Does the level of LDL cholesterol moderate a relationship between DRD4 and novelty seeking?

This study examined the role of low density lipoprotein (LDL) cholesterol level in the association between Dopamine D4 receptor (DRD4) polymorphism and temperament dimension novelty seeking. From the on-going population based study of “Cardiovascular Risk in Young Finns”, 78 men and women responded to the novelty seeking scale of the temperament and character inventory [Archives of General Psychiatry 44 (1987) 573] and were apolipoprotein E (apoE) and DRD4 genotyped. DRD4 polymorphism was related to disorderliness, a component of novelty seeking, in subjects with high LDL cholesterol level but not in subjects with low LDL cholesterol level. This finding did not change after adjustment for apoE polymorphism. Our findings suggest that the genetic determination of temperament may be dependent on biological factors, such as LDL cholesterol.