Background:
Mild traumatic brain injury (mTBI) often results in
post-concussion symptoms,
chronic pain, and
sleepiness. Genetic factors are thought to play an important role in poor prognosis. Aims: The aims of this study are to (1) document the prevalence of
pain and
post-concussion symptoms in mTBI patients in acute and chronic phases (2) determine whether candidate genes predispose to
post-concussive symptoms and
pain. Methods: Posttraumatic symptoms, evaluated using the Rivermead
Post-Concussion Symptoms Questionnaire, and
pain were assessed in 94 mTBI patients in the acute phase as well as in 22 healthy controls. Assessment was repeated in 36 patients after one year who agreed to participate in the follow-up visit. Gene polymorphisms and expression were assessed in mTBI patients and healthy controls. Results: In the acute phase, mTBI patients with
pain (69%) presented more psychological symptoms and
sleepiness and were less able to return to work than those without
pain. At one year, 19% of mTBI patients had persistent
pain and psychological distress. Two haplotypes (H2 and H3) in the
brain-derived neurotrophic factor (
BDNF) gene were shown to be respectively deleterious and protective against
post-concussion symptoms and
pain in both acute and chronic phases. Protective haplotype H3 was associated with a decreased expression of the anti-sense of
BDNF (
BDNF-AS). Deleterious haplotype H2 predicted the development of
chronic pain at one year, whereas H3 was protective. Conclusions: This pilot study suggests a protective mechanism of a multilocus effect in
BDNF, through
BDNF-AS, against
post-concussion symptoms and
pain in the acute phase and possibly
chronic pain at one year post-mTBI. The role of
antisense RNA should be validated in larger cohorts.