Letters to the Editor Anatomical Variations in the Circle of Willis and Migraine Susceptibility: Is There an Association? A Comment Dear Editor, We have been very interested by the comment from Schoonman et al concerning our work. 1 We fully agree with their comments about the frequency of incomplete circle of Willis (CW) in our control group which was lower than that observed in their own paper and in previous studies (although in their paper we noted for their healthy controls a discrepancy between the fre- quency of incomplete posterior CW in the text and in the table). 2 This difference in frequencies may be due to differ- ences in sample size (124 patients in our study and 44 patients in their study), inclusion criteria (patients recruited on the basis of a complaint of severe headache in our study vs healthy volunteers/patients in their study), and methods (all visualized CW vessels were considered to be present in our study, whereas in previous studies, only vessels >0.8 mm of diameter were considered present; no details concerning the definition of CW morphology is available in the paper by Schoonman et al). Furthermore, there is a notably higher rate of migraineurs with aura in our study than in the study by Schoonman et al (51% vs 16%); incomplete posterior CW was more frequent in this migraine subtype (65.2% vs 37.5%), but the difference did not reach statistical significance. Finally, although we con- sidered the CW to be complete in subjects with commu- nicant posterior arteries possessing a small diameter and low flow, such interpretation provides excellent interob- server agreement, a factor not mentioned in previous studies. In the end, we believe a large prospective study in the general population is required to examine the relation between CW morphology and migraine, a position which undoubtedly is shared by Schoonman et al. Jean-Marc Bugnicourt, MD; Pierre-Yves Garcia, MD; Candice Picard, MD; Olivier Godefroy, MD, PhD Department of Neurology, Amiens University Hospital, Amiens, France Johann Peltier, MD Department of Neurosurgery, Amiens University Hospital, Amiens, France Bruno Bonnaire, MD Department of Radiology, Amiens University Hospital, Amiens, France REFERENCES 1. Bugnicourt JM, Garcia PY, Peltier J, Bonnaire B, Picard C, Godefroy O. Incomplete posterior circle of Willis: A risk factor for migraine? Headache. 2009;49:879-886. 2. Schoonman GG, van Oosterhout WR, Ferrari MD, van der Grond J. Anatomical variations in the circle of Willis and Migraine Susceptibility: Is there an association? Headache. 2010;50:323. Cytokines in Idiopathic Intracranial Hypertension CSF We read with interest the article by Dhungana et al, 1 and can report further evidence for cytokine dysregulation in idiopathic intracranial hypertension (IIH) from our own experience. Cerebrospinal fluid (CSF) was obtained at diagnostic/ therapeutic lumbar puncture from 46 patients, comprising 11 patients with IIH, 5 with chronic inflammatory demyeli- nating peripheral neuropathy (CIDP), 7 with clinically iso- lated syndrome (CIS) suggestive of demyelination, and the remainder (23) with multiple sclerosis (MS) (4 primary pro- gressive, the remainder relapsing remitting or secondary progressive MS). Following lumbar puncture, CSF was centrifuged and the supernatant removed and stored at -80C. Cytokine 323