Question: What is (are) TAR syndrome ?
Answer: TAR syndrome is characterized by the absence of a bone called the radius in each forearm, short stature, and thrombocytopenia. The thrombocytopenia often appears first in infancy but becomes less severe or returns to normal over time. Infants and young children are particularly vulnerable to episodes of severe bleeding which may occur in the brain and other organs. Children who survive this period and do not have damaging bleeding in the brain usually have a normal life expectancy and normal intellectual development. Other signs and symptoms vary but may include heart defects, kidney defects, and other skeletal abnormalities. About half of people with TAR syndrome also have difficulty digesting cow's milk. TAR syndrome is thought be caused by a deletion of genes on chromosome 1q21.1 in concert with another genetic change that has yet to be identified. Click here to see a diagram of chromosome 1.
Source: GARD

Question: What are the symptoms of TAR syndrome ?
Answer: What are the signs and symptoms of TAR syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for TAR syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Bilateral radial aplasia 100% Abnormality of coagulation 90% Aplasia/Hypoplasia of the ulna 90% Thrombocytopenia 90% Clinodactyly of the 5th finger 75% Cow milk allergy 75% Coxa valga 75% Eosinophilia 75% Genu varum 75% Hip dislocation 75% Patellar aplasia 75% Abnormality of the intestine 50% Adducted thumb 50% Aplasia/hypoplasia of the humerus 50% Broad forehead 50% Broad thumb 50% High forehead 50% Low-set, posteriorly rotated ears 50% Patellar dislocation 50% Death in infancy 40% Anemia 33% Abnormal localization of kidney 7.5% Abnormality of the cardiac septa 7.5% Abnormality of the shoulder 7.5% Carpal bone hypoplasia 7.5% Cavum septum pellucidum 7.5% Cerebellar hypoplasia 7.5% Cleft palate 7.5% Delayed CNS myelination 7.5% Edema of the dorsum of feet 7.5% Edema of the dorsum of hands 7.5% Finger syndactyly 7.5% Hepatosplenomegaly 7.5% Lateral clavicle hook 7.5% Malar flattening 7.5% Nevus flammeus of the forehead 7.5% Phocomelia 7.5% Ptosis 7.5% Scoliosis 7.5% Sensorineural hearing impairment 7.5% Short phalanx of finger 7.5% Strabismus 7.5% Talipes equinovarus 7.5% Tetralogy of Fallot 7.5% Tibial torsion 7.5% Short stature 7% Aplasia of the uterus 5% Axial malrotation of the kidney 5% Cervical ribs 5% Coarctation of aorta 5% Fibular aplasia 5% Fused cervical vertebrae 5% Anteverted nares - Atria septal defect - Autosomal recessive inheritance - Brachycephaly - Carpal synostosis - Decreased antibody level in blood - Horseshoe kidney - Meckel diverticulum - Motor delay - Pancreatic cysts - Seborrheic dermatitis - Seizures - Shoulder muscle hypoplasia - Spina bifida - Ventricular septal defect - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD