- 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: Very frequent (HP:0040281). (ORPHA:2802)
- Anemia (HP:0001903): A reduction in erythrocytes volume or hemoglobin concentration. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:2802)
- 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. Frequency: Very frequent (HP:0040281). (ORPHA:2802)
- Abnormal speech pattern (HP:0002167): An abnormality in the sound (volume) or cadence (rate) of speech. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:2802)
- Increased erythrocyte protoporphyrin concentration (HP:0012187): Concentration of protoporphyrins in erythrocytes above the upper limit of normal. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:2802)
- Delayed ability to walk (HP:0031936): A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:2802)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- 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:2802)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- 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: Frequent (HP:0040282). (ORPHA:2802)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Brisk reflexes (HP:0001348): Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Sideroblastic anemia (HP:0001924): Sideroblastic anemia results from a defect in the incorporation of iron into the heme molecule. A sideroblast is an erythroblast that has stainable deposits of iron in cytoplasm (this can be demonstrated by Prussian blue staining). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Postural instability (HP:0002172): A tendency to fall or the inability to keep oneself from falling; imbalance. The retropulsion test is widely regarded as the gold standard to evaluate postural instability, Use of the retropulsion test includes a rapid balance perturbation in the backward direction, and the number of balance correcting steps (or total absence thereof) is used to rate the degree of postural instability. Healthy subjects correct such perturbations with either one or two large steps, or without taking any steps, hinging rapidly at the hips while swinging the arms forward as a counterweight. In patients with balance impairment, balance correcting steps are often too small, forcing patients to take more than two steps. Taking three or more steps is generally considered to be abnormal, and taking more than five steps is regarded as being clearly abnormal. Markedly affected patients continue to step backward without ever regaining their balance and must be caught by the examiner (this would be called true retropulsion). Even more severely affected patients fail to correct entirely, and fall backward like a pushed toy soldier, without taking any corrective steps. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Delayed gross motor development (HP:0002194): A type of motor delay characterized by a delay in acquiring the ability to control the large muscles of the body for walking, running, sitting, and crawling. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Hypochromic microcytic anemia (HP:0004840): A type of anemia characterized by an abnormally low concentration of hemoglobin in the erythrocytes and lower than normal size of the erythrocytes. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Anisocytosis (HP:0011273): Abnormally increased variability in the size of erythrocytes. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:2802)
- Autism (HP:0000717): Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- 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: Occasional (HP:0040283). (ORPHA:2802)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- Dysdiadochokinesis (HP:0002075): A type of ataxia characterized by the impairment of the ability to perform rapidly alternating movements, such as pronating and supinating his or her hand on the dorsum of the other hand as rapidly as possible. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- Poikilocytosis (HP:0004447): The presence of abnormally shaped erythrocytes. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- Pappenheimer bodies (HP:0020081): A type of erythrocyte inclusion characterized by basophilic stippling of erythrocytes, that is, by numerous very small coarse or fine blue granules within the cytoplasm with the additional stipulation that the stippled particles are due to iron granules (demonstrable by the Prussian blue stain). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- Increased bone marrow iron (HP:0034499): An increased amount of iron in the bone marrow. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:2802)
- Cryptorchidism (HP:0000028): Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:2802)
- Depression (HP:0000716): Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:2802)
- 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: Very rare (HP:0040284). (ORPHA:2802)
- Organic aciduria (HP:0001992): Excretion of non-amino organic acids in urine. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:2802)
- Cognitive impairment (HP:0100543): Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:2802)
- Schizophrenia (HP:0100753): A mental disorder characterized by a disintegration of thought processes and emotional responsiveness. It most commonly manifests as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking. It is accompanied by significant social or occupational dysfunction. The onset of symptoms typically occurs in young adulthood, with a global lifetime prevalence of about 1%. This term is not a helpful parent term to describe abnormal experiences. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:2802)
These phenotypes are associated with the disease X-linked sideroblastic anemia and spinocerebellar ataxia (ORPHA:2802).