Cannon S C
Dept of Neurobiology, Harvard Medical School, Massachusetts General Hospital, Boston 02114, USA.
Trends Neurosci. 1996 Jan;19(1):3-10. doi: 10.1016/0166-2236(96)81859-5.
The myotonias and periodic paralyses are a diverse group of skeletal muscle disorders that share a common pathophysiological mechanism: all are caused by derangements in the electrical excitability of the sarcolemma. Mutations within coding regions of ion-channel genes have been identified recently as the underlying molecular defects in these heritable disorders. Chloride-channel mutations cause a reduction in the resting conductance, which enhances excitability and gives rise to myotonia. By contrast, missense mutations in the L-type Ca2+ channel reduce the electrical excitability of the fiber and cause a form of periodic paralysis. Mutations of the sodium channel impair inactivation of the channel, which, depending on the type and severity of the functional defect, results in either paralysis or myotonia.
肌强直和周期性麻痹是一组多样的骨骼肌疾病，它们具有共同的病理生理机制：均由肌膜电兴奋性紊乱所致。离子通道基因编码区域内的突变最近已被确定为这些遗传性疾病的潜在分子缺陷。氯离子通道突变导致静息电导降低，从而增强兴奋性并引发肌强直。相比之下，L型钙离子通道中的错义突变会降低肌纤维的电兴奋性，并导致一种周期性麻痹。钠通道突变会损害通道的失活，根据功能缺陷的类型和严重程度，这会导致麻痹或肌强直。
