MG has a prevalence of around 20 per 100,000, so an average UK practice may expect to have only one patient. The condition is treatable. The incidence is bimodal with a 2:1 female to male ratio in the younger population and a reversed sex ratio over the age of 60. The reported incidence has been increasing since the mid-1980s, mainly because of increased recognition of late-onset disease. However, the condition is probably still underrecognised in the very elderly and may be mistaken for other disorders such as stroke, motor neurone disease or Parkinson's disease.