Anti-GM1 antibodies are found in the serum of GBS patients. GBS following CMV infections has anti GM2 antibodies. Though easy to diagnose in its classical form, GBS is often missed because of atypical clinical features which include ophthalmoplegia, ataxia, sensory loss and dysautonomia. Ten percent of those who recover have residual weakness. In chronic cases, there is significant axon loss.
Inflammation is variable, sometimes absent.
In the active phase of the disease, the CSF shows elevated protein. There are standardized criteria for their diagnosis, based on the clinical, CSF, nerve conduction and biopsy findings. It involves 1 in 2500 persons and is autosomal dominant. It begins in childhood or adolescence and progresses slowly, involving other nerves. It is compatible with a normal lifespan.