Dyslexia-related loci are significantly associated with language and literacy in Chinese–English bilingual Hong Kong Chinese twins

A recent genome-wide association study on dyslexia in 51,800 affected European adults and 1,087,070 controls detected 42 genome-wide significant single nucleotide variants (SNPs). The association between rs2624839 in SEMA3F and reading fluency was replicated in a Chinese cohort. This study explores the genetic overlap between Chinese and English word reading, vocabulary knowledge and spelling, and aims at replicating the association in a unique cohort of bilingual (Chinese–English) Hong Kong Chinese twins. Our result showed an almost complete genetic overlap in vocabulary knowledge ( r 2 = 0.995), and some genetic overlaps in word reading and spelling ( r 2 = 0.846, 0.687) across the languages. To investigate the region near rs2624839, we tested proxy SNPs (rs1005678, rs12632110 and rs12494414) at the population level ( n = 305–308) and the within-twin level ( n = 342–344 [171–172 twin pairs]). All the three SNPs showed significant associations with quantitative Chinese and English vocabulary knowledge ( p