TAR syndrome

Under the TAR syndrome, English Thrombocytopenia-Absent Radius Syndrome, medicine understands a malformation syndrome, the main symptoms of which include the failure of the spokes and thrombocytopenia. The cause of the syndrome is believed to be an inherited gene mutation. Treatment in the first few years of life mainly consists of platelet transfusion.

What is TAR Syndrome?

The TAR syndrome is a complex of multiple malformations that manifests itself in newborns. The main symptoms of the hereditary malformation syndrome are a bilateral failure of the spoke and a lack of blood platelets. Because of the symptoms, the syndrome is sometimes dated Radial aplasia-thrombocytopenia syndrome the speech. The TAR syndrome has so far been described in a little over 100 cases. The exact prevalence is not known, but the symptom complex is considered to be relatively rare.

The syndrome was first described in 1929. The Americans H. M. Greenwald and J. Sherman are considered to be the first to describe it. According to the previous documentation, women are slightly more likely to be affected by malformations than men. Because of its rarity, the syndrome has not been fully researched. The research into the causes has delivered partial successes, but has not yet been able to provide a sufficient explanation for the whole complex.

causes

In 2007, a possible cause for TAR syndrome was identified that corresponds to a genetic mutation. Partial symptoms of the complex are caused by a microdeletion on chromosome 1 in the gene locus q21.1. In this context, we are talking about the 1q21.1 deletion syndrome. Chromosome 1 has so far been associated with numerous hereditary diseases.

Mutations in this gene location can trigger Usher syndrome, Gaucher's disease or Alzheimer's disease, for example. Chromosome 1 is present as a chromosome pair in all body cells and corresponds to the largest human chromosome. The mutation associated with TAR syndrome seems to necessarily be present in all patients. However, the mutation does not adequately explain the individual symptoms of the syndrome.

The TAR syndrome is considered a hereditary disease. Familial accumulation was observed in the cases documented so far. Heredity appears to be an autosomal recessive inheritance and to take place with a relatively large variability in manifestation.

Symptoms, ailments & signs

All patients with TAR syndrome have thrombocytopenia. The lack of platelets leads to an increased tendency to bleed. They decline particularly in the first two years of life. In the first few months, intracranial bleeding can occur, which can lead to motor or mental retardation. Bilaterally, all patients with the syndrome also lack spokes.

The affected person's thumb is there, but it only functions abnormally. Often there is a radial deviation of the hand, which manifests itself as a club hand deformity. The ulna of all TAR patients is shortened and partially bent. About a third of the patients lack the humerus, which is usually also shortened and has a dysplastic effect. The joints of the elbow, shoulder and hand are restricted in their mobility.

In some cases there are also changes in the blood. In two thirds of the cases, there are greatly increased leukocytes. Often there is a cow's milk allergy or intolerance that promotes diarrhea or exacerbates thrombocytopenia. In about half of all patients, the symptoms are associated with dysplasia of the lower extremities.

In particular, hip dysplasia, coxa valga, knee joint subluxation or patellar dysplasia with dislocation are common symptoms. The knee may be stiffened. The positions of the feet and toes are often abnormal. Many of those affected also suffer from short stature or a heart defect in the sense of a Fallot tetralogy or an atrial septal defect. The eye often has ptosis or glaucoma.

Diagnosis & course of disease

In the first months of life, the doctor will observe a tendency to bleeding and thrombocytopenia in TAR patients, which he must differentiate from Fanconi anemia in a differential diagnosis. In X-ray imaging, the TAR syndrome is particularly evident in the non-alignment of the spokes on both sides and the resulting misalignments.

In terms of differential diagnosis, the Holt-Oram syndrome and Roberts syndrome must also be considered. As soon as the first two years of life have passed, the prognosis for patients with TAR syndrome is rather favorable. In individual cases, the prognosis is based on accompanying symptoms such as the heart defect.

Complications

Various malformations occur in TAR syndrome. First and foremost, the malformations lead to a significantly increased tendency to bleed. Those affected suffer from severe bleeding, even with very slight and minor injuries, which cannot be stopped easily. Bleeding often occurs on the gums or in the nose and has a very negative effect on the quality of life of the person concerned.

Furthermore, mental retardation can occur due to the TAR syndrome. Patients very often depend on the help of other people in their lives and cannot do many everyday things on their own. The mobility of the shoulders and hands is also significantly restricted by the syndrome, as the humerus is missing. Furthermore, it can lead to a heart defect or discomfort to the eyes.

