Adv Genet
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Migraine is a severely debilitating episodic disorder affecting up to 12% of the general population. Migraine arises from both genetic and environmental factors, complicating our understanding of what makes the migraine brain susceptible to attacks. In recent years, powerful genetic screening tools have revealed several single genes linked to migraine. ⋯ In addition, the identification of monogenic subtypes has made it possible to generate suitable animal models for migraine. The purpose of this review is to present an overview of the clinical features of migraine and discuss the continuing highway of migraine gene discovery. The genes associated with FHM will be discussed, including what we have learned from studying the functional consequences of FHM mutations in cellular and animal models.
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Myotonia is a symptom of many different acquired and genetic muscular conditions that impair the relaxation phase of muscular contraction. Myotonia congenita is a specific inherited disorder of muscle membrane hyperexcitability caused by reduced sarcolemmal chloride conductance due to mutations in CLCN1, the gene coding for the main skeletal muscle chloride channel ClC-1. The disorder may be transmitted as either an autosomal-dominant or recessive trait with close to 130 currently known mutations. Although this is a rare disorder, elucidation of the pathophysiology underlying myotonia congenita established the importance of sarcolemmal chloride conductance in the control of muscle excitability and demonstrated the first example of human disease associated with the ClC family of chloride transporting proteins.
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Review
Genomic imprinting and the evolution of sex differences in mammalian reproductive strategies.
Two major developments have occurred that have influenced the evolution of sexually dimorphic reproductive strategies of mammals. Viviparity and development of a placenta is one such development, especially in small-brained rodent lineages, where there has been a major impact of placental hormones on the maternal brain. In the Old World primate/hominoid lineages, the massive expansion of the brain through growth of the neocortex has radically changed how reproductive strategies are determined. ⋯ The genetic basis for the expansion of neocortical development is complex, but those parts of the brain which have expanded are undoubtedly under the influence of imprinted genes, as studies using parthenogenetic and androgenetic chimeras and allometric analysis of brains across comparative phylogenies have shown. Sex differences in behavior owe much to social structure, social learning, and the deployment of intelligent behavioral strategies. The epigenetic effects of social learning on brain development have become equally as important as the epigenetic effects of hormones on brain development and both contribute to sex differences in behavior in large-brained primates.