Diseases

Thrombocytopenia- cyclic

Cyclic thrombocytopenia (medical condition): A rare disorder characterized by periodic fluctuations in blood platelet levels.

Thrombocytopenia-absent radius (TAR) syndrome

is a rare condition in which thrombocytopenia is associated with bilateral radial aplasia. TAR syndrome was first described in 1951. An autosomal recessive inheritance pattern was proposed because TAR affected more than one member of some families. In 1969, TAR was defined as a syndrome and further classified as the association of hypomegakaryocytic thrombocytopenia and absent radii. The expression varies and includes abnormalities in the GI, skeletal, hematologic, and cardiac systems. 

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Thrombomodulin anomalies- familial

A defect in a protein involved with anticoagulation which results in an increased risk of developing blood clots which can result in death.

Thrombotic thrombocytopenic purpura- acquired

Thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder. In TTP, blood clots form in small blood vessels throughout the body.

The clots can limit or block the flow of oxygen-rich blood to the body's organs, such as the brain, kidneys, and heart. As a result, serious health problems can develop.

The increased clotting that occurs in TTP also uses up platelets (PLATE-lets) in the blood. Platelets are blood cell fragments that help form blood clots. These cell fragments stick together to seal small cuts and breaks on blood vessel walls and stop bleeding.

With fewer platelets available in the blood, bleeding problems can occur. People who have TTP may bleed inside their bodies, underneath the skin, or from the surface of the skin. When cut or injured, they also may bleed longer than normal.

"Thrombotic" (throm-BOT-ik) refers to the blood clots that form. "Thrombocytopenic" (throm-bo-cy-toe-PEE-nick) means the blood has a lower than normal number of platelets. "Purpura" (PURR-purr-ah) refers to purple bruises caused by bleeding under the skin.

Bleeding under the skin also can cause tiny red or purple dots on the skin. These pinpoint-sized dots are called petechiae (peh-TEE-kee-ay). Petechiae may look like a rash.

TTP also can cause red blood cells to break apart faster than the body can replace them. This leads to hemolytic anemia (HEE-moh-lit-ick uh-NEE-me-uh)—a rare form of anemia. Anemia is a condition in which the body has a lower than normal number of red blood cells.

A lack of activity in the ADAMTS13 enzyme (a type of protein in the blood) causes TTP. The ADAMTS13 gene controls the enzyme, which is involved in blood clotting. The enzyme breaks up a large protein called von Willebrand factor that clumps together with platelets to form blood clots.

Types of Thrombotic Thrombocytopenic Purpura

The two main types of TTP are inherited and acquired. "Inherited" means the condition is passed from parents to children through genes. This type of TTP mainly affects newborns and children.

In inherited TTP, the ADAMTS13 gene is faulty and doesn't prompt the body to make a normal ADAMTS13 enzyme. As a result, enzyme activity is lacking or changed.

Acquired TTP is the more common type of the disorder. "Acquired" means you aren't born with the disorder, but you develop it. This type of TTP mostly occurs in adults, but it can affect children.

In acquired TTP, the ADAMTS13 gene isn't faulty. Instead, the body makes antibodies (proteins) that block the activity of the ADAMTS13 enzyme.

It's not clear what triggers inherited and acquired TTP, but some factors may play a role. These factors may include:

  • Some diseases and conditions, such as pregnancy, cancer, HIV, lupus, and infections

  • Some medical procedures, such as surgery and blood and marrow stem cell transplant

  • Some medicines, such as chemotherapy, ticlopidine, clopidogrel, cyclosporine A, and hormone therapy and estrogens

  • Quinine, which is a substance often found in tonic water and nutritional health products

Thymic Carcinoma

Thymic carcinoma, or type C thymoma, is a malignancy of the thymus. It is a rare cancer that is often diagnosed at advanced stages. Recurrence following treatment is common, and thymic carcinoma is associated with a poor prognosis.

A study examining cases of thymic carcinoma in the United States from 2001 to 2015 found a peak incidence from 70 to 74 years old and a higher incidence in males compared to females. After thymoma, thymic carcinoma is the second most common type of thymus cancer

Thymidine Kinase 2 Deficiency

Thymidine kinase 2 deficiency (TK2D) is a rare genetic mitochondrial disorder causing progressive muscle weakness (myopathy) that can lead to severe breathing, swallowing, and walking difficulties. It is caused by mutations in the TK2 gene, which disrupts the production of mitochondrial DNA (mtDNA) and impairs energy production in cells, particularly muscles. Symptoms range from mild to severe and can appear at any age, with earlier onset typically resulting in more rapid progression. 

Thyroid cancer- anaplastic

Anaplastic thyroid cancer (ATC) (or undifferentiated) is a form of thyroid cancer which has a very poor prognosis (14% ten-year survival rate) due to its aggressive behavior and resistance to cancer treatments.

Thyroid cancer- familial medullary

Medullary thyroid cancer is completely different than the more common papillary and follicular types. Medullary thyroid cancer is usually not classified in terms of differentiation because it does not arise from the thyroid cells themselves, but rather from the specialized "C-cells" that are in between the thyroid cells. These C-cells are also sometimes referred to as parafollicular cells. They are found mostly in the upper and middle parts of the thyroid and they produce a substance called calcitonin which can serve as a marker for medullary thyroid cancer. Although we know that calcitonin is somehow involved in the body's regulation of calcium, we do not know its exact function. We do know that people who have had their thyroids removed surgically, do not require replacement of calcitonin for normal function and a healthy life.

