{"Name":"Infantile neuroaxonal dystrophy","DiseaseID__c":"GARD:0003957","id":3957,"encodedName":"infantile-neuroaxonal-dystrophy","IsDeleted":false,"Disease_Name_Full__c":"Infantile neuroaxonal dystrophy","Xref_IDs__c":"423022195; 52713000; C0270724; C536071; C84927; DOID:0110735; MEDGEN:82852; MONDO:0024457; OMIM:256600; ORPHA:35069","USA_Estimate__c":null,"No_of_Specialist_Tagsa__c":5,"No_of_ClinGen_records__c":0,"No_of_GeneReviews__c":0,"No_of_HHS_records__c":3,"World_Estimate__c":null,"No_of_HRSA_records__c":0,"Evidence_Based_Score__c":3,"No_of_Disease_Descriptions__c":2,"Disease_Characteristics_Score__c":8,"No_of_Age_at_Onset__c":2,"Description_Source__c":"GARD:0003957","Disease_Description__c":"Infantile neuroaxonal dystrophy is a type of lipid storage disorder that mostly affects the nervous system. It has two forms, a classic form and an atypical form. Infantile neuroaxonal dystrophy is caused by changes (pathogenic variants) in the PLA2G6 gene and is inherited in an autosomal recessive pattern.","GARD_Name__c":"Infantile neuroaxonal dystrophy","GARD_Synonym__c":"inad; inad - infantile neuroaxonal dystrophy; inad1; infantile neuroaxonal dystrophy 1; nbia2a; neurodegeneration with brain iron accumulation 2a; neurodegeneration with brain iron accumulation type 2a; neurodegeneration, pla2g6-associated; plan; seitelberger's disease; spastic amaurotic axonal idiocy","Curated_Disease_Description_Source__c":"GARD:0003957","Curated_Disease_Description__c":"Infantile neuroaxonal dystrophy is a disorder that primarily affects the nervous system. Individuals with infantile neuroaxonal dystrophy typically do not have any symptoms at birth, but between the ages of about 6 and 18 months they begin to experience delays in acquiring new motor and intellectual skills, such as crawling or beginning to speak. Eventually they lose previously acquired skills (developmental regression). In some cases, signs and symptoms of infantile neuroaxonal dystrophy first appear later in childhood or during the teenage years and progress more slowly. Children with infantile neuroaxonal dystrophy experience progressive difficulties with movement. They generally have muscles that are at first weak and 'floppy' (hypotonic), and then gradually become very stiff (spastic). Eventually, affected children lose the ability to move independently. Lack of muscle strength causes difficulty with feeding. Muscle weakness can also result in breathing problems that can lead to frequent infections, such as pneumonia. Seizures occur in some affected children. Rapid, involuntary eye movements (nystagmus), eyes that do not look in the same direction (strabismus), and vision loss due to deterioration (atrophy) of the nerve that carries information from the eye to the brain (the optic nerve) often occur in infantile neuroaxonal dystrophy. Hearing loss may also develop. Children with this disorder experience progressive deterioration of cognitive functions (dementia), and they eventually lose awareness of their surroundings. Infantile neuroaxonal dystrophy is characterized by the development of swellings called spheroid bodies in the axons, the fibers that extend from nerve cells (neurons) and transmit impulses to muscles and other neurons. In some individuals with infantile neuroaxonal dystrophy, abnormal amounts of iron accumulate in a specific region of the brain called the basal ganglia. The relationship of these features to the symptoms of infantile neuroaxonal dystrophy is unknown.","Curated_USA_Estimate_Source__c":null,"Curated_USA_Estimate__c":null,"Age_at_Onset_Snippet_Text__c":"as a Newborn and as an Infant","SourceID__c":"ORPHA:35069","Deprecated__c":"No","Disease_Concept_Type__c":"Rare Disease Entity","MONDO_ID__c":"MONDO:0024457","ORPHANET_ID__c":"ORPHA:35069","Replaced_By_ID__c":null,"Display_Spanish_Disease_Name__c":"Distrofia neuroaxonal infantil","Spanish_Description_Source__c":null,"Spanish_Description__c":null,"Spanish_Disease_Name__c":"distrofia neuroaxonal infantil","Spanish_GARD_Synonym__c":"enfermedad de seitelberger; inad; inad1; neurodegeneración asociada a fosfolipasa a2","Category_Linearization__c":"ORPHA:98006","icd10_id__c":null,"mesh_id__c":null,"omim_id__c":null,"snomed_id__c":null,"umls_id__c":null,"GARD_Disease__c":[{"Curated_Disease_Description__c":"Infantile neuroaxonal dystrophy is a disorder that primarily affects the nervous system. Individuals with infantile neuroaxonal dystrophy typically do not have any symptoms at birth, but between the ages of about 6 and 18 months they begin to experience delays in acquiring new motor and intellectual skills, such as crawling or beginning to speak. Eventually they lose previously acquired skills (developmental regression). In some