Nicolaides-Baraitser syndrome: two new cases with autism spectrum disorder.

Nicolaides-Baraitser syndrome is a rare clinical condition characterized by mental retardation with impairment of expressive language, short stature, microcephaly, sparse hair, typical facial dysmorphisms, and interphalangeal joint swellings. To date 24 cases have been reported, most of them being sporadic. The genetic background of Nicolaides-Baraitser syndrome is unclear in terms of cause and mode of inheritance, one of the more probable explanations is de novo mutation of a dominant gene. Some reported patients presented autistic features, although in none of these patients was the diagnosis of autism spectrum disorder formally made. We describe two unrelated patients with clinical features suggesting Nicolaides-Baraitser syndrome and, in addition, autism spectrum disorder is defined by the presence of the three cardinal core features: qualitative impairments in social, communicative, and behavioral development.