The syndrome is usually associated with decreased life expectancy. The parents or relatives also often suffer from psychological complaints or depression. Symptomatic treatment of TAR syndrome usually does not involve complications. Unfortunately, not all complaints can be completely restricted.

When should you go to the doctor?

In most cases, with TAR syndrome, the person affected will need medical evaluation and treatment. There can be no independent healing, so that the person affected with this disease is always dependent on a medical diagnosis. The earlier the syndrome is recognized, the better the further course of the disease will usually be. Since it is a hereditary disease, no complete cure can take place. If the person affected by the syndrome wishes to have children, genetic counseling can also be used.

In the case of TAR syndrome, a doctor should be consulted if the person concerned suffers from severe mental retardation. As a rule, the patients are dependent on the help of others in their lives. The mobility of the person affected can also be restricted by the TAR syndrome, so that a visit to a doctor is necessary. It is not uncommon for the internal organs to be affected by various defects. The diagnosis of TAR syndrome can be made by a general practitioner or pediatrician. For further treatment, a visit to a specialist is necessary.

Therapy & Treatment

The TAR syndrome cannot be treated either causally or specifically. So far, only symptomatic treatments are available. The malformations cannot be corrected in the first few years of life due to the tendency to bleed. In later stages of life, reconstructive surgical interventions can correct the missing spokes and multiple malpositions. It is essential to prevent all bleeding or hemorrhages in the first years of life.

The aim of the initial therapy is above all to reduce the significant consequences of the disease. Severe thrombocytopenias in the first few years of life call for platelet transfusions. In and of itself, there is no motor developmental disorder. Neurological limitations are also rare. The mental development is inconspicuous. All retardations are thus at best a consequence of intracranial bleeding, which must be prevented by the transfusions.

When the thrombocytopenia has subsided, plastic surgical treatment is done. These measures are accompanied by [[[Physiotherapy physiotherapeutic treatment steps]], which are intended to ensure perfect motor development. In adulthood, patients are often no longer dependent on any treatment measures and lead a largely normal life with an unrestricted quality of life.

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prevention

The definitive causes of the TAR syndrome have not yet been clarified. For this reason, the syndrome cannot yet be prevented. However, everything indicates that genetic factors play a role in the syndrome. Therefore, genetic counseling for those affected can largely be described as a preventive measure.

Aftercare

Follow-up care for TAR syndrome depends on the type and severity of the malformations. After a surgical procedure, which is an option for minor malformations, the patient needs extensive follow-up care. In the event of acute bleeding, immediate care at the clinic is necessary. The patient then needs a few days of rest.

A final follow-up examination aims to determine the further treatment measures. People who suffer from TAR syndrome must consult their doctor regularly to clarify their current state of health. Medical complications are not always apparent to the patient, especially with internal bleeding. In the case of severe thrombopenia, a blood transfusion may be necessary, which is carried out in the clinic and which is usually associated with a debriefing.

The patient in turn needs rest and protection. Hospitalization is usually indicated. Patients suffering from TAR syndrome need a specialist doctor. The doctor responsible is usually the internist or the general practitioner who is already involved in the treatment. Long-term hospitalization makes sense for chronic complaints. The patient should also get in touch with a physiotherapist and other specialists. Psychological support for the patient may also be necessary.

You can do that yourself

TAR syndrome can only be treated symptomatically. The patient must pay attention to warning signs and inform the doctor so that a blood transfusion can be performed early. After such a transfusion, the body is weakened and it is important to ensure a balanced diet that supports the body in producing blood.

After surgical treatment of the malformations, rest and bed rest apply. The patient must care for the wounds as directed by the doctor to avoid inflammation and other complications. In the case of malformations in the limbs, physiotherapeutic treatment may also be necessary. Affected people can do physiotherapy at home and improve the coordination of the affected limbs with regular exercise.

If these measures do not achieve the desired result, the doctor must be consulted. Since TAR syndrome is an extremely rare condition, a specialist doctor has to take over the therapy. It is advisable to search Internet forums for other sufferers, as there are only a few self-help groups for the condition. Finally, it is important to make the necessary visits to the doctor in order to avoid serious complications. TAR syndrome must be closely monitored due to any blood transfusions.