- Status epilepticus (HP:0002133, a Human Phenotype Ontology term): Status epilepticus is a type of prolonged seizure resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms which lead to abnormally prolonged seizures (after time point t1). It is a condition that can have long-term consequences (after time point t2), including neuronal death, neuronal injury, and alteration of neuronal networks, depending on the type and duration of seizures. Evidence: PCS. Frequency: 1/2. (PMID:31056671)
- Hypoplasia of the corpus callosum (HP:0002079, a Human Phenotype Ontology term): Underdevelopment of the corpus callosum. Evidence: PCS. Frequency: 2/2. (PMID:31056671)
- Seizure (HP:0001250, a Human Phenotype Ontology term): 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: Infantile onset (HP:0003593, a Human Phenotype Ontology term). (PMID:31056671)
- Cerebral cortical atrophy (HP:0002120, a Human Phenotype Ontology term): Atrophy of the cortex of the cerebrum. Evidence: PCS. Frequency: 1/2. (PMID:31056671)
- Global developmental delay (HP:0001263, a Human Phenotype Ontology term): 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: 2/2. (PMID:31056671)
- Secondary microcephaly (HP:0005484, a Human Phenotype Ontology term): Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth. Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Myoclonic seizure (HP:0032794, a Human Phenotype Ontology term): A myoclonic seizure is a type of motor seizure characterized by 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. Frequency: 1/1. (PMID:29961870)
- Generalized hypotonia (HP:0001290, a Human Phenotype Ontology term): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Bilateral tonic-clonic seizure with generalized onset (HP:0025190, a Human Phenotype Ontology term): A bilateral tonic-clonic seizure with generalized onset is a type of bilateral tonic-clonic seizure characterized by generalized onset; these seizures rapidly engage networks in both hemispheres at the start of the seizure. Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Motor delay (HP:0001270, a Human Phenotype Ontology term): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 2/2. (PMID:31056671)
- Migrating focal seizure (HP:0032786, a Human Phenotype Ontology term): A migrating focal seizure is a seizure that involves different body parts, usually without overlap, in a consecutive manner so that the offset of a seizure in one part coincides with its onset in another, even shifting multiple times between the sides of the body. They can be associated with autonomic manifestations. Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Severe intellectual disability (HP:0010864, a Human Phenotype Ontology term): 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: PCS. Frequency: 2/2. (PMID:31056671)
- Tonic seizure (HP:0032792, a Human Phenotype Ontology term): A tonic seizure is a type of motor seizure characterized by unilateral or bilateral limb stiffening or elevation, often with neck stiffening. Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Autism (HP:0000717, a Human Phenotype Ontology term): Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV). Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Frontotemporal cerebral atrophy (HP:0006892, a Human Phenotype Ontology term): Atrophy (wasting, decrease in size of cells or tissue) affecting the frontotemporal cerebrum. Evidence: PCS. Frequency: 1/2. (PMID:31056671)
- CNS hypomyelination (HP:0003429, a Human Phenotype Ontology term): Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis. Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Spasticity (HP:0001257, a Human Phenotype Ontology term): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: PCS. Frequency: 1/1. (PMID:29961870)
- Autosomal dominant inheritance (HP:0000006, 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 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: PCS. (PMID:31056671)
These phenotypes are associated with the disease developmental and epileptic encephalopathy, 79 (OMIM:618559, an entry in Online Mendelian Inheritance in Man).