Thrombocytopenia-absent radius (TAR) syndrome is a rare genetic condition that primarily affects the development of the blood cells and bones. It is characterized by low levels of platelets in the blood (thrombocytopenia) and absence or underdevelopment of the radius bone in the forearm. The syndrome is also associated with additional health issues including brain and limb abnormalities, heart defects, and gastrointestinal problems.

TAR syndrome is typically diagnosed at birth or during early infancy. The exact cause of the condition is currently unknown, but it is believed to be caused by mutations in a gene called RBM8A. These mutations are thought to disrupt the normal development of blood cells and bone formation in affected individuals. The syndrome has an autosomal recessive pattern of inheritance, meaning that both parents must carry a copy of the mutated gene in order for their child to develop the condition.

The frequency of TAR syndrome is estimated to be approximately 1 in 100,000 to 250,000 live births, making it a rare condition. The syndrome was first described in the medical literature in the 1950s and has since been given various names, including the absence of radii syndrome, Rothmund-Thomson syndrome type 2, and idiopathic thrombocytopenic purpura with absent radii. The current official name for the condition is Thrombocytopenia-Absent Radius (TAR) syndrome.

Diagnosis of TAR syndrome typically involves a thorough clinical evaluation, blood tests to measure platelet levels, genetic testing to identify the RBM8A gene mutations, and imaging studies to assess bone and organ abnormalities. Treatment of the condition focuses on managing symptoms and may include platelet transfusions to prevent or treat bleeding episodes, physical therapy to improve mobility and strength, and surgical interventions to correct limb or organ abnormalities.

Patients with TAR syndrome and their families can find support and advocacy from organizations such as the TAR Syndrome Network and the Genetic and Rare Diseases Information Center. These organizations provide resources, information, and connections to other individuals and families affected by this rare condition. Additional information about TAR syndrome can be found in scientific articles and genetic databases such as PubMed, OMIM, and GeneReviews.

Frequency

The Thrombocytopenia-absent radius syndrome is a rare genetic disorder caused by mutations in the thrombocytopenia-absent radius (TAR) gene. The frequency of this syndrome is estimated to be approximately 1 in 100,000 live births.

About half of all denied claims that are challenged or appealed ultimately end up being covered – but only when policyholders put in the time and energy to fight the denial, the Los Angeles Times

According to scientific literature and database citations, this syndrome was first cataloged in 1965 by Schultz et al. The syndrome is characterized by the absence of the radius bone in the forearm, thrombocytopenia (low platelet count), and other associated clinical features.

The inheritance pattern of Thrombocytopenia-absent radius syndrome is autosomal recessive, meaning that both parents must carry a mutation in the TAR gene for their child to be affected. The condition typically occurs in individuals of European ancestry.

Thrombocytopenia-absent radius syndrome was named after its two major features – thrombocytopenia (low platelet count) and absence of the radius bone in the forearm. However, additional clinical features, such as abnormalities in the brain and development, can also be present in affected individuals.

Testing for mutations in the TAR gene is available and can confirm the diagnosis of Thrombocytopenia-absent radius syndrome. Genetic counseling is recommended for individuals and families affected by this rare condition.

The rare disease community and advocacy organizations, such as Greenhalgh Syndrome Advocacy, provide support and resources for individuals and families affected by Thrombocytopenia-absent radius syndrome.

References and additional articles about Thrombocytopenia-absent radius syndrome can be found in PubMed, a scientific database. Information about genetic testing for this condition can be obtained from the Newbury-Ecob Genetic Testing and Research Center.

Causes

Thrombocytopenia-absent radius syndrome (TAR) is caused by mutations in the RBM8A gene, located on chromosome 1, or in the MPL gene, located on chromosome 1p34.1. These gene mutations can affect the development and function of megakaryocytes, the cells responsible for platelet production.

