- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:833)
- Full cheeks (HP:0000293): Increased prominence or roundness of soft tissues between zygomata and mandible. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
- Deeply set eye (HP:0000490): An eye that is more deeply recessed into the plane of the face than is typical. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
- Ectopia lentis (HP:0001083): Dislocation or malposition of the crystalline lens of the eye. A partial displacement (or dislocation) of the lens is described as a subluxation of the lens, while a complete displacement is termed luxation of the lens. A complete displacement occurs if the lens is completely outside the patellar fossa of the lens, either in the anterior chamber, in the vitreous, or directly on the retina. If the lens is partially displaced but still contained within the lens space, then it is termed subluxation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
- Spastic tetraparesis (HP:0001285): Spastic weakness affecting all four limbs. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- Nausea and vomiting (HP:0002017): Nausea is a commonly encountered symptom that has been defined as an unpleasant painless subjective feeling that one will imminently vomit. Vomiting has been defined as the forceful expulsion of the contents of the stomach, duodenum, or jejunum through the oral cavity. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- Abnormal pattern of respiration (HP:0002793): An anomaly of the rhythm or depth of breathing. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
- Aminoaciduria (HP:0003355): An increased concentration of an amino acid in the urine. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- Hemiplegia/hemiparesis (HP:0004374): Loss of strength in the arm, leg, and sometimes face on one side of the body. Hemiplegia refers to a severe or complete loss of strength, whereas hemiparesis refers to a relatively mild loss of strength. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
- 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:833)
- Prominent forehead (HP:0011220): Forward prominence of the entire forehead, due to protrusion of the frontal bone. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- Thick vermilion border (HP:0012471): Increased width of the skin of vermilion border region of upper lip. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:833)
- 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: Very frequent (HP:0040281). (ORPHA:833)
These phenotypes are associated with the disease Encephalopathy due to sulfite oxidase deficiency (ORPHA:833).