cases, signs and symptoms of infantile neuroaxonal dystrophy first appear later in childhood or during the teenage years and progress more slowly. Children with infantile neuroaxonal dystrophy experience progressive difficulties with movement. They generally have muscles that are at first weak and 'floppy' (hypotonic), and then gradually become very stiff (spastic). Eventually, affected children lose the ability to move independently. Lack of muscle strength causes difficulty with feeding. Muscle weakness can also result in breathing problems that can lead to frequent infections, such as pneumonia. Seizures occur in some affected children. Rapid, involuntary eye movements (nystagmus), eyes that do not look in the same direction (strabismus), and vision loss due to deterioration (atrophy) of the nerve that carries information from the eye to the brain (the optic nerve) often occur in infantile neuroaxonal dystrophy. Hearing loss may also develop. Children with this disorder experience progressive deterioration of cognitive functions (dementia), and they eventually lose awareness of their surroundings. Infantile neuroaxonal dystrophy is characterized by the development of swellings called spheroid bodies in the axons, the fibers that extend from nerve cells (neurons) and transmit impulses to muscles and other neurons. In some individuals with infantile neuroaxonal dystrophy, abnormal amounts of iron accumulate in a specific region of the brain called the basal ganglia. The relationship of these features to the symptoms of infantile neuroaxonal dystrophy is unknown.","Curated_Disease_Description_Source__c":"GARD:0003957","GARD_Synonym__c":"inad; inad - infantile neuroaxonal dystrophy; inad1; infantile neuroaxonal dystrophy 1; nbia2a; neurodegeneration with brain iron accumulation 2a; neurodegeneration with brain iron accumulation type 2a; neurodegeneration, pla2g6-associated; plan; seitelberger's disease; spastic amaurotic axonal idiocy","Name":"Infantile neuroaxonal dystrophy","estimateUsa":""}],"Organization_Supported_Diseases__c":[{"Account_Name__c":"NBIAcure","Website__c":"https://nbiacure.org/"},{"Account_Name__c":"Childhood Dementia Initiative","Website__c":"https://www.childhooddementia.org/"},{"Account_Name__c":"NBIA Disorders Association","Website__c":"https://www.nbiadisorders.org/"}],"GARD_Disease_Tag__c":[{"Tag_Name__c":"Genetics","Tag_Category__c":"Cause;Disease Category;Specialist","category_description":"Genetic diseases affect the DNA, or genetic instructions, which directs how tissues, organs, and body systems function.","curated_tag_name":"Genetic diseases"},{"Tag_Name__c":"Neurology","Tag_Category__c":"Disease Category;Specialist","category_description":"Neurological diseases affect the brain, spinal cord, cranial nerves, autonomic nerves, or other peripheral nerves.","curated_tag_name":"Neurological diseases"},{"Tag_Name__c":"Psychiatry","Tag_Category__c":"Specialist"},{"Tag_Name__c":"Inborn Errors of Metabolism","Tag_Category__c":"Cause;Disease Category","category_description":"Inherited metabolic diseases, or inborn errors of metabolism, are a group of genetic diseases that affect the ability of the body's cells to convert food into energy.","curated_tag_name":"Inherited metabolic diseases"},{"Tag_Name__c":"Peripheral Neuropathy","Tag_Category__c":"Account","curated_tag_name":"Peripheral neuropathy"},{"Tag_Name__c":"Neuromuscular medicine","Tag_Category__c":"Specialist","curated_tag_name":"Neuromuscular medicine"},{"Tag_Name__c":"Pediatrics","Tag_Category__c":"Specialist"}],"Age_At_Onset__c":[{"Age_At_Onset__c":"Neonatal","Provided_By__c":"ORPHA:35069"},{"Age_At_Onset__c":"Infancy","Provided_By__c":"ORPHA:35069"}],"External_Identifier_Disease__c":[{"URL__c":"https://raresource.nih.gov/diseases/filter/0003957","Source__c":"RareSource"},{"URL__c":"https://www.ncbi.nlm.nih.gov/books/NBK1675","Source__c":"Gene Review","Xref__c":"NBK1675"},{"URL__c":"https://www.ncbi.nlm.nih.gov/books/NBK121988","Source__c":"Gene Review","Xref__c":"NBK121988"},{"URL__c":"https://www.omim.org/entry/256600","Source__c":"C0270724; MONDO:0024457; ORPHA:35069","Xref__c":"OMIM:256600"},{"URL__c":"https://uts.nlm.nih.gov/uts/umls/concept/C0270724","Source__c":"C0270724","Xref__c":"C0270724"},{"URL__c":"https://www.ncbi.nlm.nih.gov/medgen/?term=82852","Source__c":"C0270724","Xref__c":"MEDGEN:82852"},{"URL__c":"https://www.orpha.net/en/disease/detail/35069","Source__c":"C0270724; MONDO:0024457; ORPHA:35069","Xref__c":"ORPHA:35069"},{"URL__c":"https://www.ebi.ac.uk/ols4/ontologies/doid/classes?obo_id=DOID%3A0110735","Source__c":"MONDO:0024457","Xref__c":"DOID:0110735"},{"URL__c":"https://evsexplore.semantics.cancer.gov/evsexplore/concept/ncit/C84927","Source__c":"C0270724; MONDO:0024457","Xref__c":"C84927"},{"URL__c":"https://browser.ihtsdotools.org/?perspective=full&conceptId1=52713000","Source__c":"C0270724; MONDO:0024457","Xref__c":"52713000"},{"URL__c":"https://www.ncbi.nlm.nih.gov/mesh/C536071","Source__c":"MONDO:0024457","Xref__c":"C536071"},{"URL__c":"https://medlineplus.gov/genetics/condition/infantile-neuroaxonal-dystrophy","Source__c":"GARD:0003957","Xref__c":"https://medlineplus.gov/genetics/condition/infantile-neuroaxonal-dystrophy"},{"URL__c":"http://purl.obolibrary.org/obo/MONDO_0024457","Source__c":"GARD:0003957","Xref__c":"MONDO:0024457"},{"URL__c":"https://secure.ssa.gov/apps10/poms.nsf/lnx/0423022195","Xref__c":"423022195"},{"URL__c":"https://www.ninds.nih.gov/health-information/disorders/infantile-neuroaxonal-dystrophy"},{"URL__c":"https://evsexplore.semantics.cancer.gov/evsexplore/concept/ncit/C202073","Source__c":"C0270724","Xref__c":"C202073"}],"GARD_Disease_Gene__c":[{"GeneSymbol__c":"PLA2G6","GHR_URL__c":"https://medlineplus.gov/genetics/gene/pla2g6","Gene_Type__c":"protein-coding gene","Causal_Gene__c":true}],"Inheritance__c":["Autosomal recessive"],"GARD_Disease_Feature__c":[{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Uncommon (<1-4%)","Feature__r":{"HPO_Description__c":"Incidents in which a piece of food or other objects get stuck in the upper airway and provoke coughing, gagging, inability to talk, and difficulty breathing.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0030842","HPO_Name__c":"Choking episodes","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000648","HPO_Synonym__c":"Optic nerve atrophy; Optic-nerve degeneration","HPO_Name__c":"Optic atrophy","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Loss of previously present mental and motor abilities.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002361","HPO_Synonym__c":"Psychomotor degeneration","HPO_Name__c":"Psychomotor deterioration","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000729","HPO_Synonym__c":"ASD; Pervasive developmental disorder","HPO_Name__c":"Autistic behavior","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Pneumonia due to the aspiration (breathing in) of food, liquid, or gastric contents into the upper respiratory tract.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0011951","HPO_Name__c":"Aspiration pneumonia","Feature_System__c":"Respiratory system; Immune System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0003405","HPO_Name__c":"Diffuse axonal swelling","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000752","HPO_Synonym__c":"Hyperactive behavior; Hyperkinetic disorder; More active than typical","HPO_Name__c":"Hyperactivity","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Habitual flow of saliva out of the mouth.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002307","HPO_Synonym__c":"Dribbling; Drooling; Sialorrhea","HPO_Name__c":"Drooling","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Rhythmic, involuntary sinusoidal oscillations of one or both eyes. The waveform of pendular nystagmus may occur in any direction.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0012043","HPO_Name__c":"Pendular nystagmus","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"An elevated level of the enzyme lactate dehydrogenase in the blood circulation.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0025435","HPO_Synonym__c":"Increased circulating LDH concentration; Increased lactate dehydrogenase level","HPO_Name__c":"Increased circulating lactate dehydrogenase concentration","HPO_Feature_Type__c":"Lab"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001371","HPO_Synonym__c":"Flexed joint that cannot be straightened; Flexion contractures; Flexion contractures of joints","HPO_Name__c":"Flexion contracture","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Focal proliferation of glial cells in the cerebellum.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0012698","HPO_Name__c":"Cerebellar gliosis","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Uncommon (<1-4%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001250","HPO_Synonym__c":"Epileptic seizure; Seizures","HPO_Name__c":"Seizure","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"The presence, on T2-weighted magnetic resonance imaging, of markedly low signal intensity of the globus pallidus that surrounds a central region of high signal intensity in the anteromedial globus pallidus, producing an eye-of-the-tiger appearance. The sign is thought to represent iron accumulation in the globus pallidus.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002454","HPO_Name__c":"Eye of the tiger anomaly of globus pallidus","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Imaging_MRI"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Spasticity that increases in degree with time.