- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Abnormal basal ganglia morphology (HP:0002134): Abnormality of the basal ganglia. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Orofacial dyskinesia (HP:0002310). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Hip contracture (HP:0003273): Lack of full passive range of motion (restrictions in flexion, extension, or other movements) of the hip joint resulting from structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules and/or skin. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Subsarcolemmal accumulations of abnormally shaped mitochondria (HP:0003548): An abnormally increased number of mitochondria in the cytoplasma adjacent to the sarcolemma (muscle cell membrane), whereby the mitochondria also possess an abnormal morphology. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Type 2 muscle fiber atrophy (HP:0003554): Atrophy (wasting) affecting primary type 2 muscle fibers. This feature in general can only be observed on muscle biopsy. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Type 1 muscle fiber predominance (HP:0003803): An abnormal predominance of type I muscle fibers (in general, this feature can only be observed on muscle biopsy). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Ankle flexion contracture (HP:0006466). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Lower limb hypertonia (HP:0006895). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Gastrostomy tube feeding in infancy (HP:0011471): Feeding problem necessitating gastrostomy tube feeding. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- 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:319514)
- Elevated CSF neopterin level (HP:0040204): Increased concentration of neopterin in the cerebrospinal fluid (CSF). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Increased circulating lactate concentration (HP:0002151): Abnormally increased level of blood lactate (2-hydroxypropanoic acid). Lactate is produced from pyruvate by lactate dehydrogenase during normal metabolism. The terms lactate and lactic acid are often used interchangeably but lactate (the component measured in blood) is strictly a weak base whereas lactic acid is the corresponding acid. Lactic acidosis is often used clinically to describe elevated lactate but should be reserved for cases where there is a corresponding acidosis (pH below 7.35). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:319514)
- Mitochondrial respiratory chain defects (HP:0200125). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:319514)
- Sensorineural hearing impairment (HP:0000407): A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Choreoathetosis (HP:0001266): Involuntary movements characterized by both athetosis (inability to sustain muscles in a fixed position) and chorea (widespread jerky arrhythmic movements). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- 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:319514)
- Limb dystonia (HP:0002451): A type of dystonia (abnormally increased muscular tone causing fixed abnormal postures) that affects muscles of the limbs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Increased CSF lactate (HP:0002490): Increased concentration of lactate in the cerebrospinal fluid. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Profound static encephalopathy (HP:0007069). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Abnormal corpus striatum morphology (HP:0010994): Abnormality of the striatum, which is the largest nucleus of the basal ganglia, comprising the caudate, putamen and ventral striatum, including the nucleus accumbens. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Delayed myelination (HP:0012448): Delayed myelination. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:319514)
- Abnormality of eye movement (HP:0000496): An abnormality in voluntary or involuntary eye movements or their control. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- 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:319514)
- Decreased nerve conduction velocity (HP:0000762): A reduction in the speed at which electrical signals propagate along the axon of a neuron. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Sensory neuropathy (HP:0000763): Peripheral neuropathy affecting the sensory nerves. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Abnormal corpus callosum morphology (HP:0001273): Abnormality of the corpus callosum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:319514)
- 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:319514)
These phenotypes are associated with the disease Combined oxidative phosphorylation defect type 13 (ORPHA:319514).