- Hypogonadotropic hypogonadism (HP:0000044): Hypogonadotropic hypogonadism is characterized by reduced function of the gonads (testes in males or ovaries in females) and results from the absence of the gonadal stimulating pituitary hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Vertical supranuclear gaze palsy (HP:0000511): A supranuclear gaze palsy is an inability to look in a vertical direction as a result of cerebral impairment. There is a loss of the voluntary aspect of eye movements, but, as the brainstem is still intact, all the reflex conjugate eye movements are normal. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Myopia (HP:0000545): An abnormality of refraction characterized by the ability to see objects nearby clearly, while objects in the distance appear blurry. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Abnormality of ocular smooth pursuit (HP:0000617): An abnormality of eye movement characterized by impaired smooth-pursuit eye movements. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- 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:447896)
- Hypodontia (HP:0000668): The absence of five or less teeth from the normal series by a failure to develop. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Oligodontia (HP:0000677): The absence of six or more teeth from the normal series by a failure to develop. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Delayed eruption of teeth (HP:0000684): Delayed tooth eruption, which can be defined as tooth eruption more than 2 SD beyond the mean eruption age. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Delayed puberty (HP:0000823): Passing the age when puberty normally occurs with no physical or hormonal signs of the onset of puberty. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- 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:447896)
- Mild intellectual disability (HP:0001256): Mild intellectual disability (ID) is defined as a type of ID characterized by mildly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 50-69. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- 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:447896)
- Dysmetria (HP:0001310): A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Cerebellar hypoplasia (HP:0001321): Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Dystonia (HP:0001332): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Intention tremor (HP:0002080): A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Abnormal basal ganglia morphology (HP:0002134): Abnormality of the basal ganglia. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Postural tremor (HP:0002174): A type of tremors that is triggered by holding a limb in a fixed position. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Clumsiness (HP:0002312): Lack of physical coordination resulting in an abnormal tendency to drop items or bump into objects. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Positive Romberg sign (HP:0002403): The patient stands with the feet placed together and balance and is asked to close his or her eyes. A loss of balance upon eye closure is a positive Romberg sign and is interpreted as indicating a deficit in proprioception. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Leukodystrophy (HP:0002415): Leukodystrophy refers to deterioration of white matter of the brain resulting from degeneration of myelin sheaths in the CNS. Their basic defect is directly related to the synthesis and maintenance of myelin membranes. Symmetric white matter involvement at MRI is a typical finding in patients with leukodystrophies. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Spastic dysarthria (HP:0002464): A type of dysarthria related to bilateral damage of the upper motor neuron tracts of the pyramidal and extra- pyramidal tracts. Speech of affected individuals is slow, effortful, and has a harsh vocal quality. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- Upper motor neuron dysfunction (HP:0002493): A functional anomaly of the upper motor neuron. The upper motor neurons are neurons of the primary motor cortex which project to the brainstem and spinal chord via the corticonuclear, corticobulbar and corticospinal (pyramidal) tracts. They are involved in control of voluntary movements. Dysfunction leads to weakness, impairment of fine motor movements, spasticity, hyperreflexia and abnormal pyramidal signs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- CNS hypomyelination (HP:0003429): Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- 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:447896)
- 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:447896)
- Autonomic bladder dysfunction (HP:0005341): Abnormal bladder function (increased urge or frequency of urination or urge incontinence) resulting from abnormal functioning of the autonomic nervous system. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- High myoinositol in brain by MRS (HP:0025460): An elevated level of myoinositol in the brain identified by magnetic resonance spectroscopy (MRS). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:447896)
- 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: Occasional (HP:0040283). (ORPHA:447896)
- Cerebral cortical atrophy (HP:0002120): Atrophy of the cortex of the cerebrum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:447896)
- Impaired vibration sensation in the lower limbs (HP:0002166): A decrease in the ability to perceive vibration in the legs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:447896)
- Drooling (HP:0002307): Habitual flow of saliva out of the mouth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:447896)
- Impaired distal proprioception (HP:0006858): A loss or impairment of the sensation of the relative position of parts of the body and joint position occurring at distal joints. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:447896)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:447896)
- Deeply set eye (HP:0000490): An eye that is more deeply recessed into the plane of the face than is typical. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:447896)
- Focal-onset seizure (HP:0007359): A focal-onset seizure is a type of seizure originating within networks limited to one hemisphere. They may be discretely localized or more widely distributed, and may originate in subcortical structures. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:447896)
These phenotypes are associated with the disease Tremor-ataxia-central hypomyelination syndrome (ORPHA:447896).