Genetic architecture of routinely acquired blood tests in a British South Asian cohort.

Understanding the genetic basis of routinely-acquired blood tests can provide insights into several aspects of human physiology. We report a genome-wide association study of 42 quantitative blood test traits defined using Electronic Healthcare Records (EHRs) of ~50,000 British Bangladeshi and British Pakistani adults. We demonstrate a causal variant within the PIEZO1 locus which was associated with alterations in red cell traits and glycated haemoglobin. Conditional analysis and within-ancestry fine mapping confirmed that this signal is driven by a missense variant - chr16-88716656-G-T_T - which is common in South Asian ancestries (MAF 3.9%) but ultra-rare in other ancestries. Carriers of the T allele had lower mean HbA1c values, lower HbA1c values for a given level of random or fasting glucose, and delayed diagnosis of Type 2 Diabetes Mellitus. Our results shed light on the genetic basis of clinically-relevant traits in an under-represented population, and emphasise the importance of ancestral diversity in genetic studies.Here, the authors used electronic healthcare records to analyse the genetic basis of variation in 42 routinely-acquired quantitative blood tests among up to 40,000 British South Asian volunteers from the Genes and Health study. By combining their results with genetic findings from UK Biobank, they explore similarities and differences between ancestries in the genetic basis of these traits. [ABSTRACT FROM AUTHOR]