Headache disability following trauma may be worsened by the presence of comorbid PTSD and has already been documented as more pronounced in those with preexisting primary headaches.9–11 Pre-injury migraine may be the greatest predictor of PTH frequency and severity,4,6,7,12 with chronic migraineurs being at greater risk than those with episodic migraine.13 Gender, age, and severity of TBI have also been shown to influence PTH.4,6,7,11,12,14 Gender and severity of injury interact and have a complex effect on PTH. The gene discussed is PTH; the disease is migraine disorder.