- Upgaze palsy (HP:0025331): A limitation of the ability to direct one's gaze above the horizontal meridian. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Tip-toe gait (HP:0030051): An abnormal gait pattern characterized by the failure of the heel to contact the floor at the onset of stance during gait. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Neck hypertonia (HP:0031867): Increased passive stiffness or tightness of the neck musculature. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Nasogastric tube feeding (HP:0040288): The condition of inability to eat normally treated by placement of a thin tube through the nose into the stomach that is then used to carry food. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Thin eyebrow (HP:0045074): Decreased diameter of eyebrow hairs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Abnormality of movement (HP:0100022): An abnormality of movement with a neurological basis characterized by changes in coordination and speed of voluntary movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Atypical behavior (HP:0000708): Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Short attention span (HP:0000736): Reduced attention span characterized by distractibility and impulsivity. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- 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:2203)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Hyperammonemia (HP:0001987): An increased concentration of ammonia in the blood. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Hyperlysinemia (HP:0002161): The concentration of lysine in the blood circulation is above the upper limit of normal. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Cystinuria (HP:0003131): An increased concentration of cystine in the urine. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Argininuria (HP:0003268): A increased concentration of arginine in the urine. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Hyperlysinuria (HP:0003297): An increased concentration of lysine in the urine. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Short stature (HP:0004322): A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- 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:2203)
- EEG with spike-wave complexes (HP:0010850): Complexes of spikes (<70 ms) and sharp waves (70-200 ms), which are sharp transient waves that have a strong association with epilepsy, in cerebral electrical activity recorded along the scalp by electroencephalography (EEG). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Abnormal circulating enzyme concentration or activity (HP:0012379): Concentration or activity of an enzyme is above or below the limits of normal in the blood circulation. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Decreased urine alpha-ketoglutarate concentration (HP:0012403): A lower than normal concentration of 2-oxoglutaric acid in the urine. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- 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: Frequent (HP:0040282). (ORPHA:2203)
- Hypoornithinemia (HP:0500163): An abnormal decrease in ornithine in the blood. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Decreased CSF arginine concentration (HP:0500204): Abnormally decreased levels of arginine in cerebrospinal fluid. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Increased CSF lysine concentration (HP:0500208): Abnormally increased levels of lysine in cerebrospinal fluid. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- Abnormal CSF ornithine concentration (HP:0500243): Any deviation from the normal concentration of ornithine in the cerebrospinal fluid. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2203)
- High palate (HP:0000218): Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Smooth philtrum (HP:0000319): Flat skin surface, with no ridge formation in the central region of the upper lip between the nasal base and upper vermilion border. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Depressed nasal ridge (HP:0000457): Lack of prominence of the nose resulting from a posteriorly-placed nasal ridge. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- 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: Occasional (HP:0040283). (ORPHA:2203)
- Hypotelorism (HP:0000601): Interpupillary distance less than 2 SD below the mean (alternatively, the appearance of an decreased interpupillary distance or closely spaced eyes). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Hyperactivity (HP:0000752): Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Spastic diplegia (HP:0001264): Spasticity (neuromuscular hypertonia) primarily in the muscles of the legs, hips, and pelvis. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Spastic tetraparesis (HP:0001285): Spastic weakness affecting all four limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Dysmetria (HP:0001310): A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Brisk reflexes (HP:0001348): Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Craniosynostosis (HP:0001363): Craniosynostosis refers to the premature closure of the cranial sutures. Primary craniosynostosis refers to the closure of one or more sutures due to abnormalities in skull development, and secondary craniosynostosis results from failure of brain growth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- 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:2203)
- Abnormal facial shape (HP:0001999): An abnormal morphology (form) of the face or its components. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Vomiting (HP:0002013): Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Gastroesophageal reflux (HP:0002020): A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Poor suck (HP:0002033): An inadequate sucking reflex, resulting in the difficult of newborns to be breast-fed. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Opisthotonus (HP:0002179): Opisthotonus is defined as a dramatic abnormal posture due to spastic contraction of the extensor muscles of the neck, trunk, and lower extremities that produces a severe backward arching from neck to heel. In most cases, the trunk is elevated off the ground by a few inches. It is usually sudden in onset and can be sustained or repetitive. It can be considered a variant of decerebrate posturing involving a hyperextension of the neck, back, and limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Incoordination (HP:0002311): A deficit in coordination of muscle movements. Coordination is defined as the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Clumsiness (HP:0002312): Lack of physical coordination resulting in an abnormal tendency to drop items or bump into objects. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Pulmonary artery hypoplasia (HP:0004971): Underdevelopment of the pulmonary artery. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Recurrent pneumonia (HP:0006532): An increased susceptibility to pneumonia as manifested by a history of recurrent episodes of pneumonia. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Borderline intellectual disability (HP:0006889): Borderline intellectual disability is defined as an intelligence quotient (IQ) in the range of 70-85. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Hypoplastic helices (HP:0008589): Underdevelopment of the helix, i.e., of the outer rim of the pinna. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Hypoplasia of the antihelix (HP:0009739): Developmental hypoplasia of the antihelix. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Simple febrile seizure (HP:0011171): A short generalized seizure, of a duration of <15 min, not recurring within 24 h, occurring during a febrile episode not caused by an acute disease of the nervous system intracranial infection or severe metabolic disturbance. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Mild global developmental delay (HP:0011342): A mild delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2203)
These phenotypes are associated with the disease Hyperlysinemia (ORPHA:2203).