Abstract:
Background: Monoamine oxidase A (MAOA) has a role in metabolising different
biogenic amines, including dopamine. Functional studies have revealed the effect of
promoter region variants on the transcriptional activity of the MAOA that consequently
affects the homeostasis of the biogenic amines which might implicate in the aetiology of
multiple psychiatric conditions. Objectives: The current study aimed to determine the
influence of the promoter region 30 base pair (bp), a variable number of tandem repeats
(VNTR) of the MAOA, on its serum levels and association with schizophrenia (SHZ), bipolar
disorder (BD), and major depressive disorder (MDD) in the Pakistani population. Methods:
A total of 1062 subjects [MDD n = 416, BD n = 200, SHZ n = 97 and controls n = 349],
were genotyped for MAOA-30bp μVNTR through standard polymerase chain reaction
technique and logistic regression was applied to determine the genetic association. Serum
MAOA levels were determined through enzyme-linked immunosorbent assay (ELISA)
and the Mann-Whitney U test was applied. Results: In genotype analysis, eight different
repeat (R) alleles of MAOA-30 bp μVNTR were observed, where 4.5R, 5.5R, and 6R were
the rare repeats found in the current Pakistani cohort. In serum-based analysis the total
MAOA serum levels were found to be significantly elevated in SHZ; however, in sub-group
analysis, significantly higher serum levels of MAOA were observed only in the rare allele
groups of MDD, BD, and SHZ. Conclusions: The current study gives us further insights
into the complex nature of MAOA regulation and its genetic and serum-levels association
with different psychiatric conditions.
