The results of a clinical trial conducted by neurologists of Hospital da Luz Lisboa on cluster headache confirmed it to be related with the CLOCK gene , which is involved in the regulation of the circadian rhythm. The results of this study have recently been published in Cephalalgia, the official journal of the International Headache Society. “ This clinical trial was only possible through to the participation of patients followed in the Headache Centre of Hospital da Luz Lisboa , whose outstanding collaboration I take the opportunity to thank. In fact, this sharing in Cephalalgia is not only a recognition, but also views to divulge the results to the very participants, since the participation in clinical trials is subject to strict rules of confidentiality”, states the director of the Centre and lead researcher of the project, Raquel Gil-Gouveia . The study was published in the April edition of Cephalalgia and has for title “ CLOCK gene circannual expression in cluster headache ” ( link ). Its authors, besides Raquel Gil-Gouveia, Renato Oliveira and Ana Neves Costa, Tiago Paixão, Dora Pedroso, André B. Barros and Luís F. Moita (these last five researchers from the Instituto Gulbenkian de Ciência). Cluster headache : Is an extremely intense headache located in the forehead area and only on one side of the head; Affects mostly men; Crises have a pattern of occurrence related with the time of the day or time of the year – that is, in the same individual, they tend to occur always at the same hour (between midnight and 3 in the morning, usually) or the same time of the year (spring and autumn, usually). It is known now that there are genes involved in the regulation of the circadian rhythm (the natural rhythm of sleep/wake), namely the CLOCK gene. The pattern of the cluster headache crises and the fact that we already know that this gene and others of the same group are related with several brain functions (such as sleep, response to stress, learning and memory, for instance), raised the question of a possible influence also on cluster headache. In this clinical trial, the variation of the CLOCK gene expression was studied along a minimum period of one year, in a group of 50 individuals diagnosed with cluster headache (84% men) and followed up in neurology consultation, comparatively to a control group of individuals (86% men) with similar alcohol, smoke and coffee consumption habits, but with no cluster headache, all of them followed up at Hospital da Luz Lisboa or recruited for the study. The conclusions were the following: It was observed that the variation of the CLOCK gene along the year occurred in the same sense in all the individuals studied, but fluctuations were much milder in the subjects with cluster headache. The results support the hypothesis that the CLOCK gene is related with the disease and that the individuals with cluster headache studied have their ability of adaptation to the circadian rhythms and environmental variations compromised, which may explain the seasonal characteristics of the disease. “ CLOCK gene circannual expression in cluster headache ”
