- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Rod-cone dystrophy (HP:0000510): An inherited retinal disease subtype in which the rod photoreceptors appear to be more severely affected than the cone photoreceptors. Typical presentation is with nyctalopia (due to rod dysfunction) followed by loss of mid-peripheral field of vision, which gradually extends and leaves many patients with a small central island of vision due to the preservation of macular cones. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Optic disc pallor (HP:0000543): A pale yellow discoloration of the optic disc (the area of the optic nerve head in the retina). The optic disc normally has a pinkish hue with a central yellowish depression. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Blindness (HP:0000618): Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- 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:644)
- Dementia (HP:0000726): A loss of global cognitive ability of sufficient amount to interfere with normal social or occupational function. Dementia represents a loss of previously present cognitive abilities, generally in adults, and can affect memory, thinking, language, judgment, and behavior. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- 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: Frequent (HP:0040282). (ORPHA:644)
- Sensory neuropathy (HP:0000763): Peripheral neuropathy affecting the sensory nerves. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Constriction of peripheral visual field (HP:0001133): An absolute or relative decrease in retinal sensitivity extending from edge (periphery) of the visual field in a concentric pattern. The visual field is the area that is perceived simultaneously by a fixating eye. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Retinal arteriolar tortuosity (HP:0001136): The presence of an increased number of twists and turns of the retinal arterioles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- 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:644)
- 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: Frequent (HP:0040282). (ORPHA:644)
- 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:644)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Cerebral cortical atrophy (HP:0002120): Atrophy of the cortex of the cerebrum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Headache (HP:0002315): Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Muscle spasm (HP:0003394): Sudden and involuntary contractions of one or more muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Babinski sign (HP:0003487): Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Proximal muscle weakness (HP:0003701): A lack of strength of the proximal muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Myoclonic spasms (HP:0003739). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- 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:644)
- Corticospinal tract atrophy (HP:0007117). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Progressive gait ataxia (HP:0007240): A type of gait ataxia displaying progression of clinical severity. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Retinal pigment epithelial mottling (HP:0007814): Mottling (spots or blotches of different shades) of the retinal pigment epithelium, i.e., localized or generalized fundus pigment granularity associated with processes at the level of the retinal pigment epithelium. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Severe intellectual disability (HP:0010864): Severe intellectual disability (ID) is defined as a type of ID characterized by severely sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 20-34. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Abnormal basal ganglia MRI signal intensity (HP:0012751): A deviation from normal signal on magnetic resonance imaging (MRI) of the basal ganglia. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
- Abnormal visual field test (HP:0030588): Abnormal result of a test designed to test an individual's central and peripheral vision by determining the ability of the individual to perceive objects at differing locations of the visual field. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:644)
These phenotypes are associated with the disease NARP syndrome (ORPHA:644).
The following phenotypes are NOT associated with this disease:
- Abnormal mitochondria in muscle tissue (HP:0008316): An abnormality of the mitochondria in muscle tissue. Evidence: TAS. (ORPHA:644)