in Morisaki et al. 2012). rs3865188 and rs12922394 are in the same haplotype block and were examined in the Kitamoto 2016 and COPD studies. These four variants together define the CDH13 risk haplotype; a user carrying the G allele at rs4783244 likely carries the risk-tagged alleles at the others.

There is a documented interaction between CDH13 rs7193788 and type 2 diabetes: in the Chen et al. 2017 Chinese stroke study, diabetic GA/AA carriers at rs7193788 faced OR=2.64 for ischemic stroke — suggesting CDH13-mediated adiponectin signalling interacts with glycaemic status to modulate vascular risk.