|Specialty|| Medical genetics |
Thymic hypoplasia is a condition where the thymus is underdeveloped or involuted.
The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts specifically to foreign invaders. The thymus is composed of two identical lobes and is located anatomically in the anterior superior mediastinum, in front of the heart and behind the sternum. Histologically, each lobe of the thymus can be divided into a central medulla and a peripheral cortex which is surrounded by an outer capsule. The cortex and medulla play different roles in the development of T cells. Cells in the thymus can be divided into thymic stromal cells and cells of hematopoietic origin. Developing T cells are referred to as thymocytes and are of hematopoietic origin. Stromal cells include epithelial cells of the thymic cortex and medulla, and dendritic cells.
Calcium levels can be used to distinguish between the following two conditions associated with thymic hypoplasia:
Calcium is a chemical element with symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx "lime", which was obtained from heating limestone.
Thyme is any member of the genus Thymus of aromatic perennial evergreen herbs in the mint family Lamiaceae. Thymes are relatives of the oregano genus Origanum. They have culinary, medicinal, and ornamental uses, the species most commonly cultivated and used for culinary purposes being Thymus vulgaris.
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone, which is a type of sedimentary rock consisting mainly of calcite) and is the main component of pearls and the shells of marine organisms, snails, and eggs. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It is medicinally used as a calcium supplement or as an antacid, but excessive consumption can be hazardous.
Calcium ions (Ca2+) contribute to the physiology and biochemistry of organisms and the cell. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, in contraction of all muscle cell types, and in fertilization. Many enzymes require calcium ions as a cofactor, those of the blood-clotting cascade being notable examples. Extracellular calcium is also important for maintaining the potential difference across excitable cell membranes, as well as proper bone formation.
Hypocalcaemia is low calcium levels in the blood serum. The normal range is 2.1–2.6 mmol/L with levels less than 2.1 mmol/l defined as hypocalcemia. Mildly low levels that develop slowly often have no symptoms. Otherwise symptoms may include numbness, muscle spasms, seizures, confusion, or cardiac arrest.
Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs either from a disorder within the parathyroid glands or disorder outside the parathyroid glands resulting in them making too much PTH. Most people with primary disease have no symptoms at the time of diagnosis. In those with symptoms the most common is kidney stones with other potential symptoms including weakness, depression, bone pains, confusion, and increased urination. Both types increase the risk of weak bones.
Optic nerve hypoplasia (ONH) is a medical condition arising from the underdevelopment of the optic nerve(s). This condition is the most common congenital optic nerve anomaly. The optic disc appears abnormally small, because not all the optic nerve axons have developed properly. It is often associated with endocrinopathies, developmental delay, and brain malformations. The optic nerve, which is responsible for transmitting visual signals from the retina to the brain, has approximately 1.2 million nerve fibers in the average person. In those diagnosed with ONH, however, there are noticeably fewer nerves.
Hypoplasia is underdevelopment or incomplete development of a tissue or organ. Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells. Hypoplasia is similar to aplasia, but less severe. It is technically not the opposite of hyperplasia. Hypoplasia is a congenital condition, while hyperplasia generally refers to excessive cell growth later in life.
X-linked adrenal hypoplasia congenita is a genetic disorder that mainly affects males. It involves many endocrine tissues in the body, especially the adrenal glands.
Albright's hereditary osteodystrophy is a form of osteodystrophy, and is classified as the phenotype of pseudohypoparathyroidism type 1A; this is a condition in which the body does not respond to parathyroid hormone.
Aplasia is defined in general as "defective development or congenital absence of an organ or tissue." In the field of hematology, the term refers to "incomplete, retarded, or defective development, or cessation of the usual regenerative process."
DAX1 is a nuclear receptor protein that in humans is encoded by the NR0B1 gene. The NR0B1 gene is located on the short (p) arm of the X chromosome between positions 21.3 and 21.2, from base pair 30,082,120 to base pair 30,087,136.
Matrix gla protein (MGP) is member of a family of vitamin-K2 dependent, Gla-containing proteins. MGP has a high affinity binding to calcium ions, similar to other Gla-containing proteins. The protein acts as an inhibitor of vascular mineralization and plays a role in bone organization.
Thymulin is a nonapeptide produced by two distinct epithelial populations in the thymus first described by Bach in 1977. It requires zinc for biological activity. Its peptide sequence is H-Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-OH.
Enamel hypoplasia is a defect of the teeth in which the enamel is deficient in amount, caused by defective enamel matrix formation. Defects are commonly split into one of four categories, pit-form, plane-form, linear-form, and localised enamel hypoplasia. In many cases the enamel crown has pits or a groove on it, and in extreme cases, sections of the tooth have no enamel, exposing the dentin. Enamel hypoplasia varies substantially among populations and can be used to infer health and behaviour in past populations. Defects have also been found in a variety of non-human animals.
Pontocerebellar hypoplasia (PCH) is a heterogeneous group of rare neurodegenerative disorders caused by genetic mutations and characterised by progressive atrophy of various parts of the brain such as the cerebellum or brainstem. Where known, these disorders are inherited in an autosomal recessive fashion. There is no known cure for PCH.
Leydig cell hypoplasia (LCH), also known as Leydig cell agenesis, is a rare autosomal recessive genetic and endocrine syndrome affecting an estimated 1 in 1,000,000 genetic males. It is characterized by an inability of the body to respond to luteinizing hormone (LH), a gonadotropin which is normally responsible for signaling Leydig cells of the testicles to produce testosterone and other androgen sex hormones. The condition manifests itself as pseudohermaphroditism, hypergonadotropic hypogonadism, reduced or absent puberty, and infertility.
Tooth pathology is any condition of the teeth that can be congenital or acquired. Sometimes a congenital tooth diseases are called tooth abnormalities. These are among the most common diseases in humans The prevention, diagnosis, treatment and rehabilitation of these diseases are the base to the dentistry profession, in which are dentists and dental hygienists, and its sub-specialties, such as oral medicine, oral and maxillofacial surgery, and endodontics. Tooth pathology is usually separated from other types of dental issues, including enamel hypoplasia and tooth wear.
|This article about an endocrine, nutritional or metabolic disease is a stub. You can help Wikipedia by expanding it.|