Major depressive disorder (MDD) is a prevalent and disabling psychiatric condition in Saudi Arabia, with genetic susceptibility remaining incompletely characterized. Reduced brain-derived neurotrophic Show more
Major depressive disorder (MDD) is a prevalent and disabling psychiatric condition in Saudi Arabia, with genetic susceptibility remaining incompletely characterized. Reduced brain-derived neurotrophic factor (BDNF) activity has been implicated in MDD. The Val66Met polymorphism (rs6265), involving the substitution of valine (Val, G allele) with methionine (Met, A allele), impairs activity-dependent BDNF secretion. This study examined the frequency of Val66Met and its association with MDD in a Saudi cohort. A case-control study was conducted, including 87 patients with MDD (44 males, 43 females; mean age 44.2 ± 11.5 years) and 87 healthy controls (39 males, 48 females; mean age 28.7 ± 8.4 years). Genotyping was performed using tetra-primer amplification refractory mutation system-polymerase chain reaction. Unadjusted and age- and sex-adjusted logistic regression analyses were applied under genotype-specific, dominant, recessive, and allelic models. The Val/Val (GG) genotype was more frequent in controls than patients (54.0% vs. 34.5%), whereas the Met/Met (AA) genotype was detected exclusively in patients (21.8% vs. 0%; χ The BDNF Val66Met polymorphism is associated with MDD susceptibility in Saudis. The Met (A) allele, particularly in homozygosity, confers increased risk, while the Val/Val genotype appears protective, supporting population-specific genetic contributions to depression. Show less