Recent genome-wide analysis identified a genetic variant on 5p14.1 (rs4307059), which is associated with risk for autism spectrum disorder (ASD). We recently investigated up to 7313 ALSPAC children and studied association between rs4307059 and potential broader autism traits including early vocabulary and communication (MacArthur-Communicative-Development-Inventory/MacArthur-Toddler-Communication-Questionnaire; Denver-Developmental-Screening-Test), social behaviour and behavioural difficulties (Emotionality-Activity-Sociability-Temperament-Survey; Revised-Rutter-Parent-Scale for Preschool Children; Standard-Assessment-Tests of social skills; Strengths-and-Difficulties-Questionnaire, Cambridge Hormones-and-Moods-Project-Friendship-Questionnaire; Special-Educational-Needs assessment), social communication (Social-and-Communications-Disorders-Checklist; Children's-Communication-Checklist) and verbal intelligence (Wechsler-Intelligence-Scale-for-Children-III) assessed between 15-months and 12-years. Our results suggested that common variation in rs4307059 is associated with ASD-related phenotypes and support the role of rs4307059 as QTL for ASD. We aim to extend this approach and investigate the association between the SNP and ASD-related traits assessed in mothers. We therefore propose to genotype rs4307059 in the ALSPAC maternal sample.