{"Name":"Ring chromosome 21","DiseaseID__c":"GARD:0006083","id":6083,"encodedName":"ring-chromosome-21","IsDeleted":false,"Disease_Name_Full__c":"Ring chromosome 21","Xref_IDs__c":"31325007; C2931422; C537109; MEDGEN:419409; MONDO:0015437; ORPHA:1445","USA_Estimate__c":null,"No_of_Specialist_Tagsa__c":2,"No_of_ClinGen_records__c":0,"No_of_GeneReviews__c":0,"No_of_HHS_records__c":0,"World_Estimate__c":null,"No_of_HRSA_records__c":0,"Evidence_Based_Score__c":0,"No_of_Disease_Descriptions__c":2,"Disease_Characteristics_Score__c":7,"No_of_Age_at_Onset__c":2,"Description_Source__c":"MONDO:0015437","Disease_Description__c":"Ring chromosome 21 syndrome is an autosomal anomaly characterized by variable clinical features, most commonly including growth retardation, developmental delay, intellectual disability, epilepsy, microcephaly, short stature, dysmorphic features, hypogammaglobulinemia, thrombocytopenia and unspecific skeletal anomalies (hemivertebrae, clinodactyly, syndactyly). In rare cases, it has been described in phenotypically normal individuals.","GARD_Name__c":"Ring chromosome 21","GARD_Synonym__c":"chromosome 21 en anneau; chromosome 21 ring; ring chromosome 21 syndrome; ring chromosome type 21","Curated_Disease_Description_Source__c":"GARD:0006083","Curated_Disease_Description__c":"Ring chromosome 21 is a rare chromosome abnormality in which the ends of chromosome 21 join together to form a ring shape. Many people with Ring chromosome 21 have normal development and are healthy, having been diagnosed after having chromosome testing due to infertility, multiple miscarriages, or a child with a chromosome abnormality. However, others with Ring chromosome 21 have developmental and/or medical problems which can range from mild to severe. This is due to having extra or missing genetic material on the ring chromosome, which can happen when the ring chromosome forms. Signs and symptoms of Ring chromosome 21 that may be present can include short stature, delayed puberty in males, small head size, seizures, learning disabilities, underdeveloped sex organs, susceptibility to infections, and/or a variety of birth defects. Some people have signs and symptoms similar to those that occur in people with Down syndrome (also known as Trisomy 21). Ring chromosome 21 may be inherited from a parent (typically the mother), or it may occur sporadically (by chance) during the formation of egg or sperm cells or shortly after the egg and sperm join together. A chromosome test of the parents can help determine whether it was inherited and whether future children have an increased chance to have a chromosome abnormality.","Curated_USA_Estimate_Source__c":null,"Curated_USA_Estimate__c":null,"Age_at_Onset_Snippet_Text__c":"during Pregnancy and as a Newborn","SourceID__c":"ORPHA:1445","Deprecated__c":"No","Disease_Concept_Type__c":"Rare Disease Entity","MONDO_ID__c":"MONDO:0015437","ORPHANET_ID__c":"ORPHA:1445","Replaced_By_ID__c":null,"Display_Spanish_Disease_Name__c":"Síndrome del cromosoma 21 en anillo","Spanish_Description_Source__c":"ORPHA:1445","Spanish_Description__c":"Es una anomalía autosómica caracterizada por manifestaciones clínicas variables que, por lo general, incluyen retraso del crecimiento y del desarrollo, discapacidad intelectual, epilepsia, microcefalia, talla baja, características dismórficas, hipogammaglobulinemia, trombocitopenia y anomalías esqueléticas inespecíficas (hemivértebras, clinodactilia, sindactilia). En algunos casos, se ha descrito en individuos fenotípicamente normales.","Spanish_Disease_Name__c":"síndrome del cromosoma 21 en anillo","Spanish_GARD_Synonym__c":"anillo 21; cromosoma 21 en anillo","Category_Linearization__c":"ORPHA:93890","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":"Ring chromosome 21 is a rare chromosome abnormality in which the ends of chromosome 21 join together to form a ring shape. Many people with Ring chromosome 21 have normal development and are healthy, having been diagnosed after having chromosome testing due to infertility, multiple miscarriages, or a child with a chromosome abnormality. However, others with Ring chromosome 21 have developmental and/or medical problems which can range from mild to severe. This is due to having extra or missing genetic material on the ring chromosome, which can happen when the ring chromosome forms. Signs and symptoms of Ring chromosome 21 that may be present can include short stature, delayed puberty in males, small head size, seizures, learning disabilities, underdeveloped sex organs, susceptibility to infections, and/or a variety