Phenotypes associated with the disease Ring chromosome 21 syndrome (ORPHA:1445):
- Intellectual disability (HP:0001249): 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. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1445)
- 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: Frequent (HP:0040282). (ORPHA:1445)
- 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:1445)
- Abnormal facial shape (HP:0001999): An abnormal morphology (form) of the face or its components. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1445)
- Amenorrhea (HP:0000141): Absence of menses for an interval of time equivalent to a total of more than (or equal to) 3 previous cycles or 6 months. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1445)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1445)
- Infertility (HP:0000789). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1445)
- EEG abnormality (HP:0002353): Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:1445)
- Azoospermia (HP:0000027): Absence of any measurable level of sperm,whereby spermatozoa cannot be observed even after centrifugation of the semen pellet. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- 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: Occasional (HP:0040283). (ORPHA:1445)
- Abnormal thorax morphology (HP:0000765): Any abnormality of the thorax (the region of the body formed by the sternum, the thoracic vertebrae and the ribs). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Diabetes insipidus (HP:0000873): 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). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Cutaneous photosensitivity (HP:0000992): 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. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Syndactyly (HP:0001159): 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". Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- 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: Occasional (HP:0040283). (ORPHA:1445)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Holoprosencephaly (HP:0001360): Holoprosencephaly is a structural anomaly of the brain in which the developing forebrain fails to divide into two separate hemispheres and ventricles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Abnormal heart morphology (HP:0001627): Any structural anomaly of the heart. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Generalized myoclonic seizure (HP:0002123): 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. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Narrow palm (HP:0004283): 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. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Decreased circulating immunoglobulin concentration (HP:0004313): An abnormally decreased level of immunoglobulin in blood. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- 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: Occasional (HP:0040283). (ORPHA:1445)
- Multiple cafe-au-lait spots (HP:0007565): The presence of six or more cafe-au-lait spots. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Thoracic hemivertebrae (HP:0008467): Absence of one half of the vertebral body in the thoracic spine. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Simple febrile seizure (HP:0011171): 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. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Bilateral tonic-clonic seizure with generalized onset (HP:0025190): 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. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Fused thoracic vertebrae (HP:0030039): A congenital anomaly characterized by a joining (fusion) of two or more thoracic vertebral bodies with one another. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Clinodactyly (HP:0030084): An angulation of a digit at an interphalangeal joint in the plane of the palm (finger) or sole (toe). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)
- Small hand (HP:0200055): Disproportionately small hand. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:1445)