NOTCH3 p.Arg1231Cys is markedly enriched in South Asians and associated with stroke

Acknowledgements: Supported by Regeneron Pharmaceuticals, Inc. This research has been conducted using the UK Biobank Resource (project 26041). The authors thank everyone who made this work possible, particularly the UK Biobank team, their funders, the professionals from the member institutions who contributed to and supported this work, and most especially the UK Biobank participants, without whom this research would not be possible. The exome sequencing was funded by the UK Biobank Exome Sequencing Consortium (Bristol Myers Squibb, Regeneron, Biogen, Takeda, Abbvie, Alnylam, AstraZeneca and Pfizer). Ethical approval for the UK Biobank was previously obtained from the North West Center for Research Ethics Committee (11/NW/0382). Disclosure forms provided by the authors are available with the full text of this article.The genetic factors of stroke in South Asians are largely unexplored. Exome-wide sequencing and association analysis (ExWAS) in 75 K Pakistanis identified NM_000435.3(NOTCH3):c.3691 C > T, encoding the missense amino acid substitution p.Arg1231Cys, enriched in South Asians (alternate allele frequency = 0.58% compared to 0.019% in Western Europeans), and associated with subcortical hemorrhagic stroke [odds ratio (OR) = 3.39, 95% confidence interval (CI) = [2.26, 5.10], p = 3.87 × 10−9), and all strokes (OR [CI] = 2.30 [1.77, 3.01], p = 7.79 × 10−10). NOTCH3 p.Arg231Cys was strongly associated with white matter hyperintensity on MRI in United Kingdom Biobank (UKB) participants (effect [95% CI] in SD units = 1.1 [0.61, 1.5], p = 3.0 × 10−6). The variant is attributable for approximately 2.0% of hemorrhagic strokes and 1.1% of all strokes in South Asians. These findings highlight the value of diversity in genetic studies and have major implications for genomic medicine and therapeutic development in South Asian populations