of birth defects. Some people have signs and symptoms similar to those that occur in people with Down syndrome (also known as Trisomy 21). Ring chromosome 21 may be inherited from a parent (typically the mother), or it may occur sporadically (by chance) during the formation of egg or sperm cells or shortly after the egg and sperm join together. A chromosome test of the parents can help determine whether it was inherited and whether future children have an increased chance to have a chromosome abnormality.","Curated_Disease_Description_Source__c":"GARD:0006083","GARD_Synonym__c":"chromosome 21 en anneau; chromosome 21 ring; ring chromosome 21 syndrome; ring chromosome type 21","Name":"Ring chromosome 21","estimateUsa":""}],"Organization_Supported_Diseases__c":[{"Account_Name__c":"Chromosome Disorder Outreach","Website__c":"https://chromodisorder.org/"},{"Account_Name__c":"Unique","Website__c":"https://rarechromo.org/"}],"GARD_Disease_Tag__c":[{"Tag_Name__c":"Chromosomal Anomaly","Tag_Category__c":"Account;Cause","curated_tag_name":"Chromosome disorders"},{"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":"Congenital Abnormality","Tag_Category__c":"Disease Category","category_description":"Birth defects are structural changes present at birth that can affect almost any part of the body, including how the body looks, works, or both.","curated_tag_name":"Birth defects"},{"Tag_Name__c":"Pediatrics","Tag_Category__c":"Specialist"}],"Age_At_Onset__c":[{"Age_At_Onset__c":"Antenatal","Provided_By__c":"ORPHA:1445"},{"Age_At_Onset__c":"Neonatal","Provided_By__c":"ORPHA:1445"}],"Diagnosis__c":[{"Type__c":"GTR","Curie__c":"MEDGEN:CN037252"}],"External_Identifier_Disease__c":[{"URL__c":"https://www.ncbi.nlm.nih.gov/medgen/?term=419409","Source__c":"C2931422","Xref__c":"MEDGEN:419409"},{"URL__c":"https://uts.nlm.nih.gov/uts/umls/concept/C2931422","Source__c":"C2931422","Xref__c":"C2931422"},{"URL__c":"https://browser.ihtsdotools.org/?perspective=full&conceptId1=31325007","Source__c":"MONDO:0015437","Xref__c":"31325007"},{"URL__c":"https://www.ncbi.nlm.nih.gov/mesh/C537109","Source__c":"MONDO:0015437","Xref__c":"C537109"},{"URL__c":"https://www.orpha.net/en/disease/detail/1445","Source__c":"C2931422; MONDO:0015437","Xref__c":"ORPHA:1445"},{"URL__c":"http://purl.obolibrary.org/obo/MONDO_0015437","Source__c":"GARD:0006083","Xref__c":"MONDO:0015437"}],"GARD_Disease_Feature__c":[{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"An abnormally decreased level of immunoglobulin in blood.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0004313","HPO_Synonym__c":"Decreased antibody level in blood; Decreased circulating antibody level; Decreased immunoglobulin level; Decreased serum immunoglobulin; Hypogammaglobulinemia; Immunoglobulin deficiency; Reduced immunoglobulin levels","HPO_Name__c":"Decreased circulating immunoglobulin concentration","Feature_System__c":"Immune System; Blood and Blood-Forming Tissue","HPO_Feature_Type__c":"Lab"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A short generalized seizure, of a duration of <15 min, not recurring within 24 h, occurring during a febrile episode not caused by an acute disease of the nervous system intracranial infection or severe metabolic disturbance.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0011171","HPO_Synonym__c":"Simple febrile convulsion; Simple febrile seizures; Simple fever fit","HPO_Name__c":"Simple febrile seizure","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Absence of menses for an interval of time equivalent to a total of more than (or equal to) 3 previous cycles or 6 months.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000141","HPO_Synonym__c":"Abnormal absence of menstruation","HPO_Name__c":"Amenorrhea","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A generalized myoclonic seizure is a type of generalized motor seizure characterized by bilateral, sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002123","HPO_Synonym__c":"Generalised epileptic myoclonus; Generalised myoclonic seizure; Generalized epileptic myoclonus; Generalized myoclonic seizures; Myoclonus seizures","HPO_Name__c":"Generalized myoclonic seizure","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","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:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Webbing or fusion of the fingers or toes, involving soft parts only or including bone structure. Bony fusions are referred to as \\\"bony\\\" syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the fingers or toes in a proximo-distal axis are