- 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. (PMID:29215095)
- 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:29215095)
- Inability to walk (HP:0002540, a Human Phenotype Ontology term): Incapability to ambulate. Evidence: PCS. Frequency: 4/4. (PMID:29215095)
- Anteverted nares (HP:0000463, a Human Phenotype Ontology term): Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip). Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Cerebellar atrophy (HP:0001272, a Human Phenotype Ontology term): Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event. Evidence: PCS. (PMID:29215095)
- Flexion contracture (HP:0001371, a Human Phenotype Ontology term): 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: PCS. Frequency: 2/4. (PMID:29215095)
- 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: 4/4. (PMID:29215095)
- Profound intellectual disability (HP:0002187, a Human Phenotype Ontology term): 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. (PMID:29215095)
- 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. (PMID:29215095)
- Thick vermilion border (HP:0012471, a Human Phenotype Ontology term): Increased width of the skin of vermilion border region of upper lip. Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Low hanging columella (HP:0009765, a Human Phenotype Ontology term): Columella extending inferior to the level of the nasal base, when viewed from the side. Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Death in infancy (HP:0001522, a Human Phenotype Ontology term): Death within the first 24 months of life. Evidence: PCS. Frequency: 1/4. (PMID:29215095)
- Gingival overgrowth (HP:0000212, a Human Phenotype Ontology term): Hyperplasia of the gingiva (that is, a thickening of the soft tissue overlying the alveolar ridge. The degree of thickening ranges from involvement of the interdental papillae alone to gingival overgrowth covering the entire tooth crown. Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Leukodystrophy (HP:0002415, a Human Phenotype Ontology term): Leukodystrophy refers to deterioration of white matter of the brain resulting from degeneration of myelin sheaths in the CNS. Their basic defect is directly related to the synthesis and maintenance of myelin membranes. Symmetric white matter involvement at MRI is a typical finding in patients with leukodystrophies. Evidence: PCS. (PMID:29215095)
- Hirsutism (HP:0001007, a Human Phenotype Ontology term): Abnormally increased hair growth referring to a male pattern of body hair (androgenic hair). Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Hyperreflexia (HP:0001347, a Human Phenotype Ontology term): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: PCS. Frequency: 4/4. (PMID:29215095)
- Kyphoscoliosis (HP:0002751, a Human Phenotype Ontology term): An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane. Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Cerebral atrophy (HP:0002059, a Human Phenotype Ontology term): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: PCS. (PMID:29215095)
- Microcephaly (HP:0000252, a Human Phenotype Ontology term): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 4/4. (PMID:29215095)
- Absent speech (HP:0001344, a Human Phenotype Ontology term): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 4/4. (PMID:29215095)
- Hypoplasia of the corpus callosum (HP:0002079, a Human Phenotype Ontology term): Underdevelopment of the corpus callosum. Evidence: PCS. (PMID:29215095)
- 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: 4/4. (PMID:29215095)
- Profound global developmental delay (HP:0012736, a Human Phenotype Ontology term): A profound delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: PCS. Frequency: 4/4. (PMID:29215095)
- 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:29215095)
- Growth delay (HP:0001510, a Human Phenotype Ontology term): A deficiency or slowing down of growth pre- and postnatally. Evidence: PCS. Frequency: 4/4. (PMID:29215095)
- Mandibular prognathia (HP:0000303, a Human Phenotype Ontology term): Abnormal prominence of the chin related to increased length of the mandible. Evidence: PCS. Frequency: 2/4. (PMID:29215095)
- Widely spaced teeth (HP:0000687, a Human Phenotype Ontology term): Increased spaces (diastemata) between most of the teeth in the same dental arch. Evidence: PCS. Frequency: 2/4. (PMID:29215095)
These phenotypes are associated with the disease leukodystrophy, hypomyelinating, 17 (OMIM:618006, an entry in Online Mendelian Inheritance in Man).