Phenotypes associated with the disease Charcot-Marie-Tooth disease type 2B1 (ORPHA:98856):
- Distal sensory impairment (HP:0002936): An abnormal reduction in sensation in the distal portions of the extremities. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Decreased number of peripheral myelinated nerve fibers (HP:0003380): A loss of myelinated nerve fibers in the peripheral nervous system (in general, this finding can be observed on nerve biopsy). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Sensory axonal neuropathy (HP:0003390): An axonal neuropathy of peripheral sensory nerves. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Axonal loss (HP:0003447): A reduction in the number of axons in the peripheral nervous system. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- EMG: axonal abnormality (HP:0003482): Electromyographic (EMG) findings characteristic of axonal neuropathy, with normal or slightly decreased nerve conduction velocities, normal or slightly prolonged distal latencies, but significantly reduced motor potentials and sensory amplitudes. There may be spontaneous activity upon needle EMG studies, such as increased insertional activity, positive sharp waves, and fibrillation potentials. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Motor axonal neuropathy (HP:0007002): Progressive impairment of function of motor axons with muscle weakness, atrophy, and cramps. The deficits are length-dependent, meaning that muscles innervated by the longest nerves are affected first, so that for instance the arms are affected at a later age than the onset of deficits involving the lower leg. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Decreased amplitude of sensory action potentials (HP:0007078): A reduction in the amplitude of sensory nerve action potential. This feature is measured by nerve conduction studies. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Distal lower limb muscle weakness (HP:0009053): Reduced strength of the distal musculature of the legs. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Axonal degeneration (HP:0040078). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98856)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Abnormal foot morphology (HP:0001760): An abnormality of the skeleton of foot. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Pes cavus (HP:0001761): An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Hammertoe (HP:0001765): Hyperextension of the metatarsal-phalangeal joint with hyperflexion of the proximal interphalangeal (PIP) joint. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Steppage gait (HP:0003376): An abnormal gait pattern that arises from weakness of the pretibial and peroneal muscles due to a lower motor neuron lesion. Affected patients have footdrop and are unable to dorsiflex and evert the foot. The leg is lifted high on walking so that the toes clear the ground, and there may be a slapping noise when the foot strikes the ground again. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Decreased number of large peripheral myelinated nerve fibers (HP:0003387): A reduced number of large myelinated nerve fibers. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Proximal muscle weakness (HP:0003701): A lack of strength of the proximal muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Distal upper limb amyotrophy (HP:0007149): Muscular atrophy of distal arm muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Proximal lower limb amyotrophy (HP:0008956): Muscular atrophy affecting proximally located muscles of the legs, i.e., of the thigh. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Distal upper limb muscle weakness (HP:0008959): Reduced strength of the distal musculature of the arms. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Proximal lower limb muscle weakness (HP:0008994): A lack of strength of the proximal muscles of the legs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Peroneal muscle atrophy (HP:0009049): Atrophy of the peroneous muscles, peroneus longus (also known as Fibularis longus), Peroneus brevis (also known as fibularis brevis, and Peroneus tertius (also known as fibularis tertius). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Hand muscle atrophy (HP:0009130): Muscular atrophy involving the muscles of the hand. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Toe extensor amyotrophy (HP:0011916): Atrophy of the extensor digitorum longus muscles, which mediate extension of the toes. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Hand muscle weakness (HP:0030237): Reduced strength of the musculature of the hand. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98856)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98856)
- Shoulder girdle muscle atrophy (HP:0003724): Amyotrophy affecting the muscles of the shoulder girdle. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98856)
- Proximal amyotrophy (HP:0007126): Amyotrophy (muscular atrophy) affecting the proximal musculature. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98856)
- Decreased number of small peripheral myelinated nerve fibers (HP:0007249). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98856)
- Pelvic girdle muscle atrophy (HP:0008988): Muscular atrophy affecting the muscles that attach to the pelvic girdle (the gluteal muscles, the lateral rotators, adductor magnus, adductor brevis, adductor longus, pectineus, and gracilis muscles). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98856)
- Decreased motor nerve conduction velocity (HP:0003431): A type of decreased nerve conduction velocity that affects the motor neuron. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:98856)
Not associated with this disease:
- Clusters of axonal regeneration (HP:0007233): Groups of small caliber axons in peripheral nerve biospies indicative of axonal regeneration. Evidence: TAS. (ORPHA:98856)