- 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:12112076)
- 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:145900)
- Ulnar claw (HP:0001178): An abnormal hand position characterized by hyperextension of the fourth and fifth fingers at the metacarpophalangeal joints and flexion of the interphalangeal joints of the same fingers such that they are curled towards the palm. Evidence: IEA. (OMIM:145900)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: TAS. (OMIM:145900)
- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: IEA. (OMIM:145900)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: TAS. (OMIM:145900)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Split hand (HP:0001171): A condition in which middle parts of the hand (fingers and metacarpals) are missing giving a cleft appearance. The severity is very variable ranging from slightly hypoplastic middle fingers over absent middle fingers as far as oligo- or monodactyl hands. Evidence: TAS. (OMIM:145900)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:145900)
- 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:145900)
- Distal sensory impairment (HP:0002936): An abnormal reduction in sensation in the distal portions of the extremities. Evidence: TAS. (OMIM:145900)
- Tongue fasciculations (HP:0001308): Fasciculations or fibrillation affecting the tongue muscle. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Decreased sensory nerve conduction velocity (HP:0003448): Reduced speed of conduction of the action potential along a sensory nerve. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Proximal muscle weakness (HP:0003701): A lack of strength of the proximal muscles. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- 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: PCS. Frequency: 1/1. (PMID:12112076)
- Hammertoe (HP:0001765): Hyperextension of the metatarsal-phalangeal joint with hyperflexion of the proximal interphalangeal (PIP) joint. Evidence: IEA. (OMIM:145900)
- Hyporeflexia (HP:0001265): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: IEA. (OMIM:145900)
- Kyphoscoliosis (HP:0002751): An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane. Evidence: IEA. (OMIM:145900)
- Broad-based gait (HP:0002136): An abnormal gait pattern in which persons stand and walk with their feet spaced widely apart. This is often a component of cerebellar ataxia. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- 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:145900)
- Onion bulb formation (HP:0003383): Repeated episodes of segmental demyelination and remyelination lead to the accumulation of supernumerary Schwann cells around axons, which is referred to as onion bulb formation. This finding affects peripheral nerves. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Hypertrophic nerve changes (HP:0003382). Evidence: IEA. (OMIM:145900)
- Segmental peripheral demyelination/remyelination (HP:0003481): A segmental pattern of demyelination and regeneration (remyelination) affecting peripheral nerves. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- 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: IEA. (OMIM:145900)
- Sensory ataxia (HP:0010871): Incoordination of movement caused by a deficit in the sensory nervous system. Sensory ataxia can be distinguished from cerebellar ataxia by asking the patient to close his or her eyes. Persons with cerebellar ataxia show only a minimal worsening of symptoms, whereas persons with sensory ataxia show a marked worsening of symptoms. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Peripheral demyelination (HP:0011096): A loss of myelin from the internode regions along myelinated nerve fibers of the peripheral nervous system. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Distal lower limb muscle weakness (HP:0009053): Reduced strength of the distal musculature of the legs. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Myelin tomacula (HP:0030175): The presence of multiple sausage-shaped swellings of the myelin sheath (The Latin tomaculum means sausage). Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- Autosomal recessive inheritance (HP:0000007): 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 individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:12112076)
- Increased CSF protein concentration (HP:0002922): Increased concentration of protein in the cerebrospinal fluid. Evidence: IEA. (OMIM:145900)
- Impaired distal vibration sensation (HP:0006886): A decrease in the ability to perceive vibration in the distal portions of the limbs. Evidence: PCS. Frequency: 1/1. (PMID:12112076)
- 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: IEA. (OMIM:145900)
These phenotypes are associated with the disease Charcot-Marie-Tooth disease type 3 (OMIM:145900).