- Pachygyria (HP:0001302): Pachygyria is a malformation of cortical development with abnormally wide gyri with sulci 1,5-3 cm apart and abnormally thick cortex measuring more than 5 mm (radiological definition). See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Aplasia/Hypoplasia of the cerebellum (HP:0007360). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Severe intellectual disability (HP:0010864): Severe intellectual disability (ID) is defined as a type of ID characterized by severely sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 20-34. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Neurodevelopmental delay (HP:0012758): Neurodevelopmental delay (NDD) refers to delays in the maturation of the brain and central nervous system; infants and young children with NDD may experience delays in the development of one or more skills including gross motor abilities, fine-motor coordination, language abilities and ability to solve increasingly complex problems. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Abnormal hippocampus morphology (HP:0025100): Any structural anomaly of the hippocampus,. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Abnormality of the anterior commissure (HP:0030301): An anomaly of the anterior commissure, a bundle of nerve fibers that connect the two cerebral hemispheres across the midline. The anterior commissure plays a role in pain sensation and contains decussating fibers from the olfactory tracts. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:572013)
- Strabismus (HP:0000486): A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:572013)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:572013)
- Involuntary movements (HP:0004305): Involuntary contractions of muscle leading to involuntary movements of extremities, neck, trunk, or face. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:572013)
- Thin corpus callosum (HP:0033725): An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:572013)
- Neurogenic bladder (HP:0000011): 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- Facial asymmetry (HP:0000324): An abnormal difference between the left and right sides of the face. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- Optic nerve hypoplasia (HP:0000609): Underdevelopment of the optic nerve. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- Motor stereotypy (HP:0000733): Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- Hip dislocation (HP:0002827): Displacement of the femur from its normal location in the hip joint. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- Infantile spasms (HP:0012469): Infantile spasms represent a subset of "epileptic spasms". Infantile Spasms are epileptic spasms starting in the first year of life (infancy). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- Myoclonic seizure (HP:0032794): A myoclonic seizure is a type of motor seizure characterized by sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:572013)
These phenotypes are associated with the disease Posterior-predominant lissencephaly-broad flat pons and medulla-midline crossing defects syndrome (ORPHA:572013).