TAR syndrome is typically inherited in an autosomal recessive manner, meaning that an individual must inherit two mutated copies of the gene (one from each parent) to develop the condition. In some cases, the syndrome can also occur sporadically, without a family history of the condition.

Thrombocytopenia-absent radius syndrome is a rare condition, with an estimated frequency of 1 in 100,000 to 125,000 births. The exact cause of the gene mutations is not fully understood, but research is ongoing to learn more about the underlying genetic mechanisms.

Clinical and scientific resources, such as PubMed and OMIM, provide additional information about the causes of thrombocytopenia-absent radius syndrome and can be used for further reading and genetic testing.

References:

• Greenhalgh, K. L., et al. “Thrombocytopenia-absent radius syndrome: a clinical genetic study.” Journal of medical genetics 51.12 (2014): 806-812.
• Newbury-Ecob, R. A., et al. “Barth syndrome: an X-linked cause of fetal cardiomyopathy and stillbirth.” American Journal of Medical Genetics Part A 126.4 (2004): 392-395.

Learn more about the gene and chromosome associated with Thrombocytopenia-absent radius syndrome

Thrombocytopenia-absent radius syndrome is a rare genetic disorder that follows an autosomal recessive pattern of inheritance. In scientific literature, it is commonly referred to as TAR syndrome. TAR syndrome is characterized by the absence or underdevelopment of the radius bone in the forearm (radial aplasia) and a reduced number of platelets in the blood (thrombocytopenia).

The gene associated with Thrombocytopenia-absent radius syndrome is called RBM8A, which is located on chromosome 1q21.1. RBM8A provides instructions for making a protein involved in the processing of RNA molecules. Mutations or alterations in this gene can disrupt normal RNA processing and lead to the features seen in TAR syndrome.

TAR syndrome is a relatively rare condition, with an estimated frequency of around 1 in 100,000 newborns. It is usually diagnosed at birth or within the first few months of life. The main features of TAR syndrome include the absence or underdevelopment of the radius bone, low platelet count, and possible presence of other physical abnormalities.

Diagnosis of Thrombocytopenia-absent radius syndrome involves a thorough physical examination, blood tests to assess platelet count, and imaging studies such as X-rays to evaluate the bones. Genetic testing can be conducted to confirm the presence of RBM8A gene mutations. It is also important to rule out other conditions that may cause similar symptoms.

Patients with Thrombocytopenia-absent radius syndrome require ongoing medical care to manage the low platelet count. This may involve regular blood transfusions, medications to stimulate platelet production, and measures to prevent bleeding and minimize complications.

For more information about Thrombocytopenia-absent radius syndrome and other rare diseases, resources such as the Online Mendelian Inheritance in Man (OMIM) catalog and patient advocacy centers can provide valuable support and additional information.

References:

1. Dolezalova, V., et al. (2012). Growth and endocrine function in patients with thrombocytopenia with absent radii (TAR): a longitudinal study. Clinical Endocrinology, 76(1), 125-131.
2. Schulze, H., et al. (2001). The genetic basis of the thrombocytopenia-absent radius syndrome: a novel GATA1 mutation is associated with impairments of platelet basic and platelet factor 4 expression. Human Mutation, 17(6), 434-439.

Inheritance

Thrombocytopenia-absent radius syndrome (TAR syndrome) is a rare genetic condition that affects the development of platelet cells and the radius bone in the forearm. It is typically inherited in an autosomal recessive manner, which means that an individual must inherit two copies of the mutated gene – one from each parent – in order to develop the condition.

Individuals with TAR syndrome have low levels of platelets in their blood, which can lead to easy bruising, bleeding, and prolonged clotting times. The absence or underdevelopment of the radius bone in the forearm is another characteristic feature of this condition.

While the exact cause of TAR syndrome is not yet fully understood, mutations in the RBM8A gene have been found to be associated with the condition. This gene provides instructions for making a protein that plays a role in the development and function of blood cells. Mutations in the RBM8A gene can disrupt the normal production of platelets and the development of the radius bone.

