2nd Workshop Neurogenetics in Germany, Munich, October 19-21, 1995
The aim of our study is to find polymorphic variations in neurotransmitter receptor genes and analyse their role in liability to develop neuropsychiatric disorders and in determining response to medications.
As mutation scanning procedures we are using single strand conformation analysis (SSCA) and heteroduplex analysis. We are currently screening DNA samples from 184 unrelated individuals including patients with bipolar affective disorder, schizophrenia, and Tourette's syndrome as well as healthy controls. Extended patient and control samples are available for further association analysis.
As part of our mutation screening programme we investigated the genes coding for the dopamine Dl and D4 receptors as well as the genes coding for serotonin 5-HT1A, 5-HT1D , 5-HT1E, and 5-HT1F receptors. Mutations leading to genetic variants of the D4 (Gly11Arg, 235del13), 5HT1A (I28V), and 5HT1D (F124C) receptor proteins were identified. Analysis of the D1, 5HT1E, and 5HT1F receptor genes revealed only silent mutations. The 235del13 mutation in the D4 gene is of specific interest since it is predicted to result in a truncated non-functional receptor protein. To address the question whether these mutations might contribute to the development of common neuropsychiatric disorders we determined frequencies in patients with schizophrenia, manic depression, Tourette's syndrome, and healthy controls. However, all mutations were observed in similar frequencies in patients and controls, indicating that none of these mutations is causally related to major psychiatric diseases.
Future studies will examine variation in other genes involved in the dopaminergic or serotonergic pathways.
This work is supported by the Deutsche Forschungsgemeinschaft (SFB 400 "Molekulare Grundlagen zentralnervöser Erkrankungen", Teilprojekt A3).
dopamine and serotonin receptor genes