Autism spectrum disorder and Klinefelter syndrome

Background Autism is a severe handicapping disorder of early childhood characterized by a distinct pattern of social and communication impairment with rigid ritualistic interests. In about 10-25% of cases, it is associated with known medical conditions. Population-based studies of autism have found that Klinefelter's syndrome (KS), a common chromosome abnormality, is sometimes associated with autism. However, few detailed case descriptions of patients with KS and autism have not been published. Case Report In this paper, we describe the occurrence of autistic features in two cases of Klinefelter syndrome, one with the typical XXY karyotype and the other with the XXYY variant. Conclusion Autistic features may be more common in persons with Klinefelter syndrome than generally believed. We propose that all patients with KS should be screened for the presence of autism.