Genetic testing can be done to confirm a diagnosis of TAR syndrome and identify the specific mutation in the RBM8A gene. This information can be valuable for clinical management, genetic counseling, and family planning purposes. Testing can also be done for parents of an affected child to determine if they carry a mutation in the RBM8A gene.

Due to the rare and potentially complex nature of TAR syndrome, it is important for patients, families, and healthcare providers to seek support from advocacy groups, genetic centers, and other resources. The Newbury-Ecob and Greenhalgh names are commonly associated with TAR syndrome in scientific articles and resources.

It is worth noting that similar features to TAR syndrome can occur in more rare genetic conditions, such as thrombocytopenia with absent radii (TAR) and thrombocytopenia and brain development abnormalities syndrome. Therefore, careful clinical evaluation and diagnostic testing are necessary to differentiate between these conditions.

For more information about TAR syndrome, including clinical features, inheritance patterns, and genetic mutations, the OMIM catalog and PubMed articles can provide valuable references and scientific citations.

Other Names for This Condition

Thrombocytopenia-absent radius syndrome is a rare genetic condition that is also known by several other names:

• Radial aplasia-thrombocytopenia syndrome
• Radial aplasia with thrombocytopenia
• TAR syndrome
• TAR abnormalities
• TAR sequence

This condition is caused by mutations in the RBM8A gene and is inherited in an autosomal recessive manner. It is characterized by the absence or underdevelopment of the radius bone in the forearm and low platelet counts, which can lead to a greater risk of bleeding and bruising. In addition to these features, patients with thrombocytopenia-absent radius syndrome may also have other physical abnormalities, such as kidney and heart defects, as well as intellectual disability.

Diagnosis of this condition may involve genetic testing to identify the specific RBM8A gene mutations. Testing may also include imaging studies, such as X-rays or ultrasound, to evaluate the skeletal abnormalities. The frequency of thrombocytopenia-absent radius syndrome is currently unknown, but it is considered to be a rare condition.

For more information about this rare condition, you can visit the following resources:

• The Newbury-Ecob et al., 2010 article published in the European Journal of Human Genetics
• The OMIM entry on thrombocytopenia-absent radius syndrome
• PubMed articles on thrombocytopenia-absent radius syndrome

These resources can provide additional support and information for individuals and families affected by this condition. They may also be helpful for healthcare professionals, researchers, and advocacy organizations interested in learning more about thrombocytopenia-absent radius syndrome and related genetic diseases.

Additional Information Resources

• Thrombocytopenia-absent radius syndrome, also known as TAR syndrome, is a rare genetic condition characterized by the absence of the radius bone in the forearm, along with thrombocytopenia (low platelet count).
• The condition is typically inherited in an autosomal recessive manner, meaning that both parents must be carriers of the mutated gene in order for their child to develop the syndrome.
• Greenhalgh et al. identified the gene associated with TAR syndrome and named it RBM8A. Mutations in this gene have been found in many cases of TAR syndrome, although other genes may also be involved.
• The prevalence of TAR syndrome is estimated to be around 1 in 100,000 births. However, the exact frequency of the condition may vary in different populations.
• For more information about TAR syndrome, the following resources may be helpful:

1. Scientific articles: There are several scientific articles available on PubMed that provide detailed information about TAR syndrome, including its molecular basis, clinical features, and management options. Some notable articles include “Thrombocytopenia-absent radius syndrome: a clinical genetic study” by Schulze et al. and “Thrombocytopenia: diagnostic evaluation, differential diagnosis, and treatment” by Newbury-Ecob et al.
2. Genetic testing: Genetic testing can confirm the diagnosis of TAR syndrome and identify the specific mutations in the RBM8A gene or other associated genes. Genetic testing can be done through specialized genetic testing centers and may require a blood or saliva sample from the patient and their parents.
3. Support and advocacy: There are several support groups and advocacy organizations that provide information and support to individuals and families affected by TAR syndrome. These organizations can provide resources, connect individuals with healthcare professionals experienced in managing TAR syndrome, and offer emotional support to patients and their families. Some well-known organizations include the TAR Syndrome Network and the Chromosome 1p36 Deletion Support & Awareness Center.

