- Profound intellectual disability (HP:0002187): Profound intellectual disability (ID) is defined as a type of ID characterized by profoundly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) below 20. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:468699)
- Severe muscular hypotonia (HP:0006829): A severe degree of muscular hypotonia characterized by markedly reduced muscle tone. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:468699)
- Abnormal circulating zinc concentration (HP:0008277): Any deviation from the normal concentration of zinc in the blood circulation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:468699)
- Type II transferrin isoform profile (HP:0012301): Abnormal transferrin isoform profile consistent with a type II congenital disorder of glycosylation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:468699)
- Profound global developmental delay (HP:0012736): A profound 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:468699)
- Hypomanganesemia (HP:0032098): The concentration of manganese cation in the blood circulation is below the lower limit of normal. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:468699)
- 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:468699)
- 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:468699)
- Cerebellar atrophy (HP:0001272): Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:468699)
- Failure to thrive in infancy (HP:0001531). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:468699)
- Cerebral cortical atrophy (HP:0002120): Atrophy of the cortex of the cerebrum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:468699)
- Poor head control (HP:0002421): Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:468699)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:468699)
- 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:468699)
- Visual fixation instability (HP:0025405): A deficit in the ability to fixate eye movements in order to stabilize images on the retina. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:468699)
- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Low-set ears (HP:0000369): Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Astigmatism (HP:0000483): A type of refraction error associated with abnormal curvatures on the anterior and/or posterior surface of the cornea. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Hypermetropia (HP:0000540): An abnormality of refraction characterized by the ability to see objects in the distance clearly, while objects nearby appear blurry. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Osteopenia (HP:0000938): Osteopenia is a term to define bone density that is not normal but also not as low as osteoporosis. By definition from the World Health Organization osteopenia is defined by bone densitometry as a T score -1 to -2.5. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- 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: Occasional (HP:0040283). (ORPHA:468699)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- 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:468699)
- Abnormality of the liver (HP:0001392): An abnormality of the liver. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Poor speech (HP:0002465). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Increased CSF lactate (HP:0002490): Increased concentration of lactate in the cerebrospinal fluid. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Hypsarrhythmia (HP:0002521): Hypsarrhythmia is abnormal interictal high amplitude waves and a background of irregular spikes. There is continuous (during wakefulness), high-amplitude (>200 Hz), generalized polymorphic slowing with no organized background and multifocal spikes demonstrated by electroencephalography (EEG). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Recurrent infections (HP:0002719): Increased susceptibility to infections as manifested by repeated bouts of infection. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Sudden episodic apnea (HP:0002882): Recurrent bouts of sudden, severe apnea that may be life-threatening. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Decreased activity of the pyruvate dehydrogenase complex (HP:0002928). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Elbow flexion contracture (HP:0002987): An elbow contracture that limits the ability of the elbow joint to be extended (straightened), meaning that the elbow is fixed in an flexed (bent) position. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Knee flexion contracture (HP:0006380): A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Decreased mitochondrial complex III activity in liver tissue (HP:0006558): Decreased activity of complex III of the mitochondrion in the liver. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Decreased activity of mitochondrial complex II (HP:0008314): A reduction in the activity of the mitochondrial respiratory chain complex II, which is part of the electron transport chain in mitochondria. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Decreased activity of mitochondrial complex IV (HP:0008347): A reduction in the activity of the mitochondrial respiratory chain complex IV, which is part of the electron transport chain in mitochondria. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Disproportionate short-limb short stature (HP:0008873): A type of disproportionate short stature characterized by a short limbs but an average-sized trunk. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Limb undergrowth (HP:0009826): Limb shortening because of underdevelopment of one or more bones of the extremities. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Cutaneous syndactyly of toes (HP:0010621): A soft tissue continuity in the anteroposterior axis between adjacent foot digits that involves at least half of the proximodistal length of one of the two involved digits; or, a soft tissue continuity in the A/P axis between two digits of the foot that does not meet the prior objective criteria. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
- Flat face (HP:0012368): Absence of concavity or convexity of the face when viewed in profile. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:468699)
These phenotypes are associated with the disease SLC39A8-CDG (ORPHA:468699).