STRs database » AFF3 locus

Overview of repeats

Metsu et al. (2014) identified CGG expansions at FRA2A in three families with neurodevelopmental phenotypes. Control alleles contained 3-20 repeats, while unaffected transmitting mothers carried 106 or approximately 120 and affected offspring carried more than 300 repeat units and were associated with promoter hypermethylation and monoallelic AFF3 expression. In an independent study, Jadhav et al. (2024) found enrichment of methylated AFF3 expansions among 6371 probands with neurodevelopmental problems and reported associations with educational attainment in a population cohort. In the 2024 study, 99% of control alleles were at most 38 copies, and enrichment was strongest at short-read estimates of at least 61 copies.