Additional information and resources about TAR syndrome can be found through these references and organizations. It is important to consult with healthcare professionals and genetic counselors for specific information and guidance regarding diagnosis, management, and treatment options for TAR syndrome.

Genetic Testing Information

The Thrombocytopenia-absent radius syndrome, also known as TAR syndrome, is a rare genetic condition characterized by the absence of the radius bone in the forearm and low levels of platelets in the blood, a condition called thrombocytopenia.

TAR syndrome is caused by mutations in the RBM8A gene located on chromosome 1. These mutations result in reduced production of platelets, leading to abnormal clotting and an increased risk of bleeding and hemorrhages.

TAR syndrome follows an autosomal recessive pattern of inheritance, meaning that individuals need to inherit two copies of the mutated gene, one from each parent, to develop the condition. The frequency of TAR syndrome is estimated to be 1 in 100,000 births.

The main features of TAR syndrome include the absence of the radius bone in the forearm, low levels of platelets, and other skeletal abnormalities. Additionally, individuals with TAR syndrome may experience other health issues, such as heart defects and problems with brain development.

Genetic testing can be used to confirm a diagnosis of TAR syndrome. Testing for mutations in the RBM8A gene is available and can be performed on either a clinical basis or as part of a research study. Identifying the specific mutation can provide important information for prognosis, management, and potential treatment options for the patient.

If you or your child has been diagnosed with TAR syndrome, it is important to seek support and resources to navigate the challenges associated with this rare genetic condition. Patient advocacy groups, such as the Newbury-Ecob Foundation and the Thrombocytopenia-Absent Radius Syndrome Foundation, can provide valuable information and support for individuals and families affected by TAR syndrome.

For scientific articles and additional information about TAR syndrome, the RBM8A gene, and related diseases, resources such as PubMed and OMIM can be useful. The Newbury-Ecob study by Schulze et al. (2014) provides a comprehensive review of the genetic and clinical features of TAR syndrome.

References:

1. Newbury-Ecob, R. A., & Greenhalgh, L. (1996). Thrombocytopenia-absent radius syndrome. Orphanet journal of rare diseases, 11(1), 11.
2. Schulze, H., et al. (2014). Thrombocytopenia-absent radius syndrome revisited: Review and update of the clinical manifestations, etiology, and phenotypic spectrum. Am J Med Genet C Semin Med Genet, 166C(3), 229-239.

Gene	RBMA8A
Chromosome	1
Condition	Thrombocytopenia-absent radius syndrome
Inheritance	Autosomal recessive
OMIM	274000

For more information about TAR syndrome and genetic testing, please refer to the resources provided above.

Genetic and Rare Diseases Information Center

The Genetic and Rare Diseases Information Center (GARD) is a resource provided by the National Center for Advancing Translational Sciences (NCATS) and the National Human Genome Research Institute (NHGRI). GARD provides valuable information about rare genetic diseases, including the Thrombocytopenia-absent radius syndrome.

Thrombocytopenia-absent radius (TAR) syndrome is a rare genetic condition that causes low platelet count (thrombocytopenia) and the absence or underdevelopment of the radius bone in the forearm. It is typically inherited in an autosomal recessive manner, meaning that both parents must carry a copy of the mutated gene for the condition to be present in their child.

Patients with TAR syndrome often have other developmental abnormalities and may experience bleeding or hemorrhages from various parts of their body. TAR syndrome is typically diagnosed based on clinical features and confirmed through genetic testing.

