Determine whether single nucleotide polymorphisms (SNPs) of the calcitonin gene-related polypeptide (CGRP)-alpha (CALCA) and the receptor activity modifying protein-1 (RAMP1) are related to headache burden during the first week after concussion.

Post-traumatic headache is a commonly reported symptom after concussion.  SNPs related to CGRP are involved in the pathogenesis of migraine headaches and contribute to pain transmission and neurogenic inflammation. It is unclear in concussed persons if the headache burden is associated with genetic variations related to CGRP.  

A prospective study was performed in 34 concussed athletes (gender: 23 female, 11 male; age: 20±1 years; height: 1.75±0.12 meters; weight: 73±14 kilograms).  Participants completed the symptom evaluation checklist from the SCAT3 within 48 hours of injury (V1), and 4 (V2) and 7 (V3) days after injury. For each visit, the self-reported score (0-6) for headache, pressure in head, blurred vision, and sensitivity to light/noise were summed.  The area under-the-curve (AUC) was computed for the early (EHB: V1 to V2) and late (LHB: V2 to V3) burden of headache-related symptoms.  A saliva sample was obtained and a commercial laboratory identified the genotype for CALCA (rs3781719) and RAMP1 (rs10185142) using PMR-array. RAMP1 genotypes RAMP1 (TT, TC, CC) and CALCA (AA, AG, GG) genotypes were dichotomized (T+, T-, and A+, A- respectively) and concatenated (T+A+, T+A-, T-A+, T-A-) for analyses. 

A significant difference for EHB (p=0.003, partial η2= 0.417) was present across RAMP1+CALCA genotypes, but not for the LHB. The T+A+ subgroup had a significantly elevated EHB compared to the all-other subgroups [p<0.05: T+A+(n=16): 31.6±2.6; T+A-(n=9): 17.7±3.6; T-A+ (n=8): 18.4±3.7; T-A-(n=1): 0.0±0.0].  Gender served as a covariate and diagnosed concussion history had no impact

The current analysis provides a proof-of-concept to suggest that the combined T+A+ genoset from RAMP1+CALCA are associated with a greater headache burden in the first 4 days after concussion injury.