PLATELET MONOAMINE-OXIDASE ACTIVITY IN RELATION TO ALLELES OF DOPAMINE D-4 RECEPTOR AND TYROSINE-HYDROXYLASE GENES

Human personality characteristics and vulnerability to psychopathology are to a large extent dependent upon genetic factors which have yet t o be fully defined. The allele distribution of the dopamine D-4 recept or (D4DR) and thrombocyte monoamine oxidase (trbc MAO) activity have b oth been associated with personality traits which are supposedly relat ed, namely 'sensation seeking' according to Zuckerman and 'novelty see king' according to Cloninger, respectively. In this report, the D4DR a llele distribution and trbc MAO activity were studied in 31 psychiatri c patients and 21 control subjects. Trbc MAO activity is a biochemical marker of personality that has been shown to be under strong genetic influence. However, no association between the D4DR alleles and trbc M AO could be observed in this material. To our knowledge, this is the f irst report comparing these two markers, and based upon the results ob tained, we speculate that they may be connected with different types o f overlapping personality characteristics. The allele distribution of the tyrosine hydroxylase (TH) gene was also determined. TH is the rate -limiting enzyme in the biosynthesis of catecholamines, and it is beli eved to be involved in different kinds of psychopathology. No covariat ion between TH gene alleles and trbc MAO activity or D4DR alleles was observed in this material.