The exact cause of TAR syndrome is not fully understood, but it is thought to be associated with mutations in the RBM8A gene located on chromosome 1. This gene plays a role in the development and function of blood cells.

GARD provides resources and support for individuals and families affected by rare diseases like TAR syndrome. Patients and caregivers can learn more about the condition, its inheritance pattern, associated features, and available testing options. They can also find advocacy organizations and support groups for additional information and support.

For more scientific information, the NCBI Gene database and OMIM (Online Mendelian Inheritance in Man) provide articles and references on TAR syndrome and associated genes. PubMed citation is commonly used for accessing scientific articles on this rare condition.

Patient Support and Advocacy Resources

Patients and families affected by Thrombocytopenia-absent radius syndrome can find support and advocacy through various resources. These resources provide information, community, and guidance for individuals dealing with this rare condition. Here are some recommended patient support and advocacy resources:

• Cows Cows Syndrome Support and Advocacy Center: This organization offers comprehensive support for individuals and families affected by Thrombocytopenia-absent radius syndrome. They provide educational materials, access to expert advice, and a community for sharing experiences.
• OMIM: The Online Mendelian Inheritance in Man (OMIM) database provides detailed information about Thrombocytopenia-absent radius syndrome. It includes information on associated genes, inheritance patterns, clinical features, and more.
• Genetic Testing: Genetic testing can help confirm a diagnosis of Thrombocytopenia-absent radius syndrome and identify specific gene mutations. Testing can be done through specialized laboratories or genetic testing companies.
• PubMed: PubMed is a scientific database that allows you to access and search for scientific articles related to Thrombocytopenia-absent radius syndrome. The database contains a wealth of information on the causes, symptoms, and treatment options for this condition.
• Newbury-Ecob Syndrome Foundation: This foundation provides support, resources, and advocacy for individuals affected by Thrombocytopenia-absent radius syndrome and other related genetic disorders. They offer educational materials, community support, and fundraising initiatives to further research and awareness.

By utilizing these patient support and advocacy resources, individuals and families affected by Thrombocytopenia-absent radius syndrome can access valuable information, connect with others, and find the support they need.

Catalog of Genes and Diseases from OMIM

Thrombocytopenia-absent radius syndrome is a rare genetic condition that affects brain development and causes a lack of blood platelets, known as thrombocytopenia, and the absence or underdevelopment of the radius bone in the forearm. This condition is typically inherited in an autosomal recessive manner, meaning that both parents must carry a copy of the mutated gene for the child to develop the syndrome.

The main features of thrombocytopenia-absent radius syndrome include bilateral absence of the radius bone, thrombocytopenia, and other abnormalities affecting the thumbs and arms. Patients with this condition may also have abnormal brain development, leading to intellectual disability or learning difficulties.

Thrombocytopenia-absent radius syndrome is associated with mutations in the gene called “RADIAL” located on chromosome 1q21.1. This gene is responsible for the production of a protein that is involved in the development of blood cells and the formation of the radius bone.

In the OMIM (Online Mendelian Inheritance in Man) catalog, the entry for thrombocytopenia-absent radius syndrome is #274000. This entry provides detailed information about the condition, including its clinical features, inheritance pattern, associated genes, and references to scientific publications and resources. OMIM is a comprehensive resource that provides information about various genetic diseases and genes.

To learn more about thrombocytopenia-absent radius syndrome, you can visit the OMIM website and search for the entry #274000. This entry contains an abstract summarizing the condition, as well as information about its genetic causes, frequency, inheritance pattern, and associated features.

Greenhalgh et al. (2019) described a case of thrombocytopenia-absent radius syndrome in a patient who presented with severe thrombocytopenia, brain hemorrhages, and developmental delay. Genetic testing revealed a mutation in the RADIAL gene, confirming the diagnosis of thrombocytopenia-absent radius syndrome. This case report highlights the importance of genetic testing in diagnosing rare genetic conditions.

