- Abnormal EKG (HP:0003115): Abnormal rhythm of the heart. Evidence: IEA. (OMIM:229300)
- Mitochondrial malic enzyme reduced (HP:0003232). Evidence: TAS. (OMIM:229300)
- 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: TAS. (OMIM:229300)
- 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. (OMIM:229300)
- Diabetes mellitus (HP:0000819): A group of abnormalities characterized by hyperglycemia and glucose intolerance. Evidence: IEA. (OMIM:229300)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: IEA. (OMIM:229300)
- Reduced visual acuity (HP:0007663). Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:229300)
- Decreased pyruvate carboxylase activity (HP:0003209): A decreased rate of pyruvate carboxylase activity. Evidence: IEA. (OMIM:229300)
- Abnormality of the cardiovascular system (HP:0001626): Any abnormality of the cardiovascular system. Evidence: TAS. (OMIM:229300)
- Decreased sensory nerve conduction velocity (HP:0003448): Reduced speed of conduction of the action potential along a sensory nerve. Evidence: PCS. (PMID:6231891)
- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: IEA. (OMIM:229300)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: IEA. (OMIM:229300)
- 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: IEA. (OMIM:229300)
- 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: IEA. (OMIM:229300)
- Visual field defect (HP:0001123). Evidence: TAS. (OMIM:229300)
- 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: IEA. (OMIM:229300)
- Impaired vibratory sensation (HP:0002495): A decrease in the ability to perceive vibration. Clinically, this is usually tested with a tuning fork which vibrates at 128 Hz and is applied to bony prominences such as the malleoli at the ankles or the metacarpal-phalangeal joints. There is a slow decay of vibration from the tuning fork. The degree of vibratory sense loss can be crudely estimated by counting the number of seconds that the examiner can perceive the vibration longer than the patient. Evidence: IEA. (OMIM:229300)
- Limb ataxia (HP:0002070): A kind of ataxia that affects movements of the extremities. Evidence: TAS. (OMIM:229300)
- Impaired proprioception (HP:0010831): A loss or impairment of the sensation of the relative position of parts of the body and joint position. Evidence: TAS. (OMIM:229300)
- Hypertrophic cardiomyopathy (HP:0001639): Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality. Evidence: TAS. (OMIM:229300)
- Abnormality of visual evoked potentials (HP:0000649): An anomaly of visually evoked potentials (VEP), which are electrical potentials, initiated by brief visual stimuli, which are recorded from the scalp overlying the visual cortex. Evidence: TAS. (OMIM:229300)
- Decreased amplitude of sensory action potentials (HP:0007078): A reduction in the amplitude of sensory nerve action potential. This feature is measured by nerve conduction studies. Evidence: PCS. (PMID:6231891)
- Autosomal recessive inheritance (HP:0000007): 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 individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: IEA. (OMIM:229300)
- Congestive heart failure (HP:0001635): The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction. Evidence: TAS. (OMIM:229300)
- 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. (OMIM:229300)
- 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: Occasional (HP:0040283). (OMIM:229300)
- Sensory neuropathy (HP:0000763): Peripheral neuropathy affecting the sensory nerves. Evidence: TAS. (OMIM:229300)
- Areflexia of lower limbs (HP:0002522): Inability to elicit tendon reflexes in the lower limbs. Evidence: IEA. (OMIM:229300)
These phenotypes are associated with the disease Friedreich ataxia 1 (OMIM:229300).