- Bilateral tonic-clonic seizure (HP:0002069): A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Flat occiput (HP:0005469): Reduced convexity of the occiput (posterior part of skull). Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- EEG with spike-wave complexes (2.5-3.5 Hz) (HP:0010848): The presence of complexes of spikes and waves (2.5-3.5 Hz) in electroencephalography (EEG). Evidence: PCS. (PMID:29322246)
- Downslanted palpebral fissures (HP:0000494): The palpebral fissure inclination is more than two standard deviations below the mean. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- 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: PCS. Frequency: 1/2. (PMID:29322246)
- 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: 2/3. (PMID:29322246;PMID:31110234)
- Square face (HP:0000321): Facial contours, as viewed from the front, show a broad upper face/cranium and lower face/mandible, creating a square appearance. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Thick eyebrow (HP:0000574): Increased density/number and/or increased diameter of eyebrow hairs. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Full cheeks (HP:0000293): Increased prominence or roundness of soft tissues between zygomata and mandible. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Profound intellectual disability (HP:0002187): Profound intellectual disability (ID) is defined as a type of ID characterized by profoundly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) below 20. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- 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: 3/3. (PMID:29322246;PMID:31110234)
- Myoclonic seizure (HP:0032794): 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: 3/3. Onset: Childhood onset (HP:0011463). (PMID:29322246;PMID:31110234)
- EEG with polyspike wave complexes (HP:0002392): The presence of complexes of repetitive spikes and waves in EEG. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Tapered finger (HP:0001182): The gradual reduction in girth of the finger from proximal to distal. Evidence: PCS. Frequency: 1/3. (PMID:29322246;PMID:31110234)
- Increased theta frequency activity in EEG (HP:0031535): Increased frequency of theta wave activity in the electroencephalogram. Theta waves have a frequency of 3.5-7.5 Hertz, and are present in very small amounts in healthy waking adult EEGs. Theta activity is normal in small very amounts in the healthy waking adult EEG in a symmetrical distribution. Evidence: PCS. Frequency: 1/1. (PMID:31110234)
- Myoclonic absence seizure (HP:0011150): Myoclonic absence seizure is a type of generalized non-motor (absence) seizure characterized by an interruption of ongoing activities, a blank stare and rhythmic three-per-second myoclonic movements, causing ratcheting abduction of the upper limbs leading to progressive arm elevation, and associated with 3 Hz generalized spike-wave discharges on the electroencephalogram. Duration is typically 10-60 s. Whilst impairment of consciousness may not be obvious the ILAE classified this seizure as a generalized non-motor seizure in 2017. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Autistic behavior (HP:0000729): Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior. Evidence: PCS. Frequency: 2/2. (PMID:29322246)
- Anxiety (HP:0000739): Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control. Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Thick lower lip vermilion (HP:0000179): Increased thickness of the lower lip, leading to a prominent appearance of the lower lip. The height of the vermilion of the lower lip in the midline is more than 2 SD above the mean. Alternatively, an apparently increased height of the vermilion of the lower lip in the frontal view (subjective). Evidence: PCS. Frequency: 1/2. (PMID:29322246)
- Autosomal dominant inheritance (HP:0000006): 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:29322246)
These phenotypes are associated with the disease intellectual developmental disorder with seizures and language delay (OMIM:619000).