A calcified mass that can occur in soft tissue or muscle following a trauma to the area. The trauma may result from such things as mechanical injury or tendonitis. The symptoms are determined by the location and size of the lesion.
A very rare progressive disorder involving calcification of muscles, tendons and ligaments
Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body fat and increased muscle size. Affected individuals have up to twice the usual amount of muscle mass in their bodies. They also tend to have increased muscle strength. Myostatin-related muscle hypertrophy is not known to cause any medical problems, and affected individuals are intellectually normal.
Myotilinopathy is one of the intermediate filament human disorders associated with mutations in the myotilin gene (MYOT). Myolinopathies include autosomal dominant limb girdle muscular dystrophy type 1A (LGMD1A) and a subgroup of myofibrillar myopathy (MFM) associated with myotilin mutations (MFM/MYOT).
Myotonic dystrophy is an inherited disorder in which the muscles contract but have decreasing power to relax. With this condition, the muscles also become weak and waste away. (Source: Genes and Disease by the National Center for Biotechnology)
Myotonia congenita is a disorder that affects muscles used for movement (skeletal muscles). Beginning in childhood, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. Although myotonia can affect any skeletal muscles, including muscles of the face and tongue, it occurs most often in the legs. Myotonia causes muscle stiffness that can interfere with movement. In some people the stiffness is very mild, while in other cases it may be severe enough to interfere with walking, running, and other activities of daily life. These muscle problems are particularly noticeable during movement following a period of rest. Many affected individuals find that repeated movements can temporarily alleviate their muscle stiffness, a phenomenon known as the warm-up effect.
The two major types of myotonia congenita are known as Thomsen disease and Becker disease. These conditions are distinguished by the severity of their symptoms and their patterns of inheritance. Becker disease usually appears later in childhood than Thomsen disease and causes more severe muscle stiffness, particularly in males. People with Becker disease often experience temporary attacks of muscle weakness, particularly in the arms and hands, brought on by movement after periods of rest. They may also develop mild, permanent muscle weakness over time. This muscle weakness is not seen in people with Thomsen disease.
A very rare syndrome characterized mainly by mental retardation, skeletal anomalies and delayed muscle relaxation
Myotonic Dystorphy 1 is a rare genetic disorder characterized by myotonia, muscle atrophy, cataracts and hypogonadism
Myotonic Dystorphy 2 is an inherited disorder characterized by progressive muscle weakness and wasting as well as eye defects, heart abnormalities and other anomalies. The severity of the condition is greatly variable. There are two type of myotonic dystrophy with type 1 being more severe than type 2. Type 2 also tends to affect muscle closer to the trunk e.g. upper leg and shoulders
Myotubular myopathy (also called Centronuclear myopathy) is a group of congenital myopathies where cell nuclei are abnormally located in skeletal muscle cells. In Myotubular myopathy the nuclei are located at a position in the center of the cell, instead of their normal location at the periphery.
Symptoms of Myotubular myopathy include severe hypotonia, hypoxia-requiring breathing assistance, and scaphocephaly. Among centronuclear myopathies, the X-linked myotubular myopathy form typically presents at birth, and is thus considered a congenital myopathy. However, some centronuclear myopathies may present later in life.
Myxedema (British English: myxoedema) is a skin and tissue disorder usually due to severe prolonged hypothyroidism. Hypothyroidism can be caused by atrophic disease, Hashimoto's thyroiditis, surgical removal of the thyroid, and rarer conditions. Partial forms of myxedema, especially of the lower legs (called pretibial myxedema), occasionally occur in adults with Graves' disease, a cause of hyperthyroidism; or also Hashimoto's thyroiditis without severe hypothyroidism.
A form of malignant tumor. It is a subtype of liposarcoma and is frequently located in the deeper layers of soft tissue of the arms and legs such as the thigh.
A very rare syndrome characterized by spotty pigmentation on the skin and the development of multiple benign tumors (myxoma) that can occur just about anywhere in the body but mainly in the skin, breast and heart and endocrine glands such as the thyroid and pituitary gland. The symptoms are highly variable depending on the location, size and number of tumors. Endocrine gland tumors can affect hormone production and hence result in a range of symptoms.
