- Abnormal foot morphology (HP:0001760): An abnormality of the skeleton of foot. Evidence: TAS. (OMIM:137200)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: IEA. (OMIM:137200)
- Elevated circulating creatine kinase activity (HP:0003236): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 12/14. (PMID:22961002)
- Myokymia (HP:0002411): Myokymia consists of involuntary, fine, continuous, undulating contractions that spread across the affected striated muscle. Evidence: PCS. Frequency: 2/50. (PMID:22961002)
- Progressive (HP:0003676): Applies to a disease manifestation that increases in scope or severity over the course of time, i.e., that worsens with age. Evidence: PCS. (PMID:22961002)
- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 44/50. (PMID:22961002)
- Muscle stiffness (HP:0003552): A condition in which muscles cannot be moved quickly without accompanying pain or spasm. Evidence: PCS. (PMID:22961002)
- Muscle spasm (HP:0003394): Sudden and involuntary contractions of one or more muscles. Evidence: PCS. (PMID:22961002)
- 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: TAS. (OMIM:137200)
- Sensory axonal neuropathy (HP:0003390): An axonal neuropathy of peripheral sensory nerves. Evidence: PCS. (PMID:22961002)
- Neuromyotonia (HP:0034351): Peripheral nerve hyperexcitability manifesting as spontaneous discharges originating from motor axons or their terminals, lead to overactivity of muscles, typically manifesting as twitches, cramps and stiffness. Evidence: PCS. Frequency: 44/46. (PMID:22961002)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 4/50. (PMID:22961002)
- Young adult onset (HP:0011462): Onset of disease at the age of between 16 and 40 years. Evidence: PCS. Frequency: 2/50. (PMID:22961002)
- 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: TAS. (OMIM:137200)
- 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:22961002)
- Distal sensory impairment (HP:0002936): An abnormal reduction in sensation in the distal portions of the extremities. Evidence: PCS. Frequency: 23/28. (PMID:22961002)
- Hyperhidrosis (HP:0000975): Abnormal excessive perspiration (sweating) despite the lack of appropriate stimuli like hot and humid weather. Evidence: IEA. (OMIM:137200)
These phenotypes are associated with the disease Gamstorp-Wohlfart syndrome (OMIM:137200).