- Visual impairment (HP:0000505): Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:254930)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:254930)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:254930)
- Ophthalmoplegia (HP:0000602): Paralysis of one or more extraocular muscles that are responsible for eye movements. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Visual field defect (HP:0001123). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- 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:254930)
- Pes cavus (HP:0001761): An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Spastic paraparesis (HP:0002313): Partial loss of the ability to move the lower limbs accompanied by spasticity of the lower limbs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Lower limb hyperreflexia (HP:0002395): Increased intensity of the a reflex in the leg. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Distal sensory impairment (HP:0002936): An abnormal reduction in sensation in the distal portions of the extremities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Peripheral axonal neuropathy (HP:0003477): An abnormality characterized by disruption of the normal functioning of peripheral axons. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Abnormal pyramidal sign (HP:0007256): Functional neurological abnormalities related to dysfunction of the pyramidal tract. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Lower limb muscle weakness (HP:0007340): Weakness of the muscles of the legs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Impaired tandem gait (HP:0031629): Reduced ability to walk in a straight line while placing the feet heel to toe. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- Cognitive impairment (HP:0100543): Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:254930)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- 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:254930)
- 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: Occasional (HP:0040283). (ORPHA:254930)
- Dysarthria (HP:0001260): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Bulbar palsy (HP:0001283): Bulbar weakness (or bulbar palsy) refers to bilateral impairment of function of the lower cranial nerves IX, X, XI and XII, which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain-stem. Bulbar weakness is often associated with difficulty in chewing, weakness of the facial muscles, dysarthria, palatal weakness and regurgitation of fluids, dysphagia, and dysphonia. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Facial diplegia (HP:0001349): Facial diplegia refers to bilateral facial palsy (bilateral facial palsy is much rarer than unilateral facial palsy). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Abnormal cerebral white matter morphology (HP:0002500): An abnormality of the cerebral white matter. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Paralytic ileus (HP:0002590). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Thoracic scoliosis (HP:0002943). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Decreased number of peripheral myelinated nerve fibers (HP:0003380): A loss of myelinated nerve fibers in the peripheral nervous system (in general, this finding can be observed on nerve biopsy). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Upper limb muscle weakness (HP:0003484): Weakness of the muscles of the arms. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Impaired mastication (HP:0005216): An abnormal reduction in the ability to masticate (chew), i.e., in the ability to crush and ground food in preparation for swallowing. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Dyschromatopsia (HP:0007641): A form of colorblindness in which only two of the three fundamental colors can be distinguished due to a lack of one of the retinal cone pigments. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Floppy infant (HP:0008947): Floppiness/hypotonia is defined as reduced resistance to passive movement of joints. Physical examination of floppy/hypotonic infants shows head lag, lack of shoulder and elbow muscle contraction on traction response, inability to tighten the shoulder girdle muscles (or slipping through) when held under the axillae, scarf sign (when the arm is pulled to the opposite side, the arm wraps around the neck with the elbow crossing midline), hyperdorsiflexion of the feet, easy apposition of the thumb against the forearm, feet touching the cheek with ease and without discomfort, frog leg position, and inverted U sign on ventral suspension (head, arms, and legs hanging down without elbow or knee flexion and the trunk rounded in a dome shape). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Gastrostomy tube feeding in infancy (HP:0011471): Feeding problem necessitating gastrostomy tube feeding. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Abnormal thalamic MRI signal intensity (HP:0012696): A deviation from normal signal on magnetic resonance imaging (MRI) of the thalamus. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Abnormal brainstem MRI signal intensity (HP:0012747): A deviation from normal signal on magnetic resonance imaging (MRI) of the brainstem. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Exodeviation (HP:0020049): A manifest or latent ocular deviation in which one or both eyes tends to deviate temporally. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
- Oral-pharyngeal dysphagia (HP:0200136). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:254930)
These phenotypes are associated with the disease Combined oxidative phosphorylation defect type 7 (ORPHA:254930).