- Hyperphenylalaninemia (HP:0004923): The concentration of L-phenylalanine in the blood circulation is above the upper limit of normal. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1578)
- Abnormal circulating biopterin concentration (HP:0040210): A deviation from the normal concentration of biopterin in the blood circulation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1578)
- Oculogyric crisis (HP:0010553): An acute dystonic reaction with blepharospasm, periorbital twitches, and protracted fixed staring episodes. There may be a maximal upward deviation of the eyes in the sustained fashion. Oculogyric crisis can be triggered by a number of factors including neuroleptic medications. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1578)
- Abnormal circulating neopterin concentration (HP:0040206): Any deviation from the normal concentration of neopterin in the blood circulation. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1578)
- Irritability (HP:0000737): An emotional state characterized by negative feelings of heightened frustration, annoyance, or feeling upset, often triggered by internal factors (e.g., fatigue, hunger, unfulfilled desires) or external factors (e.g., social or environmental challenges). Irritability may be unpredictable, and is accompanied by a lowered threshold for emotional reactivity and observable features (speech, facial expressions, or psychomotor activity). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1578)
- Hypertonia (HP:0001276): A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1578)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1578)
- Hypomagnesemia (HP:0002917): The concentration of magnesium in the blood circulation is below the lower limit of normal. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1578)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1578)
- 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: Occasional (HP:0040283). (ORPHA:1578)
- Parkinsonism (HP:0001300): Characteristic neurologic anomaly resulting from degeneration of dopamine-generating cells in the substantia nigra, a region of the midbrain, characterized clinically by shaking, rigidity, slowness of movement and difficulty with walking and gait. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:1578)
- Maturity-onset diabetes of the young (HP:0004904): The term Maturity-onset diabetes of the young (MODY) was initially used for patients diagnosed with fasting hyperglycemia that could be treated without insulin for more than two years, where the initial diagnosis was made at a young age (under 25 years). Thus, MODY combines characteristics of type 1 diabetes (young age at diagnosis) and type 2 diabetes (less insulin dependence than type 1 diabetes). The term MODY is now most often used to refer to a group of monogenic diseases with these characteristics. Here, the term is used to describe hyperglycemia diagnosed at a young age with no or minor insulin dependency, no evidence of insulin resistance, and lack of evidence of autoimmune destruction of the beta cells. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:1578)
- Cerebral palsy (HP:0100021): Cerebral palsy describes a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to nonprogressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of cerebral palsy are often accompanied by disturbances of sensation, perception, cognition, communication, and behavior, by epilepsy, and by secondary musculoskeletal problems. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:1578)
These phenotypes are associated with the disease Pterin-4 alpha-carbinolamine dehydratase deficiency (ORPHA:1578).