Diseases Studied

An autosomal dominant (inherited from one parent) disorder due to MPZ gene mutation which causes demyelination, or loss of myelin (the fatty coating) around extremity nerves. Symptoms manifest in early infancy (severe) or in adulthood (mild), including weakness, sensory loss, and muscle atrophy (wasting) of the lower legs; delayed walking in the infantile type; balance problems; hyporeflexia (decreased reflexes); lack of proprioception (spatial awareness of the limbs); and foot deformities requiring ankle braces to support walking.

An autosomal dominant (inherited from one parent) disorder due to MFN2 gene mutation affecting nerve axons (ends of the nerves) which carry signals from the brain to the extremities. Symptoms are more severe with earlier onset, including weakness, sensory loss, and muscle atrophy (wasting) of the lower legs; balance problems; hyporeflexia (decreased reflexes); and foot deformities requiring ankle braces to support walking. A few symptoms impact the central nervous system, including thinning of the spinal cord, hearing loss, and vision loss due to optic nerve atrophy.

A rare disorder with 9 subtypes affecting either axons (nerve ends) or myelin (fatty coating) of extremity nerves. Most forms of this disease are autosomal dominant (inherited from one parent), but these nine subtypes are autosomal recessive (inherited from both parents). Symptoms include weakness, sensory loss, and muscle atrophy (wasting) of the lower legs; hypotonia (low muscle tone); scoliosis (abnormal spinal curvature sideways); steppage gait (lifting the legs high to avoid tripping over dragging toes); and foot deformities requiring ankle braces to support walking.

A rare disorder causing demyelination, or loss of myelin (the fatty coating) around extremity nerves. There are 6 subtypes, each with mutations occurring on the X chromosome (X-linked inheritance). Symptoms include lower leg and hand muscle weakness, sensory loss, and muscle atrophy (wasting); ataxia (lack of coordination); hyporeflexia (decreased reflexes); hearing loss; vision loss due to optic nerve atrophy; intellectual deficit; and spastic paraplegia (weakness and stiffness in the leg muscles).

A term indicating nerve damage resulting in muscle weakness, muscle atrophy (wasting), and abnormal sensations such as numbness, tingling, pins and needles, and pain in affected regions. Peripheral means "away from the center" and refers to the peripheral nervous system (PNS). The PNS encompasses all nerves branching off the central nervous system (CNS). The CNS includes only the brain and spinal cord. Peripheral nerves travel down to the feet and hands (the periphery of the body). Charcot Marie Tooth Disease is a disorder with this type of nerve dysfunction.

A rare, inherited disorder in which the cause (usually a specific gene mutation) is known. The hallmark characteristic is damage to nerve axons (nerve ends) or myelin (fatty coating around nerves) in the extremities. Symptoms include weakness, sensory loss, and muscle atrophy (wasting) of the lower legs; balance problems; hyporeflexia (decreased reflexes); lack of proprioception (spatial awareness of the limbs); and foot deformities requiring ankle braces to support walking.

A rare disorder in which the cause of the disease is unknown. It is either inherited (passed on to a child from one or both parents) or sporadic (occurring spontaneously in an individual over time). The hallmark characteristic is damage to nerve axons (nerve ends) or myelin (fatty coating around nerves) in the extremities. Symptoms include lower leg muscle weakness, sensory loss, and atrophy (wasting); balance problems; hyporeflexia (decreased reflexes); lack of proprioception (spatial awareness of the limbs); and foot deformities requiring ankle braces to support walking.

A term indicating damage to nerves that branch off from the central nervous system (brain and spinal cord). These nerves travel away from the center of the body all the way to the feet and hands (the periphery of the body). Symptoms include muscle weakness, muscle atrophy (wasting), and abnormal sensations such as numbness, tingling, pins and needles, and pain in affected regions. An inherited example of this disorder is Charcot Marie Tooth Disease, which is characterized by foot drop, trouble walking, foot deformities, abnormal sensations in the hands and feet, and loss of fine motor skills.