Association Analysis of the Functional MAOA Gene Promoter and MAOB Gene Intron 13 Polymorphisms in Tension Type Headache Patients

Abstract

Background. Monoamine oxidase (MAO) enzymes play an important role in the etiology of many neurological diseases. Tension type headache (TTH) treatments contain inhibitors for selective re-uptake of serotonin and monoamine oxidase inhibitors. MAO (EC 1.4.3.4) has two isoenzymes known as MAOA and MAOB. A promoter polymorphism of a variable number of tandem repeats (VNTR) in the MAOA gene seems to affect MAOA transcriptional activity in vitro. Also, G/A polymorphism in intron 13 (rs1799836) of the MAOB gene have been previously found to be associated with the variability of MAOB enzyme activity. Objectives. The aim of our study was to investigate a possible association of monoamine oxidase (MAOA and MAOB) gene polymorphisms in tension type headache. Material and Methods. MAO gene polymorphisms were examined in a group of 120 TTH patients and in another 168 unrelated healthy volunteers (control group). MAOA promoter and MAOB intron 13 polymorphisms were genotyped using PCR-based methods. Results. An overall comparison between the genotype of MAOA and MAOB genes and allele frequencies of the patients and the control group did not reveal any statistically significant difference between the patients and the control group (p = 0.162). Conclusions. Factors like estrogen dosage, the limited number of male patients and other genes' neurotransmitters involved in the etiology of TTH could be responsible for our non-significant results