- Cerebral hypoplasia (HP:0006872): Underdevelopment of the cerebrum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Hypoglycinemia (HP:0012277): An abnormally reduced concentration of glycine in the blood. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79351)
- Hyposerinemia (HP:0012279): Reduced concentration of serine in the blood. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79351)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- Esotropia (HP:0000565): A form of strabismus with one or both eyes turned inward ('crossed') to a relatively severe degree, usually defined as 10 diopters or more. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- 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: Frequent (HP:0040282). (ORPHA:79351)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- 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: Frequent (HP:0040282). (ORPHA:79351)
- 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:79351)
- Cerebral hypomyelination (HP:0006808): Reduced amount of myelin in the nervous system resulting from defective myelinogenesis in the white matter of the central nervous system. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- Developmental stagnation (HP:0007281): A cessation of the development of a child in the areas of motor skills, speech and language, cognitive skills, and social and/or emotional skills. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- 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:79351)
- 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: Frequent (HP:0040282). (ORPHA:79351)
- Primary microcephaly (HP:0011451): Head circumference below 2 standard deviations below the mean for age and gender at birth. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- 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: Frequent (HP:0040282). (ORPHA:79351)
- Delayed myelination (HP:0012448): Delayed myelination. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- Cerebral white matter atrophy (HP:0012762): The presence of atrophy (wasting) of the cerebral white matter. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79351)
- Inguinal hernia (HP:0000023): Protrusion of the contents of the abdominal cavity through the inguinal canal. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Hypogonadism (HP:0000135): A decreased functionality of the gonad. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Developmental cataract (HP:0000519): A cataract that occurs congenitally as the result of a developmental defect, in contrast to the majority of cataracts that occur in adulthood as the result of degenerative changes of the lens. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- 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: Occasional (HP:0040283). (ORPHA:79351)
- 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:79351)
- Adducted thumb (HP:0001181): In the resting position, the tip of the thumb is on, or near, the palm, close to the base of the fourth or fifth finger. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- 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:79351)
- Umbilical hernia (HP:0001537): Protrusion of abdominal contents through a defect in the abdominal wall musculature around the umbilicus. Skin and subcutaneous tissue overlie the defect. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Megaloblastic anemia (HP:0001889): Anemia characterized by the presence of erythroblasts that are larger than normal (megaloblasts). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Abnormal facial shape (HP:0001999): An abnormal morphology (form) of the face or its components. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- 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:79351)
- Bilateral tonic-clonic seizure (HP:0002069): A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Generalized non-motor (absence) seizure (HP:0002121): A generalized non-motor (absence) seizure is a type of a type of dialeptic seizure that is of electrographically generalized onset. It is a generalized seizure characterized by an interruption of activities, a blank stare, and usually the person will be unresponsive when spoken to. Any ictal motor phenomena are minor in comparison to these non-motor features. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Generalized myoclonic seizure (HP:0002123): A generalized myoclonic seizure is a type of generalized motor seizure characterized by bilateral, 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:79351)
- Athetosis (HP:0002305): A slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture. Athetosis involves continuous smooth movements that appear random and are not composed of recognizable sub-movements or movement fragments. In contrast to chorea, in athetosis, the same regions of the body are repeatedly involved. Athetosis may worsen with attempts at movement of posture, but athetosis can also occur at rest. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Spastic tetraplegia (HP:0002510): Spastic paralysis affecting all four limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Abnormal cortical gyration (HP:0002536): An abnormality of the gyri (i.e., the ridges) of the cerebral cortex of the brain. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Cerebral hypoplasia (HP:0006872): Underdevelopment of the cerebrum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Generalized ichthyosis (HP:0007503). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Abnormality of hair texture (HP:0010719): An abnormality of the texture of the hair. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Atonic seizure (HP:0010819): Atonic seizure is a type of motor seizure characterized by a sudden loss or diminution of muscle tone without apparent preceding myoclonic or tonic event lasting about 1 to 2 seconds, involving head, trunk, jaw, or limb musculature. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Focal emotional seizure with laughing (HP:0010821): Focal emotional seizure with laughing (gelastic) is characterized by bursts of laughter or giggling, usually without appropriate related emotion of happiness, and described as 'mirthless'. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Moderate global developmental delay (HP:0011343): A moderate delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Inappropriate crying (HP:0030215): Uncontrolled episodes of crying occur without any apparent motivating stimuli. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- Esophagitis (HP:0100633): Inflammation of the esophagus. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79351)
- 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:79351)
These phenotypes are associated with the disease 3-phosphoglycerate dehydrogenase deficiency, infantile/juvenile form (ORPHA:79351).