- Optic nerve hypoplasia (HP:0000609): Underdevelopment of the optic nerve. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Optic atrophy (HP:0000648): 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Autistic behavior (HP:0000729): Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- 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:163937)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Rigidity (HP:0002063): Continuous involuntary sustained muscle contraction. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Unsteady gait (HP:0002317). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Proportionate short stature (HP:0003508): A kind of short stature in which different regions of the body are shortened to a comparable extent. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Dyskinesia (HP:0100660): A movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
- Progressive microcephaly (HP:0000253): Progressive microcephaly is diagnosed when the head circumference falls progressively behind age- and gender-dependent norms. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:163937)
- Cerebellar hypoplasia (HP:0001321): Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:163937)
- Moderate intellectual disability (HP:0002342): Moderate intellectual disability (ID) is defined as a type of ID characterized by moderately sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 35-49. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:163937)
- Severe global developmental delay (HP:0011344): A severe delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:163937)
- Hypoplasia of the pons (HP:0012110): Underdevelopment of the pons. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:163937)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Retrognathia (HP:0000278): An abnormality in which the mandible is mislocalised posteriorly. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Hypertelorism (HP:0000316): Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Broad forehead (HP:0000337): Width of the forehead or distance between the frontotemporales is more than two standard deviations above the mean (objective); or apparently increased distance between the two sides of the forehead. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Long philtrum (HP:0000343): Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Macrotia (HP:0000400): Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Sensorineural hearing impairment (HP:0000407): A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Wide nasal bridge (HP:0000431): Increased breadth of the nasal bridge (and with it, the nasal root). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Broad nasal tip (HP:0000455): Increase in width of the nasal tip. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- 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:163937)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Myopia (HP:0000545): An abnormality of refraction characterized by the ability to see objects nearby clearly, while objects in the distance appear blurry. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Dystonia (HP:0001332): 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Cerebral cortical atrophy (HP:0002120): Atrophy of the cortex of the cerebrum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Sleep disturbance (HP:0002360): An abnormal pattern in the quality, quantity, or characteristics of sleep. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Highly arched eyebrow (HP:0002553): Increased height of the central portion of the eyebrow, forming a crescent, semicircular, or inverted U shape. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Short nose (HP:0003196): Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Feeding difficulties in infancy (HP:0008872): Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Floppy infant (HP:0008947): Floppiness/hypotonia is defined as reduced resistance to passive movement of joints. Physical examination of floppy/hypotonic infants shows head lag, lack of shoulder and elbow muscle contraction on traction response, inability to tighten the shoulder girdle muscles (or slipping through) when held under the axillae, scarf sign (when the arm is pulled to the opposite side, the arm wraps around the neck with the elbow crossing midline), hyperdorsiflexion of the feet, easy apposition of the thumb against the forearm, feet touching the cheek with ease and without discomfort, frog leg position, and inverted U sign on ventral suspension (head, arms, and legs hanging down without elbow or knee flexion and the trunk rounded in a dome shape). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Epileptic spasm (HP:0011097): 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Stereotypical hand wringing (HP:0012171): Habitual clasping and wringing of the hands in the middle of the body, similar to a hand-washing movement. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- 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: Frequent (HP:0040282). (ORPHA:163937)
- Appendicular spasticity (HP:0034353): A type of spasticity that affects one or more limbs (arms or legs). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:163937)
- Optic disc pallor (HP:0000543): A pale yellow discoloration of the optic disc (the area of the optic nerve head in the retina). The optic disc normally has a pinkish hue with a central yellowish depression. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:163937)
These phenotypes are associated with the disease X-linked intellectual disability, Najm type (ORPHA:163937).