Thyroid cancer- follicular

Follicular thyroid cancer is a form of thyroid cancer which occurs more commonly in women of over 50 years old. Thyroglobulin (Tg) can be used as a tumor marker for well-differentiated follicular thyroid cancer. About 33,500 Americans are diagnosed with thyroid cancer each year, with incidence rates increasing by about 11 percent asnnually. Follicular Thyroid Cancer makes up about 15 percent of these cases. Follicular Thyroid Cancer begins in the follicular cells and grows slowly; it can be treated successfully if diagnosed at an early stage. About 1,500 Americans die from all types of thyroid cancer each year. This relatively low death rate is due to successful early detection and treatment in most cases.

Thyroid cancer- Hurthle cell

A rare form of cancer that originates in the thyroid gland. This cancer is characterized by the abnormal presence of Hurthle cells which may signify benign or malignant thyroid cancer. The cancer usually responds well to treatment if detected in the earlier stages.

Thyroid carcinoma

Carcinoma of the thyroid gland is an uncommon cancer but is the most common malignancy of the endocrine system. 

Thyroid Eye Disease

Thyroid eye disease (TED) is characterized by progressive inflammation and damage to tissues around the eyes, especially extraocular muscle, connective and fatty tissue. TED has an active disease phase in which progressive inflammation, swelling and tissue changes occur. This phase is associated with a variety of symptoms including pain, a gritty feeling in the eyes, swelling or abnormal positioning of the eyelids, watery eyes, bulging eyes (proptosis) and double vision (diplopia). The active phase can last anywhere from approximately 6 months to 2 years. This is followed by an inactive phase in which the disease progression has stopped. However, some symptoms such as double vision and bulging eyes can remain. In some people, cosmetic changes and significant disability can develop. Although uncommon, in severe instances, vision loss can occur. Thyroid eye disease is an autoimmune disorder. An autoimmune disorder is one in which the body’s adaptive immune system, which protects the body from infectious or other foreign substances, mistakenly attacks healthy tissue instead. Treatment includes reversing hyperthyroidism, specific medications, supportive measures and in some patients, surgery.

Thyroid eye disease most commonly occurs as part of Graves’ disease, which is an autoimmune disease that affects the thyroid and often the skin and eyes. The thyroid is a butterfly-shaped gland located at the base of the neck. The thyroid is part of the endocrine system, the network of glands that secrete hormones that regulate the chemical processes (metabolism) that influence the body’s activities as well as regulating the heart rate, body temperature and blood pressure. Graves’ disease is characterized by abnormal enlargement of the thyroid (goiter) and increased secretion of thyroid hormone (hyperthyroidism). Less often, thyroid eye disease can occur in people who have or have had an overactive thyroid (hyperthyroidism) or in individuals with an underactive thyroid (hypothyroidism) such as people who have a disorder called Hashimoto thyroiditis.

Although relatively infrequent, TED does not currently fulfill the main criterion for being defined as a rare disease, but several variants of the disease are considered rare diseases

Thyroid hormone plasma membrane transport defect

Thyroid problems caused by a defect in the transport of a thyroid hormone called T4 (thyroxine) within the body. The thyroid produces excessive hormones to try to compensate for that inability of the body to utilize the hormone.

Tibial aplasia ectrodactyly

A rare genetic disorder characterized by split hands and/or feet and absence of long bones of the arms or legs

Tick paralysis

Tick paralysis is the only tick-borne disease that is not caused by an infectious organism. The illness is caused by a neurotoxin produced in the tick's salivary gland. After prolonged attachment, the engorged tick transmits the toxin to its host. The incidence of tick paralysis is unknown.

Tick-borne encephalitis

A viral infection (flavivirdae) of the central nervous system which is transmitted by ticks. Ticks usually feed on small rodents who are the main carriers of the virus. Transmission may also occur through the consumption of untreated milk. The incubation period is usually 1 to 2 weeks. The symptoms occur in two phases: the first involves symptoms of a general viral illness (fever, headache, nausea, aching muscles) followed by a period of remission and then central nervous system inflammation such as meningitis. However, many patients only suffer the first phase of the disease.

Tièche-Jadassohn nevus

A rare genetic disorder characterized by characteristic blue, slightly raised, sharply defined skin growths. The lesions can vary in size.

Tietz syndrome

Tietz syndrome is a condition characterized by deafness and albinism. (Tietz syndrome is not to be confused with Tietze's syndrome, which is a benign inflammation of the cartilages connecting to the sternum or ribs.)

Tietze syndrome

A rare disorder characterized by inflammation, swelling, redness and tenderness of the rib cartilage (costochondrial cartilage) in the upper chest. The condition causes pain and can last from hours to weeks. The cause of the condition is unknown. Also called Tietze's syndrome.

Tiglic acidemia

Tiglic acidemia: Increased blood tiglic acid levels due to a metabolic disorder involving the breakdown of isoleucine to propionic acid.

Timothy syndrome

Timothy syndrome is a rare autosomal dominant disorder characterized by physical malformations, as well as neurological and developmental defects, including heart QT-prolongation, heart arrhythmias, structural heart defects, syndactyly (webbing of fingers and toes) and autism spectrum disorders. Timothy syndrome often ends in early death.

Togaviridae disease

Togaviridae disease: Infection with any of a number of togaviridae viruses which can caused conditions such as Equine encephalitis, Ross River virus and Rubella virus. Symptoms are determined by the type of virus involved. Togaviridae are arboviruses and are transmitted by arthropods.