Identification of polymorphisms in the PCTG4 region of Xq13

Nucleic acid sequences within the q13 region of the X chromosome having polymorphisms associated with neuropsychiatric disorders and associated conditions are disclosed herein. One polymorphism occurs within the coding region of the HOPA gene and introduces a four amino acid insertion into a putative OPA domain, a domain which has been shown to be involved in tissue specific expression. Compositions including nucleic acids having these polymorphisms and antibodies to polymorphic regions within proteins encoded in the PCTG4 region are provided. Methods of using the information and nucleic acid sequences disclosed herein for the diagnosis and assessment of pathologies associated with neuropsychiatric disorders and associated conditions are also provided.