referred to as \\\"symphalangism\\\".","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001159","HPO_Synonym__c":"Webbed fingers or toes","HPO_Name__c":"Syndactyly","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001249","HPO_Synonym__c":"Intellectual disability; Mental deficiency; Mental retardation; Mental retardation, nonspecific; Mental-retardation; Nonprogressive intellectual disability; Nonprogressive mental retardation","HPO_Name__c":"Intellectual disability","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"An angulation of a digit at an interphalangeal joint in the plane of the palm (finger) or sole (toe).","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0030084","HPO_Synonym__c":"Permanent curving of the finger","HPO_Name__c":"Clinodactyly","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A congenital anomaly characterized by a joining (fusion) of two or more thoracic vertebral bodies with one another.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0030039","HPO_Name__c":"Fused thoracic vertebrae","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Absence of any measurable level of sperm,whereby spermatozoa cannot be observed even after centrifugation of the semen pellet.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000027","HPO_Synonym__c":"Absent sperm in semen","HPO_Name__c":"Azoospermia","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"An abnormal morphology (form) of the face or its components.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001999","HPO_Synonym__c":"Abnormal facial shape; Abnormal morphology of the face; Distinctive facies; Dysmorphic facial features; Dysmorphic facies; Facial dysmorphism; Unusual facial appearance; Unusual facies","HPO_Name__c":"Abnormal facial shape","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Any structural anomaly of the heart.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001627","HPO_Synonym__c":"Abnormality of cardiac morphology; Abnormality of the heart; Abnormally shaped heart; Cardiac abnormality; Cardiac anomalies; Cardiac anomaly; Congenital heart defect; Congenital heart defects; Heart defect","HPO_Name__c":"Abnormal heart morphology","Feature_System__c":"Cardiovascular System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"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.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001263","HPO_Synonym__c":"Delayed cognitive development; Delayed development; Delayed developmental milestones; Delayed intellectual development; Delayed milestones; Delayed psychomotor development; Developmental delay; Developmental delay in early childhood; Developmental delay, global; Developmental retardation; GDD; Lack of psychomotor development; Motor and developmental delay; Motormental retardation; Psychomotor delay; Psychomotor development deficiency; Psychomotor development failure; Psychomotor developmental delay; Retarded development; Retarded mental development; Retarded psychomotor development","HPO_Name__c":"Global developmental delay","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"For children from birth to 4 years of age, the palm width is more than 2 SD below the mean; for children from 4 to 16 years of age the palm width is below the 5th centile; or, the width of the palm appears disproportionately narrow for its length.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0004283","HPO_Synonym__c":"Narrow hand; Narrow palm","HPO_Name__c":"Narrow palm","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"An increased sensitivity of the skin to light. Photosensitivity may result in a rash upon exposure to the sun (which is known as photodermatosis). Photosensitivity can be diagnosed by phototests in which light is shone on small areas of skin.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000992","HPO_Synonym__c":"Photosensitive skin; Photosensitive skin rashes; Photosensitivity; Sensitivity to sunlight; Skin photosensitivity; Sun sensitivity","HPO_Name__c":"Cutaneous photosensitivity","Feature_System__c":"Skin System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Head circumference below 2 standard deviations below the mean for age and sex.