To explore the role of single nucleotide polymorphisms (SNPs) for KIBRA and COMT on self-reported cognitive symptoms and the occurrence of orthostatic hypotension (OH) within 48 hours (48H) of concussion.

OH is associated with decreased cognitive function due to cerebral hypoperfusion.  Acute concussion injuries are associated cognitive impairment and autonomic dysfunction. Neither the relationship between these outcomes nor the impact of SNPs linked to cognitive impairment, such as KIBRA and COMT, has been explored after concussion.

A prospective study was performed in 36 concussed athletes (gender: 23 female, 13 male; age: 20±1 years; height: 1.75±0.12 meters; weight: 73±14 kilograms). Within 48H of injury, participants completed the SCAT3 and the self-reported score (0-6) for Fog, Difficulty Concentrating/Remembering and Confusion were summed for a “cognitive burden” score.  The ΔSBP was computed from an orthostatic challenge (supine to standing).  A saliva sample was obtained, and a commercial laboratory identified the genotype for KIBRA (rs17070145) and COMT (rs165599) using PMR-array. KIBRA (CC, TC, TT) and COMT (AA, AG, GG) genotypes were dichotomized (T+, T-, and G+, G- respectively) and concatenated (T+G+, T+G-, T-G+, T-G-) for analyses.

The omnibus model for ΔSBP in the concatenated KIBRA+COMT was significant (p<0.0001, power=0.993).  Post-hoc analyses revealed that the T+G+ subgroup had a significantly lower (p<0.001) ΔSBP (n=11; -23±11 mmHg) than the T+G-(n=8), T-G+(n=9), T-G-(n=8) subgroups (4±14, 5±17, and 1±14 mmHg, respectively). Cognitive burden was also significantly different between groups (p=0.03; power=0.753). Post-hoc analyses did not achieve statistical significance, but the T+G+ subgroup trended (p=0.09) toward having a lower cognitive burden (2.7±1.6) than the other subgroups (6.9±4.3, 5.7±4.9, and 6.9±5.8, respectively).

SNPs for KIBRA+COMT were associated with OH in the T+G+ group and an unexpected trend toward a lower cognitive burden than other groups 48H after concussion.  This combination of SNPs could play a role in cognitive resilience.