Compositions and methods for diagnosing autism

A diagnostic kit indicative of the predisposition for developing autism spectrum disorder in a human comprising:

• one or more detectably labeled oligonucleotide probes 17 to 100 nucleotides in length which are perfectly complementary to a target sequence comprising a single nucleotide polymorphism in the ENGRAILED 2 intronic sequence of SEQ ID NO:11, wherein the single nucleotide polymorphism is an A at position 2236 of SEQ ID NO:11;
• and
• one or more detectably labeled oligonucleotide probes 17 to 100 nucleotides in length which are perfectly complementary to a target sequence comprising a single nucleotide polymorphism in the ENGRAILED 2 intronic sequence of SEQ ID NO:11, wherein the single nucleotide polymorphism is a C at position 2388 of SEQ ID NO:11,
• wherein said probes are detectably labeled with a radioactive element, a chemical which fluoresces or an enzyme.