X-linked myxomatous valvular disease is characterized by mitral valve dystrophy frequently associated with degeneration of the aortic valves affecting males and, to a lower severity, females. The first localization of a gene for myxomatous valvular diseases is the first step for the subclassification of these diseases. Abbreviations and Acronyms AML = anterior mitral leaflet F.VIII = antihemophilic factor VIII LAA = left atrial area LVOTD = left ventricular outflow tract diameter MVD = myxomatous valve dystrophies PML = posterior mitral leaflet RJA = regurgitating jet area Valvular disease with myxomatous degeneration forms a complex group of disorders. Common histological features and a clinical continuum from isolated nonsyndromic valvular defects (e.g., idiopathic mitral valve prolapse) to multivalvular diseases and syndromic disorders (e.g., Marfan syndrome) make it difficult to subclassify these heterogeneous and complex pathologies. Defects in fibrillin (1) and collagen genes (2) have already been identified in syndromic valvular disease. In other valvular dystrophies with myxomatous degeneration, identification of genetic defects would appear to be an essential step in their subclassification
A group of parasites that infect fish
N-acetyl glucosamine 6-sulfate sulfatase is a lysosomal enzyme found in all cells. It is encoded by the GNS gene. It is involved in the catabolism of heparin, heparan sulphate, and keratan sulphate. Deficiency of this enzyme results in the accumulation of complex carbohydrates in the body's cells and tissues and in the cellular organelles, the lysosomes. These complex carbohydrates, also known as mucopolysaccharides or glycosaminoglycans (GAGs), serve as the building blocks for connective tissues in the body.
Deficiency of the N-acetyl glucosamine 6-sulfate sulfatase is called mucopolysaccharidosis type IIID (Sanfilippo D syndrome), and was first described at the American Pediatric Society Annual Meeting by pediatrician, Sylvester Sanfilippo, in 1963. The approximate incidence of Sanfilippo D syndrome is about 1:1,000,000.
N-acetyl-alpha-D-galactosaminidase: A very rare enzyme deficiency (N-acetyl-alpha-D-galactosaminidase) which can occur in three forms: type I (infantile-onset neuroaxonal dystrophy), type II or Kanzaki disease (adult-onset) and type III (mild or moderate form)
N-acetylglutamate synthase (NAGS) deficiency is type of urea cycle disorder leading to hyperammonaemia. It is an inherited disorder that causes ammonia to accumulate in the blood. The product of NAGS, N-acetylglutamate (NAG), is an allosteric activator of carbamylphosphate synthetase I (CPSI), the enzyme catalysing the first step in ureagenesis. In patients with NAGS deficiency, NAG is not available in sufficient quantities, or is not present at all and, hence, the body levels of ammonia increase.
Ammonia, which is formed when proteins and amino acids are broken down in the body, is toxic if the levels become too high. The nervous system is especially sensitive to the effects of excess ammonia. The disorder is very rare and the prevalence is unknown. Only a handful of cases have been described worldwide.
Nablus mask-like facial syndrome is a rare microdeletion syndrome, characterized by a mask-like facial appearance.
In 2000, Teebi, was the first to report on a 4 years old boy affected with NMFLS. Since then, a handful of additional patients have been reported.
Methemoglobinemia due to NADH-cytochrome b5 reductase deficiency (recessive congenital methemoglobinemia, RCM) is an autosomal recessive disorder characterized clinically by decreased oxygen carrying capacity of the blood, with resultant cyanosis and hypoxia.
There are 2 types of RCM. In type I, the defect affects the soluble form of the enzyme, is restricted to red blood cells, and causes well-tolerated methemoglobinemia. In type II, the defect affects both the soluble and microsomal forms of the enzyme and is thus generalized, affecting red cells, leukocytes, and all body tissues. Type II methemoglobinemia is associated with mental deficiency and other neurologic symptoms. The neurologic symptoms may be related to the major role played by the cytochrome b5 system in the desaturation of fatty acids.
Naegeli syndrome is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Naegeli syndrome, or a subtype of Naegeli syndrome, affects less than 200,000 people in the US population.
Naguib-Richieri-Costa syndrome (NRCS) is a very rare syndrome associating an acro-fronto-facio-nasal dysostosis with genitourinary anomalies. It has been described in three consanguineous families, with parents being first cousins.
The suggested inheritance pattern is autosomal recessive, with an incidence of less than 1 per million.
Nail-patella syndrome is an autosomal dominant condition characterized by the classical clinical tetrad of nail dysplasia, patellar aplasia-hypoplasia, elbow arthrodysplasia, and iliac horns. The nails may be absent, hypoplastic, or dystrophic with ridges, pits, and/or triangular lunulae.
Nail-patella syndrome has been recognized for more than 100 years. It has an estimated prevalence of 1 per 50,000 live births (US). Males and females are equally affected.
