Patients with RIS generally do not experience symptoms (asymptomatic).
Causes and Risk Factors
When followed over a two year period, one third of patients with RIS develop a neurological event and are diagnosed with MS, one third develop a new finding on MRI without any symptoms, and one third show no change.
Since the risk of multiple sclerosis is significantly higher when a parent has been diagnosed with the disease, genetic factors may play a role. The unusual relationship between a person's geographic location during childhood and the risk of multiple sclerosis later in life suggests that there may be environmental factors at work in the disease.