Phenotypes associated with the disease developmental and epileptic encephalopathy, 55 (OMIM:617599):
- Poor head control (HP:0002421): Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months. Evidence: IEA. (OMIM:617599)
- Hypsarrhythmia (HP:0002521): Hypsarrhythmia is abnormal interictal high amplitude waves and a background of irregular spikes. There is continuous (during wakefulness), high-amplitude (>200 Hz), generalized polymorphic slowing with no organized background and multifocal spikes demonstrated by electroencephalography (EEG). Evidence: IEA. (OMIM:617599)
- Clonus (HP:0002169): A series of rhythmic and involuntary muscle contractions (at a frequency of about 5 to 7 Hz) that occur in response to an abruptly applied and sustained stretch. Evidence: IEA. (OMIM:617599)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: IEA. (OMIM:617599)
- Flexion contracture (HP:0001371): A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints. Evidence: IEA. (OMIM:617599)
- 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: IEA. (OMIM:617599)
- 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: IEA. (OMIM:617599)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: IEA. (OMIM:617599)
- Multifocal epileptiform discharges (HP:0010841): An abnormality in cerebral electrical activity recorded along the scalp by electroencephalography (EEG) and being identified at multiple locations (foci). Evidence: IEA. (OMIM:617599)
- Cerebral visual impairment (HP:0100704): A form of loss of vision caused by damage to the visual cortex rather than a defect in the eye. Evidence: IEA. (OMIM:617599)
- Reduced eye contact (HP:0000817): A reduced frequency or duration of eye contact. Evidence: TAS. (PMID:28334793)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: IEA. (OMIM:617599)
- Neonatal onset (HP:0003623): Onset of signs or symptoms of disease within the first 28 days of life. Evidence: IEA. (OMIM:617599)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: IEA. (OMIM:617599)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: IEA. (OMIM:617599)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: IEA. (OMIM:617599)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: IEA. (OMIM:617599)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: TAS. (PMID:28334793)
- Joint hypermobility (HP:0001382): The capability that a joint (or a group of joints) has to move, passively and/or actively, beyond normal limits along physiological axes. Evidence: TAS. Frequency: 20/20. (OMIM:617599;PMID:28334793)
- 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: IEA. (OMIM:617599)
- Decreased head circumference (HP:0040195): An abnormally reduced head circumference in a growing child. Head circumference is measured with a nonelastic tape and comprises the distance from above the eyebrows and ears and around the back of the head. The measured HC is then plotted on an appropriate growth chart. Microcephaly is defined as a head circumference (HC) that is great than two standard deviations below the mean of age- and gender-matched population based samples. Severe microcephaly is defined with an HC that is three standard deviations below the mean. Evidence: TAS. (PMID:28334793)
- Limb hypertonia (HP:0002509). Evidence: IEA. (OMIM:617599)
- 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: IEA. (OMIM:617599)
- Epileptic encephalopathy (HP:0200134): A condition in which epileptiform abnormalities are believed to contribute to the progressive disturbance in cerebral function. Epileptic encephalaopathy is characterized by (1) electrographic EEG paroxysmal activity that is often aggressive, (2) seizures that are usually multiform and intractable, (3) cognitive, behavioral and neurological deficits that may be relentless, and (4) sometimes early death. Evidence: IEA. (OMIM:617599)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: TAS. (PMID:28334793)