Distal hereditary motor neuropathy, type V

Distal hereditary motor neuropathy, type V is a disorder that affects nerve cells (neurons) in the spinal cord. This condition specifically affects motor neurons, which are specialized cells that control muscle movement. Damage to motor neurons results in muscle weakness that worsens over time. In people with distal hereditary motor neuropathy, type V, this weakness primarily affects movement in the muscles that are furthest from the center of the body (distal muscles), such as the muscles in the hands and feet.

Signs and symptoms of distal hereditary motor neuropathy, type V usually begin during adolescence, but they can appear any time between infancy and the mid-30s. The first symptom of this condition is often cramps in the hands that are brought on by exposure to cold temperatures.

The characteristic features of distal hereditary motor neuropathy, type V are weakness and wasting (atrophy) of muscles of the hand, specifically on the side of the index finger near the thumb and in the palm of the hand at the base of the thumb.

About half of individuals with distal hereditary motor neuropathy, type V develop muscle weakness in the feet and lower legs. This can lead to problems with walking (gait disturbance), difficulty lifting the front part of the foot (foot drop), and a high foot arch (pes cavus).

People with distal hereditary motor neuropathy, type V can have exaggerated reflexes (hyperreflexia) or other disturbances in the nerves that are used to detect sensations (sensory neuropathy). Although sensory neuropathy is uncommon in people with distal hereditary motor neuropathy, type V, it is typical of a disorder called Charcot-Marie-Tooth disease. These two disorders have overlapping features and can also share a genetic cause. People with distal hereditary motor neuropathy, type V typically have a normal life expectancy.