# Variant level heritability estimates of type 2 diabetes in African Americans

## TL;DR

This study estimates the genetic contribution to type 2 diabetes in African Americans using genetic data from over 19,000 individuals.

## Contribution

The study provides novel heritability estimates of type 2 diabetes in African Americans using two genome-wide methods.

## Key findings

- Heritability estimates for type 2 diabetes in African Americans ranged from 18% to 34%.
- Adjusting for age, sex, and genetic ancestry narrowed the expected heritability range compared to prior estimates.

## Abstract

Type 2 diabetes (T2D) is caused by both genetic and environmental factors and is associated with an increased risk of cardiorenal complications and mortality. Though disproportionately affected by the condition, African Americans (AA) are largely underrepresented in genetic studies of T2D, and few estimates of heritability have been calculated in this race group. Using genome-wide association study (GWAS) data paired with phenotypic data from ~ 19,300 AA participants of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, Genetics of Hypertension Associated Treatments (GenHAT) study, and the Electronic Medical Records and Genomics (eMERGE) network, we estimated narrow-sense heritability using two methods: Linkage-Disequilibrium Adjusted Kinships (LDAK) and Genome-Wide Complex Trait Analysis (GCTA). Study-level heritability estimates adjusting for age, sex, and genetic ancestry ranged from 18% to 34% across both methods. Overall, the current study narrows the expected range for T2D heritability in this race group compared to prior estimates, while providing new insight into the genetic basis of T2D in AAs for ongoing genetic discovery efforts.