- Wide mouth (HP:0000154): Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Widely spaced teeth (HP:0000687): Increased spaces (diastemata) between most of the teeth in the same dental arch. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Hypopigmentation of the skin (HP:0001010): A reduction of skin color related to a decrease in melanin production and deposition. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- 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: Frequent (HP:0040282). (ORPHA:98795)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Lower limb hyperreflexia (HP:0002395): Increased intensity of the a reflex in the leg. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Poor speech (HP:0002465). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Hypopigmentation of hair (HP:0005599). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Iris hypopigmentation (HP:0007730): An abnormal reduction in the amount of pigmentation of the iris. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Protruding tongue (HP:0010808): Tongue extending beyond the alveolar ridges or teeth at rest. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Tongue thrusting (HP:0100703): Pressing forward of the tongue in the mouth, a retained motoric habit from infantile swallowing patterns. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98795)
- Mandibular prognathia (HP:0000303): Abnormal prominence of the chin related to increased length of the mandible. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Poor suck (HP:0002033): An inadequate sucking reflex, resulting in the difficult of newborns to be breast-fed. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Heat intolerance (HP:0002046): The inability to maintain a comfortable body temperature in warm or hot weather. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Broad-based gait (HP:0002136): An abnormal gait pattern in which persons stand and walk with their feet spaced widely apart. This is often a component of cerebellar ataxia. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Gait imbalance (HP:0002141). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Abnormal speech pattern (HP:0002167): An abnormality in the sound (volume) or cadence (rate) of speech. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Cessation of head growth (HP:0004485): Stagnation of head growth seen as flattening of the head circumference curve. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Secondary microcephaly (HP:0005484): Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Atypical absence seizure (HP:0007270): An atypical absence seizure is a type of generalized non-motor (absence) seizure characterized by interruption of ongoing activities and reduced responsiveness. In comparison to a typical absence seizure, changes in tone may be more pronounced, onset and/or cessation may be less abrupt, and the duration of the ictus and post-ictal recovery may be longer. Although not always available, an EEG often demonstrates slow (<3 Hz), irregular, generalized spike-wave activity. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Floppy infant (HP:0008947): Floppiness/hypotonia is defined as reduced resistance to passive movement of joints. Physical examination of floppy/hypotonic infants shows head lag, lack of shoulder and elbow muscle contraction on traction response, inability to tighten the shoulder girdle muscles (or slipping through) when held under the axillae, scarf sign (when the arm is pulled to the opposite side, the arm wraps around the neck with the elbow crossing midline), hyperdorsiflexion of the feet, easy apposition of the thumb against the forearm, feet touching the cheek with ease and without discomfort, frog leg position, and inverted U sign on ventral suspension (head, arms, and legs hanging down without elbow or knee flexion and the trunk rounded in a dome shape). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- EEG with focal epileptiform discharges (HP:0011185): EEG discharges recorded in particular areas of a localized (focal) abnormality in cerebral electrical activity recorded along the scalp by electroencephalography (EEG). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
- Bilateral tonic-clonic seizure with generalized onset (HP:0025190): 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98795)
These phenotypes are associated with the disease Angelman syndrome due to paternal uniparental disomy of chromosome 15 (ORPHA:98795).