Hereditary Neuropathy With Liability to Pressure Palsies (HNLPP)
(See also Overview of the Peripheral Nervous System.)
Hereditary neuropathy with liability to pressure palsies is a hereditary disorder in which nerves become increasingly sensitive to pressure, injury, and use.
In this disorder, nerves are easily damaged by slight pressure or injury or by repetitive use.
Numbness, tingling, and weakness occur in the affected area.
Electromyography and genetic testing help establish the diagnosis.
People should avoid or modify activities that cause symptoms, and wrist splints and elbow pads may help by reducing pressure on the affected nerves.
In this neuropathy, nerves are susceptible to damage resulting from relatively slight pressure or injury or from repetitive use.
Usually, this neuropathy starts during adolescence or young adulthood, but it may start at any age. It affects both sexes equally.
Hereditary neuropathy with liability to pressure palsies is usually inherited as an autosomal (not sex-linked) dominant trait. That is, only one gene from one parent is required for the disease to develop.
Nerves that run close to the body’s surface near a bone are commonly affected. For example, the following nerves may be affected:
Numbness, abnormal sensations (such as tingling), or weakness occurs periodically in the affected area. For example, peroneal nerve palsy weakens the muscles that lift the foot. As a result, people cannot lift the front part of their foot (a condition called footdrop) and may drag the front part of the foot along the ground as they walk.
Symptoms vary from unnoticeable and mild to severe and incapacitating. Episodes may last several minutes to months.
After an episode, about half of affected people recover completely, and most of the rest have mild symptoms.
Doctors may have difficulty diagnosing this neuropathy because the symptoms come and go. Electromyography and genetic testing help establish the diagnosis.
Rarely, biopsy of a nerve is required.