Genetic modulation of longitudinal change in neurocognitive function among adult glioma patients

Impaired neurocognitive function (NCF) is extremely common in patients with higher grade primary brain tumor. We previously reported evidence of genetic variants associated with NCF in glioma patients prior to treatment. However, little is known about the effect of genetic variants on NCF decline after adjuvant therapy.

Patients (N = 102) completed longitudinal NCF assessments that included measures of verbal memory, processing speed, and executive function. Testing was conducted in the postoperative period with an average follow up interval of 1.3 years. We examined polymorphisms in 580 genes related to five pathways (inflammation, DNA repair, metabolism, cognitive, and telomerase).

Five polymorphisms were associated with longitudinal changes in processing speed and 14 polymorphisms with executive function. Change in processing speed was strongly associated with MCPH1 rs17631450 (P = 2.2 × 10^-7) and CCDC26 rs7005206 (P = 9.3 × 10^-7) in the telomerase pathway; while change in executive function was more strongly associated with FANCF rs1514084 (P = 2.9 × 10^-6) in the DNA repair pathway and DAOA rs12428572 (P = 2.4 × 10^-5) in the cognitive pathway. Joint effect analysis found significant genetic-dosage effects for longitudinal changes in processing speed (P_trend = 1.5 × 10^-10) and executive function (P_trend = 2.1 × 10^-11). In multivariable analyses, predictors of NCF decline included progressive disease, lower baseline NCF performance, and more at-risk genetic variants, after adjusting for age, sex, education, tumor location, histology, and disease progression.

Our longitudinal analyses revealed that polymorphisms in telomerase, DNA repair, and cognitive pathways are independent predictors of decline in NCF in glioma patients.