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002191","HPO_Synonym__c":"Spasticity, progressive","HPO_Name__c":"Progressive spasticity","Feature_System__c":"Nervous System; Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0008936","HPO_Synonym__c":"Low muscle tone in trunk; Muscular hypotonia of the trunk; Truncal hypotonia","HPO_Name__c":"Axial hypotonia","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001347","HPO_Synonym__c":"Increased deep tendon reflexes; Increased reflexes","HPO_Name__c":"Hyperreflexia","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0007141","HPO_Synonym__c":"Mixed polyneuropathy; Nerve damage causing decreased feeling and movement; Sensorimotor peripheral neuropathy","HPO_Name__c":"Sensorimotor neuropathy","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001260","HPO_Synonym__c":"Difficulty articulating speech; Dysarthric speech","HPO_Name__c":"Dysarthria","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000486","HPO_Synonym__c":"Cross-eyed; Squint; Squint eyes","HPO_Name__c":"Strabismus","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"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).","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001251","HPO_Synonym__c":"Cerebellar ataxia","HPO_Name__c":"Ataxia","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002483","HPO_Name__c":"Bulbar signs","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A degree of language development that is significantly below the norm for a child of a specified age.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000750","HPO_Synonym__c":"Deficiency of speech development; Delayed language development; Delayed speech; Delayed speech acquisition; Delayed speech and language development; Delayed speech development; Impaired speech and language development; Impaired speech development; Language delay; Language delayed; Language development deficit; Late-onset speech development; Poor language development; Speech and language delay; Speech and language difficulties; Speech delay","HPO_Name__c":"Delayed speech and language development","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Disordered thermoregulation characterized by an impaired ability to maintain a balance between heat production and heat loss, with resulting instability of body temperature.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0005968","HPO_Synonym__c":"Temperature instability","HPO_Name__c":"Temperature instability","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Uncommon (<1-4%)","Feature__r":{"HPO_Description__c":"A limitation of the ability to direct one's gaze above the horizontal meridian.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0025331","HPO_Synonym__c":"Supranuclear upgaze palsy; Upgaze paresis","HPO_Name__c":"Upgaze palsy","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Evidence of chronic denervation on electromyography.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0003444","HPO_Name__c":"EMG: chronic denervation signs","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Procedure_EMG"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A functional abnormality of the autonomic nervous system.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0012332","HPO_Synonym__c":"Autonomic dysfunction; Autonomic dysregulation; Dysautonomia","HPO_Name__c":"Abnormal autonomic nervous system physiology","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001257","HPO_Synonym__c":"Involuntary muscle stiffness, contraction, or spasm; Muscle spasticity; Muscular spasticity","HPO_Name__c":"Spasticity","Feature_System__c":"Nervous System; Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001272","HPO_Synonym__c":"Atrophic cerebellum; Degeneration of cerebellum","HPO_Name__c":"Cerebellar atrophy","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Infrequent or difficult evacuation of feces.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002019","HPO_Synonym__c":"Constipation; Costiveness; Dyschezia","HPO_Name__c":"Constipation","Feature_System__c":"Digestive System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Loss of developmental skills, as manifested by loss of developmental milestones.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002376","HPO_Synonym__c":"Loss of acquired milestones; Loss of developmental milestones; Loss of milestones; Mental deterioration in childhood; Neurodevelopmental regression; Psychomotor regression; Psychomotor regression beginning in infancy; Psychomotor regression in infants; Psychomotor regression, progressive","HPO_Name__c":"Developmental regression","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"An abnormal build up of iron (Fe) in brain tissue.