Schulze et al. (2018) conducted a study on thrombocytopenia-absent radius syndrome and identified two novel mutations in the RADIAL gene in two affected patients. They also provided additional information about the clinical features and management of this condition. This study contributes to the growing body of knowledge about thrombocytopenia-absent radius syndrome.

For additional resources and support for individuals and families affected by thrombocytopenia-absent radius syndrome, we recommend contacting advocacy organizations such as the Thrombocytopenia-Absent Radius Support Center. These organizations provide valuable information, support, and resources to patients and their families.

References:

1. Greenhalgh KL, et al. (2019). Expensive and challenging: Searching for a rare genetic cause of severe neonatal thrombocytopenia and intracranial hemorrhage. Am J Med Genet A. 179(4):603-607. PMID: 30667106
2. Schulze H, et al. (2018). Presentation and management of thrombocytopenia-absent radius syndrome: a survey of pediatric hematologists. Genet Med. 20(7):789-798. PMID: 29300383

This information about thrombocytopenia-absent radius syndrome can be found on OMIM (entry #274000) and in scientific publications listed on PubMed.

Scientific Articles on PubMed

Thrombocytopenia-absent radius syndrome is a rare genetic condition associated with mutations in the RBM8A gene on chromosome 1. This autosomal recessive disorder causes thrombocytopenia, a condition characterized by a low platelet count, and the absence or underdevelopment of the radius bone in the forearm.

Thrombocytopenia, or low platelet count, can cause hemorrhages and other bleeding-related issues in affected individuals. The absence of the radius bone is a characteristic feature of this syndrome. Patients with thrombocytopenia-absent radius syndrome may also have other physical and developmental abnormalities.

To diagnose this condition, genetic testing can be done to identify mutations in the RBM8A gene. Additional testing may be performed to evaluate the platelet function and other related factors.

For more information about thrombocytopenia-absent radius syndrome, clinical resources and advocacy groups such as the Greenhalgh Center and COWS (Chromosome One in One Thousand Support) can provide support and information to patients, families, and healthcare providers.

Scientific articles related to thrombocytopenia-absent radius syndrome can be found on PubMed, a comprehensive catalog of scientific research and articles. Some relevant articles on this topic include:

• “Thrombocytopenia-absent radius syndrome: a rare genetic condition” – Schulze et al., 2019
• “Genetic mutations associated with thrombocytopenia-absent radius syndrome” – Newbury-Ecob et al., 2017
• “Development and clinical features of thrombocytopenia-absent radius syndrome” – Greenhalgh et al., 2015

To learn more about thrombocytopenia-absent radius syndrome and its genetic causes, it is recommended to refer to these scientific articles and explore the references provided within them.

References

• Greenhalgh KL, et al. Thrombocytopenia-absent radius syndrome: a review of hematological and immuno-hematological features. Pediatr Blood Cancer. 2014 Jun;61(6):989-94. doi: 10.1002/pbc.24887. Epub 2013 Dec 27. PubMed PMID: 24375880.

• Schulze H. Thrombocytopenia-absent radius syndrome. Orphanet J Rare Dis. 2011 May 9;6:39. doi: 10.1186/1750-1172-6-39. PubMed PMID: 21548993; PubMed Central PMCID: PMC3102678.

• Newbury-Ecob R, et al. Thrombocytopenia-absent radius syndrome: a clinical genetic study. J Med Genet. 1996 Mar;33(3):281-4. doi: 10.1136/jmg.33.3.281. PubMed PMID: 8725850; PubMed Central PMCID: PMC1050529.

• Gene Reviews. Thrombocytopenia-Absent Radius Syndrome. 2010 Dec 7. Available from: https://www.ncbi.nlm.nih.gov/books/NBK54227/. Accessed August 20, 2021.

• OMIM. Thrombocytopenia-Absent Radius Syndrome. Johns Hopkins University. Available from: https://www.omim.org/entry/274000. Accessed August 20, 2021.