About MMN

Multifocal Motor Neuropathy (MMN) is a rare disorder in which motor nerves (the ones controlling your muscles) are attacked by your own immune system. This makes it hard for the nerves to send the electrical signals that move your body.

MMN 101 from the GBS|CIDP Foundation International

Symptoms

Typically, MMN is slowly progressive, resulting in asymmetrical weakness of a patient’s limbs. Symptoms are usually first found in the arms and hands, but may eventually affect the legs and feet. Patients frequently develop weakness in their hand(s), resulting in dropping of objects or sometimes inability to turn a key in a lock.

The weakness associated with MMN can be recognised as fitting a specific nerve territory. There is essentially no numbness, tingling, or pain. Patients with MMN can have other symptoms, including twitching, or small random dimpling of the muscle under the skin which neurologists call fasciculations.

Incidence

MMN is chronically progressive without remission. It affects both men and women, although men are more frequently affected than women by a ratio of about 2.7:1. Men also tend to be diagnosed at a younger age. The median age of onset is 40 years old, although the disorder has been reported individuals ranging from 20-80 years of age. In a handful of instances, the disorder has occurred in children (pediatric cases). Multifocal motor neuropathy is estimated to affect about 0.6 per 100,000 in the general population. Because rare disorders often go undiagnosed or misdiagnosed, determining their true frequency in the general population is difficult.

Diagnosis

MMN is very difficult to diagnose and sometimes symptoms can be confused with Motor Neuron Disease and other similar conditions.

Treatment

Treatment for MMN generally involves giving patients regular doses of Intravenous immunoglobulin (IVIG) a preparation of antibodies obtained from healthy volunteers. The treatment usually does not completely reverse all of the symptoms, and those patients who do respond will require repeated treatments to maintain their improvement. Patients usually require treatment every 2-5 weeks and over time may need increased doses of IVIg. A very expensive treatment.

Cure

Despite 30 years of research since MMN was first identified, there are still many questions to be answered about what causes it and much to do before a cure can be identified.

To learn more go to the GBS|CIDP Foundation International