Introduction

Variations in drug metabolism are based on constitutional, genetic and environmental factors; therefore, knowing the type and allelic frequencies of the CYP2D6 gene polymorphism in patients with Huntington's disease is relevant in the application and efficacy of available pharmacological treatments that are beneficial and improve their quality of life.

Aim

To establish the allelic and genotype frequencies of the CYP2D6 gene: *3, *4, *5 and *6 in a population sample of patients with Huntington's disease in Juan de Acosta, Colombia.

Material and methods

Cross- sectional study, with non- probabilistic convenience sampling consisting of 23 individuals: 10 patients with signs and symptoms of the condition, 5 relatives and 8 unrelated people. After signing the informed consent, DNA was isolated and quantified in peripheral blood samples using a UV- Vis spectrophotometer. The identification of polymorphism: *3, *4 and *6 was performed by Variant RFLP- conventional PCR and digestion with endonucleases. The *5 allele and CYP2D6 gene duplication were genotyped by multiplex real PCR.

Results

In the population sample, the CYP2D6 *4 and *6 alleles have frequencies 0.304 and 0.435, respectively; CYP2D6 *3 is monomorphic; assuming population genetic equilibrium, the frequency of the mutated allele *5 is 0.295 and 0.511, the CYP2D6 duplication.

Conclusions

The most represented genotype in the population was the wild type *1/*1 of CYP2D*3, homozygous, the genotype *4/*4 with mutated allele represents 30.4%; finally, a frequency of 26.1% with duplication/multiplication of active CYP2D6 alleles, a higher value than those reported in the Hispano-American and Colombian populations.