Analysis of Lithuanian CYP2D6 polymorphism and its relevance to psychiatric care of the local population.

BACKGROUND

CYP450 system gene CYP2D6 polymorphisms have been associated with an altered response to psychotropic drugs. While there exists interindividual and interethnic differences of clinical significance, there is no data concerning the Lithuanian population.

AIMS

To determine the distribution of CYP2D6 alleles and predicted phenotype in the Lithuanian population, compare it to other Europeans and find the differences between patients with affective disorders and the healthy population.

METHODS

Our study sample consisted of 179 subjects that included 104 healthy volunteers and 75 patients with clinical diagnosis of affective disorders according to ICD-10AM classification, treated in hospital settings. DNA samples were taken from the blood and alleles of the CYP2D6 gene were determined for each participant. Frequencies were compared to other Europeans.

RESULTS

The frequency of the most common alleles *1 and *2 was 45.0% and 28.8% accordingly. Dysfunctional *5 (1 vs. 30, p < .002) allele was less frequent in Lithuania inhabitants than previously established in other Europeans. There were no polymorphisms of the CYP2D6 gene that could be associated with changes in drug metabolism in the patients. The functional CYP2D6 *2 allele was more prevalent in the control group, while the non functional CYP2D6 *4 allele was more prevalent in the patient group (p < .05 for both cases).

CONCLUSION

The genetic makeup of Lithuanians was generally comparable to other Europeans, but fewer Lithuanians had non-functional *5 allele. More patients had non-functional alleles. Study findings contradict previous results from other countries, where CYP2D6 gene polymorphism was associated with treatment outcomes.