Phenotypes associated with the disease Charcot-Marie-Tooth disease type 2B (OMIM:600882):
- Axonal degeneration/regeneration (HP:0003378): A pattern of simultaneous degeneration and regeneration of axons (see comment). Evidence: IEA. (OMIM:600882)
- Decreased motor nerve conduction velocity (HP:0003431): A type of decreased nerve conduction velocity that affects the motor neuron. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- 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: PCS. Frequency: 1/1. (PMID:17060578)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: TAS. (OMIM:600882)
- Somatic sensory dysfunction (HP:0003474): An abnormality of the primary sensation that is mediated by peripheral nerves (pain, temperature, touch, vibration, joint position). The word hypoesthesia (or hypesthesia) refers to a reduction in cutaneous sensation to a specific type of testing. Evidence: IEA. (OMIM:600882)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: TAS. (OMIM:600882)
- Fasciculations (HP:0002380): Fasciculations are observed as small, local, involuntary muscle contractions (twitching) visible under the skin. Fasciculations result from increased irritability of an axon (which in turn is often a manifestation of disease of a motor neuron). This leads to sporadic discharges of all the muscle fibers controlled by the axon in isolation from other motor units. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Sensorimotor neuropathy (HP:0007141). Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Foot dorsiflexor weakness (HP:0009027): Weakness of the muscles responsible for dorsiflexion of the foot, that is, of the movement of the toes towards the shin. The foot dorsiflexors include the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the peroneus tertius muscles. Evidence: IEA. (OMIM:600882)
- Autoamputation of foot (HP:0001868): The spontaneous detachment of a foot from the body due to long standing pathology. Evidence: IEA. (OMIM:600882)
- Pes planus (HP:0001763): A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced. Evidence: IEA. (OMIM:600882)
- Foot osteomyelitis (HP:0001886): An infection of bone of the foot. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Hammertoe (HP:0001765): Hyperextension of the metatarsal-phalangeal joint with hyperflexion of the proximal interphalangeal (PIP) joint. Evidence: IEA. (OMIM:600882)
- Hyporeflexia (HP:0001265): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: IEA. (OMIM:600882)
- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- 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: PCS. Frequency: 1/1. (PMID:17060578)
- Impaired distal tactile sensation (HP:0006937): A reduced sense of touch (tactile sensation) on the skin of the distal limbs. This is usually tested with a wisp of cotton or a fine camel's hair brush, by asking patients to say 'now' each time they feel the stimulus. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: IEA. (OMIM:600882)
- Peripheral axonal atrophy (HP:0003384): Atrophic changes of axons of the peripheral nervous system. Evidence: IEA. (OMIM:600882)
- 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: PCS. (OMIM:600882)
- Decreased compound muscle action potential amplitude (HP:0033383): Reduced level of the compound muscle action potential (CMAP), which is recorded following electrical stimulation of a nerve from surface electrodes overlying a muscle supplied by that nerve. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Distal lower limb muscle weakness (HP:0009053): Reduced strength of the distal musculature of the legs. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Autoamputation (HP:0001218): Auto-amputation is the spontaneous detachment of an appendage from the body due to long standing pathology. Evidence: IEA. (OMIM:600882)
- Peripheral neuropathy (HP:0009830): Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course. Evidence: IEA. (OMIM:600882)
- Sensory neuropathy (HP:0000763): Peripheral neuropathy affecting the sensory nerves. Evidence: IEA. (OMIM:600882)
- Absent Achilles reflex (HP:0003438): Absence of the Achilles reflex (also known as the ankle jerk reflex), which can normally be elicited by tapping the tendon is tapped while the foot is dorsiflexed. Evidence: PCS. Frequency: 1/1. (PMID:17060578)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:12545426)
- Dystrophic toenail (HP:0001810): Toenail changes apart from changes of the color of the toenail (nail dyschromia) that involve partial or complete disruption of the various keratinous layers of the nail plate. Evidence: IEA. (OMIM:600882)
- Distal lower limb amyotrophy (HP:0008944): Muscular atrophy of distal leg muscles. Evidence: PCS. Frequency: 1/1. (PMID:17060578)