- Progressive (HP:0003676, a Human Phenotype Ontology term): 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:18976727)
- Juvenile onset (HP:0003621, a Human Phenotype Ontology term): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. (PMID:18976727)
- Dysmetria (HP:0001310, a Human Phenotype Ontology term): A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements. Evidence: IEA. (OMIM:612437)
- Generalized myoclonic seizure (HP:0002123, a Human Phenotype Ontology term): A generalized myoclonic seizure is a type of generalized motor seizure characterized by bilateral, sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus. Evidence: PCS. (PMID:18976727)
- Babinski sign (HP:0003487, a Human Phenotype Ontology term): Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Evidence: IEA. (OMIM:612437)
- Dysarthria (HP:0001260, a Human Phenotype Ontology term): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: IEA. (OMIM:612437)
- Atonic seizure (HP:0010819, a Human Phenotype Ontology term): Atonic seizure is a type of motor seizure characterized by a sudden loss or diminution of muscle tone without apparent preceding myoclonic or tonic event lasting about 1 to 2 seconds, involving head, trunk, jaw, or limb musculature. Evidence: TAS. (OMIM:612437)
- Ataxia (HP:0001251, a Human Phenotype Ontology term): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: PCS. (PMID:18976727)
- Autosomal recessive inheritance (HP:0000007, a Human Phenotype Ontology term): 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:18976727)
- Sensory axonal neuropathy (HP:0003390, a Human Phenotype Ontology term): An axonal neuropathy of peripheral sensory nerves. Evidence: IEA. (OMIM:612437)
- Tremor (HP:0001337, a Human Phenotype Ontology term): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: IEA. (OMIM:612437)
- Myoclonus (HP:0001336, a Human Phenotype Ontology term): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. (PMID:18976727)
These phenotypes are associated with the disease epilepsy, progressive myoclonic, 1B (OMIM:612437, an entry in Online Mendelian Inheritance in Man).