- 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: PCS. Frequency: 2/6. (PMID:36823193)
- Epicanthus (HP:0000286): A fold of skin starting above the medial aspect of the upper eyelid and arching downward to cover, pass in front of and lateral to the medial canthus. Evidence: PCS. Frequency: 3/7. (PMID:36823193)
- Exaggerated startle response (HP:0002267): An exaggerated startle reaction in response to a sudden unexpected visual or acoustic stimulus, or a quick movement near the face. Evidence: PCS. Frequency: 1/7. (PMID:36823193)
- 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: PCS. Frequency: 2/5. (PMID:36823193)
- Gait ataxia (HP:0002066): A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall. Evidence: PCS. Frequency: 2/7. (PMID:36823193)
- Elevated circulating alkaline phosphatase concentration (HP:0003155): Abnormally increased serum levels of alkaline phosphatase activity. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Elevated brain lactate level by MRS (HP:0012707): An increase in the level of lactate in the brain identified by magnetic resonance spectroscopy (MRS). Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- 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: PCS. Frequency: 2/2. (PMID:36823193)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 1/7. (PMID:36823193)
- Low insertion of columella (HP:0010763): Insertion of the posterior columella below the nasal base. Evidence: PCS. Frequency: 3/7. (PMID:36823193)
- Appendicular hypotonia (HP:0012389): Muscular hypotonia of one or more limbs. Evidence: PCS. Frequency: 1/7. (PMID:36823193)
- Thin corpus callosum (HP:0033725): An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration). Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 3/6. (PMID:36823193)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 5/7. (PMID:36823193)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: PCS. Frequency: 2/5. (PMID:36823193)
- Ophthalmoparesis (HP:0000597): Ophthalmoplegia is a paralysis or weakness of one or more of the muscles that control eye movement. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: PCS. Frequency: 5/6. (PMID:36823193)
- Hyperalaninemia (HP:0003348): An increased concentration of alanine in the blood. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Neonatal onset (HP:0003623): Onset of signs or symptoms of disease within the first 28 days of life. Evidence: PCS. Frequency: 1/7. (PMID:36823193)
- Visual loss (HP:0000572): Loss of visual acuity (implying that vision was better at a certain time point in life). Otherwise the term reduced visual acuity should be used (or a subclass of that). Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Ragged-red muscle fibers (HP:0003200): An abnormal appearance of muscle fibers observed on muscle biopsy. Ragged red fibers can be visualized with Gomori trichrome staining as irregular and intensely red subsarcolemmal zones, whereas the normal myofibrils are green. The margins of affect fibers appear red and ragged. The ragged-red is due to the accumulation of abnormal mitochondria below the plasma membrane of the muscle fiber, leading to the appearance of a red rim and speckled sarcoplasm. Evidence: PCS. Frequency: 2/3. (PMID:36823193)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: PCS. Frequency: 2/7. (PMID:36823193)
- 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: PCS. Frequency: 7/7. (PMID:36823193)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Decreased activity of mitochondrial complex I (HP:0011923): A reduction in the activity of the mitochondrial respiratory chain complex I, which is part of the electron transport chain in mitochondria. Evidence: PCS. Frequency: 3/3. (PMID:36823193)
- Appendicular spasticity (HP:0034353): A type of spasticity that affects one or more limbs (arms or legs). Evidence: PCS. Frequency: 2/6. (PMID:36823193)
- Visual fixation instability (HP:0025405): A deficit in the ability to fixate eye movements in order to stabilize images on the retina. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Optic atrophy (HP:0000648): Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy. Evidence: PCS. Frequency: 2/6. (PMID:36823193)
- 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: PCS. Frequency: 2/7. (PMID:36823193)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:36823193)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. Frequency: 1/6. (PMID:36823193)
- Respiratory failure requiring assisted ventilation (HP:0004887): A state of respiratory distress that requires a life saving intervention in the form of gaining airway access and instituting positive pressure ventilation. Evidence: PCS. Frequency: 1/7. (PMID:36823193)
- 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: PCS. Frequency: 1/1. (PMID:36823193)
- Epilepsia partialis continua (HP:0012847): Epilepsia partialis continua (also called Kojevnikov's or Kozhevnikov's epilepsia) is a type of focal motor status epilepticus characterized by repeated stereotyped simple motor manifestations such as jerks, typically of a limb or the face, recurring every few seconds or minutes for extended periods (days or years). Evidence: PCS. Frequency: 1/6. (PMID:36823193)
- Reduced visual acuity (HP:0007663). Evidence: PCS. Frequency: 1/5. (PMID:36823193)
- Hypoglycemia (HP:0001943): A decreased concentration of glucose in the blood. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Lacticaciduria (HP:0003648): An increased concentration of lactic acid in the urine. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Hyperprolinemia (HP:0008358): The concentration of proline in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- CNS demyelination (HP:0007305): A loss of myelin from nerve fibers in the central nervous system. Evidence: PCS. Frequency: 2/2. (PMID:36823193)
- EMG: decremental response of compound muscle action potential to repetitive nerve stimulation (HP:0003403): A compound muscle action potential (CMAP) is a type of electromyography (EMG). CMAP refers to a group of almost simultaneous action potentials from several muscle fibers in the same area evoked by stimulation of the supplying motor nerve and are recorded as one multipeaked summated action potential. This abnormality refers to a greater than normal decrease in the amplitude during the course of the investigation. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 5/7. (PMID:36823193)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: PCS. Frequency: 4/7. (PMID:36823193)
- Vomiting (HP:0002013): Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Gliosis (HP:0002171): Gliosis is the focal proliferation of glial cells in the central nervous system. Evidence: PCS. Frequency: 1/1. (PMID:36823193)
- Ptosis (HP:0000508): The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective). Evidence: PCS. Frequency: 3/6. (PMID:36823193)
- Prominent nasal bridge (HP:0000426): Anterior positioning of the nasal root in comparison to the usual positioning for age. Evidence: PCS. Frequency: 1/7. (PMID:36823193)
- Peripheral neuropathy (HP:0009830): Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course. Evidence: PCS. Frequency: 0/7. (PMID:36823193)
- 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: PCS. Frequency: 2/2. (PMID:36823193)
These phenotypes are associated with the disease combined oxidative phosphorylation deficiency 58 (OMIM:620451).