Speech and language development in children with 49,XXXXY syndrome

49,XXXXY is the rarest X and Y chromosomal variation and is frequently characterized by expressive and receptive language dysfunction, low muscle tonus, and intellectual deficits. Due to the low incidence of this disorder, comprehensive studies analyzing the specific aspects of the speech and language phenotype in these boys have been uncommon. This is the first in-depth investigation of the speech and language profiles in a large cohort of boys...