Nakajo-Nishimura syndrome (NNS) is an inherited condition that affects many parts of the body and has been described only in the Japanese population. Beginning in infancy or early childhood, affected individuals develop red, swollen lumps (nodular erythema) on the skin that occur most often in cold weather; recurrent fevers; and elongated fingers and toes with widened and rounded tips (clubbing).
Later in childhood, affected individuals develop joint pain and joint deformities called contractures that limit movement, particularly in the hands, wrists, and elbows. They also experience weakness and wasting of muscles, along with a loss of fatty tissue (lipodystrophy), mainly in the upper body. The combination of muscle and fat loss worsens over time, leading to an extremely thin (emaciated) appearance in the face, chest, and arms.
Other signs and symptoms of Nakajo-Nishimura syndrome can include an enlarged liver and spleen (hepatosplenomegaly), a shortage of red blood cells (anemia), a reduced amount of blood clotting cells called platelets (thrombocytopenia), and abnormal deposits of calcium (calcification) in an area of the brain called the basal ganglia. Intellectual disability has been reported in some affected individuals.
Nakajo-Nishimura syndrome appears to be rare and has been described only in the Japanese population. About 30 cases have been reported in the medical literature. Consanguinity or familial history is observed in about seventy percent of the affected families.
Hereditary spastic paraplegia (SPG or HSP) is characterized by progressive weakness and spasticity of the lower limbs due to degeneration of corticospinal axons. SPG11 is a form of complicated SPG, in that it has neurologic features in addition to spasticity.
The estimated prevalence for HSP of all types ranges from 1:100,000 to 10:100,000 depending on the country.
Nance-Horan syndrome is a rare genetic disorder that may be evident at birth (congenital). It is primarily characterized by abnormalities of the teeth and clouding of the lens of the eyes (congenital cataracts), resulting in poor vision. Additional eye (ocular) abnormalities are also often present, such as unusual smallness of the front, clear portion of the eye through which light passes (microcornea) and involuntary, rapid, rhythmic eye movements (nystagmus). In some cases, the disorder may also be associated with additional physical abnormalities and/or intellectual impairment. The range and severity of symptoms may vary greatly from one person to another, including among affected members of the same family.
Nance-Horan syndrome is inherited as an X-linked trait that it is usually fully expressed in males only. However, females who carry a single copy of the disease gene (heterozygotes) may manifest some of the symptoms and findings associated with the disorder. These may include microcornea and/or clouding of the lens of the eyes (posterior sutural cataract). Symptoms are less severe than those of affected males, potentially causing only slightly decreased clearness or clarity of vision (visual acuity). In some cases, abnormalities of the teeth may also be present. Intellectual impairment rarely occurs in females.
The disorder is present at birth (congenital). Fewer than 50 families (kindreds) have been described in the medical literature. The exact incidence of the disorder is unknown.
Narcolepsy is a chronic brain disorder that involves poor control of sleep-wake cycles. People with narcolepsy have episodes of extreme daytime sleepiness and sudden, irresistible bouts of sleep (called "sleep attacks") that can occur at any time, and may last from seconds or minutes. Other signs and symptoms may include cataplexy (a sudden loss of muscle tone that makes a person go limp or unable to move); vivid dream-like images or hallucinations; and/or total paralysis just before falling asleep or after waking-up. Narcolepsy may have several causes, the most common being low levels of the neurotransmitter hypocretin (for various possible reasons). The disorder is usually sporadic but some cases are familial. There is no cure, but some symptoms can be managed with medicines and lifestyle changes.
Neuropathy, ataxia, and retinitis pigmentosa (NARP) is a clinically heterogeneous progressive condition characterized by a combination of proximal neurogenic muscle weakness, sensory-motor neuropathy, ataxia, and pigmentary retinopathy.
The prevalence of NARP is unknown. This disorder is probably less common than a similar but more severe condition, Leigh syndrome, which affects about 1 in 40,000 people.
Nasal polyposis, familial ( also known as nose polyposis, familial) is a familial condition characterized by the development of nasal polyps.
Nasodigitoacoustic syndrome is a rare congenital syndrome first described by J.A. Keipert and colleagues in 1973. The syndrome is characterized by a misshaped nose, broad thumbs and halluces (the big toes), brachydactyly, sensorineural hearing loss, facial features such as hypertelorism (unusually wide-set eyes), and developmental delay.
The incidence of the syndrome has not been determined, but it is considered to affect less than 200,000 people in the United States, and no greater than 1 per 2,000 in Europe.