The present invention is directed to polymorphisms in the MME gene (encoding metalo-membrane endopeptidase, neutral endopeptidase (NEP), enkephalinase) and the ANPEP gene (encoding amino peptidase N (APN), alanyl membrane aminopeptidase) or their gene products and to a process for the diagnosis of internalizing disorders. Internalizing disorders, such as depression, withdrawal, negative affect, anxiety, social problems, phobias, paranoid ideation, alcoholism and interpersonal sensitivity, are diagnosed in accordance with the present invention by analyzing the DNA sequences of the MME and/or ANPEP genes of an individual to be tested and comparing the respective DNA sequence to the known DNA sequence of a normal MME and/or ANPEP gene. Alternatively, the MME and ANPEP genes of an individual to be tested can be screened for mutations which cause internalizing disorders. Prediction of internalizing disorders will enable practitioners to treat internalizing disorders using existing medical therapy.
Polymorphisms associated with internalizing disorders