- Encephalopathy (HP:0001298, a Human Phenotype Ontology term): Encephalopathy is a term that means brain disease, damage, or malfunction. In general, encephalopathy is manifested by an altered mental state. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Congenital onset (HP:0003577, a Human Phenotype Ontology term): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 2/3. (PMID:28777934)
- Hypsarrhythmia (HP:0002521, a Human Phenotype Ontology term): 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: PCS. Frequency: 1/3. (PMID:28777934)
- Progressive (HP:0003676, a Human Phenotype Ontology term): Applies to a disease manifestation that increases in scope or severity over the course of time, i.e., that worsens with age. Evidence: PCS. (PMID:28777934)
- Hearing impairment (HP:0000365, a Human Phenotype Ontology term): A decreased magnitude of the sensory perception of sound. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Dystonia (HP:0001332, a Human Phenotype Ontology term): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Cerebral cortical atrophy (HP:0002120, a Human Phenotype Ontology term): Atrophy of the cortex of the cerebrum. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- 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: 1/3. (PMID:28777934)
- Agenesis of corpus callosum (HP:0001274, a Human Phenotype Ontology term): Absence of the corpus callosum as a result of the failure of the corpus callosum to develop, which can be the result of a failure in any one of the multiple steps of callosal development including cellular proliferation and migration, axonal growth or glial patterning at the midline. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Infantile onset (HP:0003593, a Human Phenotype Ontology term): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 1/3. (PMID:28777934)
- Hypoplasia of the pons (HP:0012110, a Human Phenotype Ontology term): Underdevelopment of the pons. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Cerebral visual impairment (HP:0100704, a Human Phenotype Ontology term): A form of loss of vision caused by damage to the visual cortex rather than a defect in the eye. Evidence: PCS. Frequency: 2/3. (PMID:28777934)
- Ventriculomegaly (HP:0002119, a Human Phenotype Ontology term): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Axial hypotonia (HP:0008936, a Human Phenotype Ontology term): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Neurogenic bladder (HP:0000011, a Human Phenotype Ontology term): A type of bladder dysfunction caused by neurologic damage. Neurogenic bladder can be flaccid or spastic. Common manifestatios of neurogenic bladder are overflow incontinence, frequency, urgency, urge incontinence, and retention. Evidence: PCS. Frequency: 1/3. (PMID:28777934)
- Dysphagia (HP:0002015, a Human Phenotype Ontology term): Difficulty in swallowing. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Microcephaly (HP:0000252, a Human Phenotype Ontology term): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Scoliosis (HP:0002650, a Human Phenotype Ontology term): The presence of an abnormal lateral curvature of the spine. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Developmental regression (HP:0002376, a Human Phenotype Ontology term): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Cerebellar hypoplasia (HP:0001321, a Human Phenotype Ontology term): Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time. Evidence: PCS. Frequency: 2/3. (PMID:28777934)
- Feeding difficulties (HP:0011968, a Human Phenotype Ontology term): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Severe global developmental delay (HP:0011344, a Human Phenotype Ontology term): A severe delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Extra-axial cerebrospinal fluid accumulation (HP:0012510, a Human Phenotype Ontology term): An increased amount of cerebrospinal fluid (CSF) in the subarachnoid space. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Epileptic spasm (HP:0011097, a Human Phenotype Ontology term): 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: PCS. Frequency: 1/3. (PMID:28777934)
- Appendicular spasticity (HP:0034353, a Human Phenotype Ontology term): A type of spasticity that affects one or more limbs (arms or legs). Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Hypoplastic optic chiasm (HP:0034311, a Human Phenotype Ontology term): Developmental defect characterized by undergrowth of the optic chiasm. Evidence: PCS. Frequency: 2/3. (PMID:28777934)
- Autosomal recessive inheritance (HP:0000007, 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 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: PCS. (PMID:28777934)
- Optic atrophy (HP:0000648, a Human Phenotype Ontology term): Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy. Evidence: PCS. Frequency: 1/3. (PMID:28777934)
- Myoclonus (HP:0001336, a Human Phenotype Ontology term): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
- Simplified gyral pattern (HP:0009879, a Human Phenotype Ontology term): An abnormality of the cerebral cortex with fewer gyri but with normal cortical thickness. This pattern is usually often associated with congenital microcephaly. Evidence: PCS. Frequency: 3/3. (PMID:28777934)
These phenotypes are associated with the disease early-onset progressive encephalopathy-hearing loss-pons hypoplasia-brain atrophy syndrome (OMIM:617669, an entry in Online Mendelian Inheritance in Man).