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000252","HPO_Synonym__c":"Abnormally small cranium; Abnormally small skull; Decreased circumference of cranium; Decreased size of cranium; Decreased size of skull; Reduced head circumference; small cranium; Small head circumference","HPO_Name__c":"Microcephaly","Feature_System__c":"Nervous System; Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","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:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A state of excessive water intake and hypotonic (dilute) polyuria. Diabetes insipidus may be due to failure of vasopressin (AVP) release (central or neurogenic diabetes insipidus) or to a failure of the kidney to respond to AVP (nephrogenic diabetes insipidus).","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000873","HPO_Name__c":"Diabetes insipidus","Feature_System__c":"Endocrine System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"The presence of an abnormal lateral curvature of the spine.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002650","HPO_Name__c":"Scoliosis","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"The presence of six or more cafe-au-lait spots.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0007565","HPO_Name__c":"Multiple cafe-au-lait spots","Feature_System__c":"Skin System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Disproportionately small hand.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0200055","HPO_Synonym__c":"Disproportionately small hands; Small hand","HPO_Name__c":"Small hand","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Holoprosencephaly is a structural anomaly of the brain in which the developing forebrain fails to divide into two separate hemispheres and ventricles.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001360","HPO_Synonym__c":"Single brain ventricle","HPO_Name__c":"Holoprosencephaly","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","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:1445","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:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A bilateral tonic-clonic seizure with generalized onset is a type of bilateral tonic-clonic seizure characterized by generalized onset; these seizures rapidly engage networks in both hemispheres at the start of the seizure.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0025190","HPO_Synonym__c":"Generalised tonic-clonic seizure without focal onset; Generalised tonic-clonic seizure without partial onset; Generalised tonic-clonic seizures without focal onset; Generalised-onset tonic-clonic seizure; Generalized tonic-clonic seizure without focal onset; Generalized tonic-clonic seizure without partial onset; Generalized tonic-clonic seizures without focal onset; Generalized-onset tonic-clonic seizure; Primarily generalized tonic-clonic seizures; Primary generalized tonic-clonic seizure; Primary generalized tonic-clonic seizures","HPO_Name__c":"Bilateral tonic-clonic seizure with generalized onset","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A height below that which is expected according to age and sex 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 sex (or below the 3rd percentile for age and sex dependent norms).","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0004322","HPO_Synonym__c":"Decreased body height; Height less than 3rd percentile; Short stature; Small stature; Stature below 3rd percentile","HPO_Name__c":"Short stature","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002353","HPO_Synonym__c":"Abnormal EEG; Abnormal electroencephalogram; EEG abnormalities; Electroencephalogram abnormal; Electroencephalogram abnormalities","HPO_Name__c":"EEG abnormality","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Procedure_EEG"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000789","HPO_Synonym__c":"Infertility","HPO_Name__c":"Infertility","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Any abnormality of the thorax (the region of the body formed by the sternum, the thoracic vertebrae and the ribs).","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000765","HPO_Synonym__c":"Abnormality of the chest; Abnormality of the thorax; Structural abnormality of the chest wall","HPO_Name__c":"Abnormal thorax morphology","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:1445","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"Absence of one half of the vertebral body in the thoracic spine.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0008467","HPO_Name__c":"Thoracic hemivertebrae","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}}],"tags":{"Account":["Chromosomal Anomaly"],"Cause":["Chromosomal Anomaly","Genetics"],"Disease Category":["Genetics","Congenital Abnormality"],"Specialist":["Genetics","Pediatrics"]},"synonyms":["chromosome 21 en anneau"," chromosome 21 ring"," ring chromosome 21 syndrome"," ring chromosome type 21"]}