Phenotypes associated with the disease Charcot-Marie-Tooth disease X-linked recessive 2 (OMIM:302801):
- Decreased motor nerve conduction velocity (HP:0003431): A type of decreased nerve conduction velocity that affects the motor neuron. Evidence: IEA. (OMIM:302801)
- 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: IEA. (OMIM:302801)
- 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: IEA. (OMIM:302801)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: IEA. Frequency: Occasional (HP:0040283). (OMIM:302901)
- Upper limb muscle weakness (HP:0003484): Weakness of the muscles of the arms. Evidence: IEA. (OMIM:302901)
- 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: IEA. (OMIM:302801)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: IEA. (OMIM:302801)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: IEA. (OMIM:302801)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: IEA. (OMIM:302801)
- X-linked recessive inheritance (HP:0001419): A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele. Evidence: IEA. (OMIM:302801)
- 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:302801)
- 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:302801)
- Distal sensory impairment (HP:0002936): An abnormal reduction in sensation in the distal portions of the extremities. Evidence: IEA. (OMIM:302801)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: IEA. Frequency: Occasional (HP:0040283). (OMIM:302901)