- Abnormality of the nervous system (HP:0000707): An abnormality of the nervous system. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:65683)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:65683)
- Psychomotor deterioration (HP:0002361): Loss of previously present mental and motor abilities. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:65683)
- Abnormal neuron morphology (HP:0012757): A structural anomaly of a neuron. Neurons are electrically excitable cells that transmit signals throughout the body. Neurons employ both electrical and chemical components in the transmission of information. Neurons are connected to other neurons at synapses and connected to effector organs or cells at neuroeffector junctions. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:65683)
- Brain imaging abnormality (HP:0410263): An anomaly of metabolism or structure of the brain identified by imaging. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:65683)
- Atypical behavior (HP:0000708): Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Mild intellectual disability (HP:0001256): Mild intellectual disability (ID) is defined as a type of ID characterized by mildly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 50-69. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Hemiparesis (HP:0001269): Loss of strength in the arm, leg, and sometimes face on one side of the body. Hemiplegia refers to a complete loss of strength, whereas hemiparesis refers to an incomplete loss of strength. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Focal impaired awareness seizure (HP:0002384): Focal impaired awareness seizure (or focal seizure with impaired or lost awareness) is a type of focal-onset seizure characterized by some degree (which may be partial) of impairment of the person's awareness of themselves or their surroundings at any point during the seizure. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Abnormal cortical gyration (HP:0002536): An abnormality of the gyri (i.e., the ridges) of the cerebral cortex of the brain. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Thick cerebral cortex (HP:0006891). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Hyperintensity of cerebral white matter on MRI (HP:0030890): A brighter than expected signal on magnetic resonance imaging emanating from the cerebral white matter. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Nocturnal seizures (HP:0031951): Seizures that occur while the affected individual is sleeping. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Cognitive impairment (HP:0100543): Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:65683)
- Generalized-onset seizure (HP:0002197): A generalized-onset seizure is a type of seizure originating at some point within, and rapidly engaging, bilaterally distributed networks. The networks may include cortical and subcortical structures but not necessarily the entire cortex. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:65683)
- Bilateral tonic-clonic seizure with focal onset (HP:0007334): A bilateral tonic-clonic seizure with focal onset is a focal-onset seizure which progresses into a bilateral tonic-clonic phase. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:65683)
- Severe intellectual disability (HP:0010864): Severe intellectual disability (ID) is defined as a type of ID characterized by severely sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 20-34. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:65683)
- Epileptic spasm (HP:0011097): A sudden flexion, extension, or mixed extension-flexion of predominantly proximal and truncal muscles that is usually more sustained than a myoclonic movement but not as sustained as a tonic seizure. Limited forms may occur: Grimacing, head nodding, or subtle eye movements. Epileptic spasms frequently occur in clusters. Infantile spasms are the best known form, but spasms can occur at all ages. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:65683)
- Infantile spasms (HP:0012469): Infantile spasms represent a subset of "epileptic spasms". Infantile Spasms are epileptic spasms starting in the first year of life (infancy). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:65683)
- Neuronal/glioneuronal neoplasm of the central nervous system (HP:0025170): A central nervous system neoplasm with neuronal and, less consistently, glial differentiation. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:65683)
These phenotypes are associated with the disease Isolated focal cortical dysplasia (ORPHA:65683).