- Moderate intellectual disability (HP:0002342): Moderate intellectual disability (ID) is defined as a type of ID characterized by moderately sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 35-49. Evidence: PCS. Frequency: 1/1. (PMID:29392776)
- Dystonia (HP:0001332): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: PCS. Frequency: 4/4. (PMID:29392776;PMID:32467598)
- Seizure (HP:0001250): A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Evidence: PCS. Frequency: 2/2. Onset: Juvenile onset (HP:0003621). (PMID:32196122)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 3/3. (PMID:29392776;PMID:32196122)
- Ataxia (HP:0001251): 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. Frequency: 1/2. (PMID:32196122)
- Insomnia (HP:0100785): Persistent difficulty in starting or maintaining sleep, or waking up earlier than desired, despite having adequate opportunities and conditions for sleep. Evidence: PCS. Frequency: 1/2. (PMID:32196122)
- Aggressive behavior (HP:0000718): Behavior or an act aimed at harming a person, animal, or physical property (e.g., acts of physical violence; shouting, swearing, and using harsh language; slashing someone's tires). Evidence: PCS. Frequency: 1/2. (PMID:32196122)
- Paroxysmal dyskinesia (HP:0007166): Episodic bouts of involuntary movements with dystonic, choreic, ballistic movements, or a combination thereof. There is no loss of consciousness during the attacks. Evidence: PCS. Frequency: 3/3. (PMID:29392776;PMID:32467598)
- Motor stereotypy (HP:0000733): Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose. Evidence: PCS. Frequency: 2/2. (PMID:32196122)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 1/2. (PMID:32196122)
- Incoordination (HP:0002311): A deficit in coordination of muscle movements. Coordination is defined as the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. Evidence: PCS. Frequency: 1/1. (PMID:29392776)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 2/3. (PMID:32467598)
- Bruxism (HP:0003763): Bruxism is characterized by the grinding of the teeth including the clenching of the jaw and typically occur during sleep. Evidence: PCS. Frequency: 1/2. (PMID:32196122)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 1/2. (PMID:32196122)
- EEG abnormality (HP:0002353): Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp. Evidence: PCS. Frequency: 1/1. (PMID:29392776)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: PCS. Frequency: 5/5. (PMID:29392776;PMID:32196122;PMID:32467598)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: PCS. Frequency: 3/5. (PMID:32196122;PMID:32467598)
- Facial grimacing (HP:0000273). Evidence: PCS. Frequency: 1/1. (PMID:29392776)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: PCS. Frequency: 5/5. (PMID:32196122;PMID:32467598)
- Chorea (HP:0002072): Chorea (Greek for 'dance') refers to widespread arrhythmic involuntary movements of a forcible, jerky and restless fashion. It is a random-appearing sequence of one or more discrete involuntary movements or movement fragments. Movements appear random because of variability in timing, duration or location. Each movement may have a distinct start and end. However, movements may be strung together and thus may appear to flow randomly from one muscle group to another. Chorea can involve the trunk, neck, face, tongue, and extremities. Evidence: PCS. Frequency: 4/4. (PMID:29392776;PMID:32467598)
- Focal motor status epilepticus (HP:0032663): Status epilepticus with focal motor signs originating within networks limited to one hemisphere. Involves musculature in any form. The motor event could consist of an increase (positive) or decrease (negative) in muscle contraction to produce a movement. Evidence: PCS. Frequency: 1/3. (PMID:32467598)
- Inappropriate laughter (HP:0000748): Laughing that may be excessive and/or inappropriate in context (e.g., laughing at a funeral while others are crying). Evidence: PCS. Frequency: 1/2. (PMID:32196122)
- 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:29392776)
- Falls (HP:0002527). Evidence: PCS. Frequency: 2/4. (PMID:29392776;PMID:32467598)
- Focal-onset seizure (HP:0007359): A focal-onset seizure is a type of seizure originating within networks limited to one hemisphere. They may be discretely localized or more widely distributed, and may originate in subcortical structures. Evidence: PCS. Frequency: 1/1. (PMID:29392776)
These phenotypes are associated with the disease intellectual developmental disorder with paroxysmal dyskinesia or seizures (OMIM:619150).