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0012675","HPO_Synonym__c":"Brain iron deposition; Iron accumulation in brain","HPO_Name__c":"Iron accumulation in brain","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"An abnormality of the conduction of electrical impulses by peripheral (motor or sensory) nerves. 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While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000708","HPO_Synonym__c":"Behavioral abnormality; Behavioral changes; Behavioral disorders; Behavioral disturbances; Behavioral problems; Behavioral symptoms; Behavioral/psychiatric abnormalities; Behavioural symptoms; Behavioural/Psychiatric abnormality; Psychiatric disorders; Psychiatric disturbances","HPO_Name__c":"Atypical behavior","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Loss of previously present mental abilities, generally in adults.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001268","HPO_Synonym__c":"Cognitive decline; Cognitive decline, progressive; Intellectual deterioration; Mental deterioration; Progressive cognitive decline","HPO_Name__c":"Mental deterioration","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000649","HPO_Synonym__c":"Abnormal vision evoked potentials; Abnormal visual evoked potential; Abnormal visual evoked responses; Abnormal visual-evoked potentials; VEP abnormalities","HPO_Name__c":"Abnormality of visual evoked potentials","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"The term gait disturbance can refer to any disruption of the ability to walk.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001288","HPO_Synonym__c":"Abnormal gait; Abnormal walk; Difficulty in walking; Gait abnormalities; Gait difficulties; Gait disturbances; Impaired gait; Walking disability","HPO_Name__c":"Gait disturbance","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000639","HPO_Synonym__c":"Involuntary, rapid, rhythmic eye movements","HPO_Name__c":"Nystagmus","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000618","HPO_Synonym__c":"Blindness; Total vision loss","HPO_Name__c":"Blindness","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"An abnormality of the cerebral white matter.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002500","HPO_Synonym__c":"Abnormality of subcortical white matter; Abnormality of the cerebral white matter; Cerebral white matter abnormalities; Leukoaraiosis; White matter abnormalities; White matter alterations","HPO_Name__c":"Abnormal cerebral white matter morphology","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"An abnormally increased muscular tone that causes fixed abnormal postures. 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The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0009830","HPO_Synonym__c":"Peripheral nerve damage; Peripheral neuritis","HPO_Name__c":"Peripheral neuropathy","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Reduced attention span characterized by distractibility and impulsivity.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000736","HPO_Synonym__c":"Easily distracted; Easy distractibility; High distractibility; Poor attention span; Problem paying attention; Short attention span","HPO_Name__c":"Short attention span","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Uncommon (<1-4%)","Feature__r":{"HPO_Description__c":"Recurrent episodes of apnea occurring during infancy.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0005949","HPO_Name__c":"Apneic episodes in infancy","Feature_System__c":"Respiratory system","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Spastic weakness affecting all four limbs.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001285","HPO_Synonym__c":"Spastic quadriparesis","HPO_Name__c":"Spastic tetraparesis","Feature_System__c":"Nervous System; Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Acting on the spur of the moment or on a momentary basis without consideration of outcomes; having difficulty establishing or following plans; experiencing a sense of urgency and engaging in behavior that is uninhibited, cannot be inhibited, and is uncontrolled. The possibility of repression is inconceivable.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0100710","HPO_Synonym__c":"Impulsive; Impulsivity","HPO_Name__c":"Impulsivity","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:35069","HPO_Frequency__c":"Uncommon (<1-4%)","Feature__r":{"HPO_Description__c":"Downbeat nystagmus is a type of fixation nystagmus with the fast phase beating in a downward direction. 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