Future studies comparing migraine with PTH should further explore this finding, especially given the multifaceted relationships between the two headache types: (i) PTH often has symptoms that are very similar to migraine; (iii) migraine is a risk factor for developing PTH; and (iii) for those with pre-existing migraine, it can be difficult to differentiate post-injury migraine exacerbation from the development of post-injury PTH.20,51–53. The gene discussed is PTH; the disease is migraine disorder.