PRRX1 and learning disability: Interestingly, a small number of individuals have been described with heterozygous deletions of 1q24.2 linked to syndromic learning disability, with short stature, brachydactyly, and facial dysmorphism as additional features.31, 32, 33 Although PRRX1 falls outside of the shortest region of overlap for the full syndrome, a pair of monozygotic twins has been described with an approximately 2.6 Mb deletion including PRRX1, both of whom required surgery for craniosynostosis.32