- Progressive (HP:0003676): 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:28503735)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: PCS. (PMID:28503735)
- 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: PCS. Frequency: 5/6. (PMID:28503735)
- Antenatal onset (HP:0030674): Onset prior to birth. Evidence: PCS. Frequency: 1/6. (PMID:28503735)
- 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: 6/6. (PMID:28503735)
- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: PCS. Frequency: 3/6. (PMID:28503735)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 3/6. (PMID:28503735)
- Focal tonic seizure (HP:0011167): A type of focal motor seizure characterized by sustained increase in muscle contraction, lasting a few seconds to minutes. Evidence: PCS. Frequency: 1/6. (PMID:28503735)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 7/11. (PMID:28503735)
- Cerebral hypoplasia (HP:0006872): Underdevelopment of the cerebrum. Evidence: PCS. (PMID:28503735)
- Neonatal onset (HP:0003623): Onset of signs or symptoms of disease within the first 28 days of life. Evidence: PCS. Frequency: 2/6. (PMID:28503735)
- Kyphoscoliosis (HP:0002751): An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane. Evidence: PCS. Frequency: 1/6. (PMID:28503735)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 2/6. (PMID:28503735)
- Spastic tetraplegia (HP:0002510): Spastic paralysis affecting all four limbs. Evidence: PCS. Frequency: 5/6. (PMID:28503735)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 4/12. (PMID:28503735)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: PCS. (PMID:28503735)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: PCS. Frequency: 5/5. (PMID:28503735)
- Respiratory distress (HP:0002098): Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea. Evidence: PCS. Frequency: 1/6. (PMID:28503735)
- 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: 9/12. (PMID:28503735)
- Joint contracture (HP:0034392): A limitation in the passive range of motion of a joint resulting from loss of elasticity in the periarticular tissues owing to structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules or skin. A contracture prevents movement of the associated body part. Evidence: PCS. Frequency: 5/6. (PMID:28503735)
- Reduced cerebral white matter volume (HP:0034295): An abnormally low volume of the white matter of the brain. Evidence: PCS. Frequency: 5/5. (PMID:28503735)
- 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: PCS. (PMID:28503735)
- Visual impairment (HP:0000505): Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery. Evidence: PCS. (PMID:28503735)
- Spastic paraplegia (HP:0001258): Complete loss of the ability to move the lower limbs accompanied by spasticity of the lower limbs. Evidence: PCS. Frequency: 6/6. (PMID:28503735)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: PCS. Frequency: 1/6. (PMID:28503735)
These phenotypes are associated with the disease neurodevelopmental disorder with spastic quadriplegia and brain abnormalities with or without seizures (OMIM:617977).