Diseases

Mucha-Habermann disease

Pityriasis lichenoides is a rare cutaneous disorder of unknown etiology. Pityriasis lichenoides encompasses a spectrum of clinical presentations ranging from acute papular lesions that rapidly evolve into pseudovesicles and central necrosis (pityriasis lichenoides et varioliformis acuta or PLEVA) to small, scaling, benign-appearing papules (pityriasis lichenoides chronica or PLC). Although historically, the term Mucha-Habermann disease has referred only to PLEVA, the term applies broadly to the entire spectrum of disease including PLC. A rare febrile ulceronecrotic variant has been reported, which is a severe form of PLEVA with high fever and marked constitutional symptoms. Lesions may self-involute and resolve completely over weeks, or new lesions occasionally may appear in crops, waxing and waning spontaneously for months to years thereafter

Muckle-Wells syndrome

Muckle–Wells syndrome (MWS, also known as UDA), is a rare autosomal dominant disease which causes sensorineural deafness, recurrent hives, and can lead to amyloidosis. Individuals with MWS often have episodic fever, chills, and joint pain. As a result, MWS is considered a type of periodic fever syndrome. MWS is caused by a defect in the CIAS1 gene which creates the protein cryopyrin. MWS is closely related to two other syndromes, familial cold urticaria and neonatal onset multisystem inflammatory disease—in fact, all three are related to mutations in the same gene and subsumed under the term cryopyrin-associated periodic syndromes (CAPS).

Mucolipidosis type 4

Mucolipidosis type IV is an inherited disorder characterized by delayed development and vision impairment that worsens over time.

People with typical mucolipidosis type IV have delayed development of mental and motor skills (psychomotor delay). Motor skills include sitting, standing, walking, grasping objects, and writing. Mutations in the MCOLN1 gene cause mucolipidosis type IV. This gene provides instructions for making a protein called mucolipin-1. This protein is located in the membranes of lysosomes and endosomes, compartments within the cell that digest and recycle materials. While its function is not completely understood, mucolipin-1 plays a role in the transport (trafficking) of fats (lipids) and proteins between lysosomes and endosomes.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations.

Mucolipidosis type I

Mucolipidosis type I, also known as sialidosis, is a rare inherited metabolic disorder characterized by a deficiency of the enzyme neuraminidase (sometimes referred to as sialidase). Deficiency of neuraminidase results in the abnormal accumulation of toxic materials in the body. Sialidosis is divided into two types (i.e., type I and type II). Sialidosis type I usually becomes apparent during the second decade of life with the development of sudden involuntary muscle contractions (myoclonus), distinctive red spots (cherry-red macules) in the eyes, and sometimes additional neurological findings. Sialidosis type II is usually more severe than sialidosis type I. Type II often begins during infancy or later during childhood and is characterized by cherry-red macules, mildly coarse facial features, skeletal malformations and mild cognitive impairment. Sialidosis is inherited as an autosomal recessive trait.

Mucolipidosis type II

Mucolipidosis type II alpha/beta, also referred to as Inclusion-cell (I-cell) disease, is part of the lysosomal storage disease family and results from deficiency of several lysosomal enzymes. The coding and translation of the genes for these enzymes is normal, however, they are not normally transported to the lysosomes from the endoplasmic reticulum because they lack a specific targeting signal. Without the proper functioning of N-acetylglucosamine-1-phototransferase, a build up of substances occur when enzymes are unable to travel inside of the lysosome.

Mucolipidosis II alpha/beta is a rare disorder, although its exact prevalence is unknown. It is estimated to occur in about 1 in 100,000 to 400,000 individuals worldwide. This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Mucolipidosis type III

Mucolipidosis (ML) III, also called as Pseudo-Hurler polydystrophy, a rare inherited biochemical disorder involving the progressive accumulation of certain chemicals (glycoproteins and glycolipids) in body tissues due to deficiency of an enzyme (UDP-N-acetylglucosamine-I-phosphotransferase) needed to process it. Mucolipidosis III is a slowly progressive disorder that affects many parts of the body. Signs and symptoms of this condition typically appear around age 3 or 4, but some children are not diagnosed until later on in life.

Mucopolysaccharidosis type I

Mucopolysaccharidosis I (MPS I) is a condition that affects many parts of the body. It is a progressively debilitating disorder; however, the rate of progression varies among affected individuals. MPS I is caused by mutations in the IDUA gene. These mutations lead to reduced levels or the complete lack of the IDUA enzyme. Without the proper amount of this enzyme, large sugar molecules called glycosaminoglycans (GAGs) accumulate within cells called lysosomes. This causes the lysosomes to increase in size, causing many different organs and tissues of the body to become enlarged. This leads to the medical problems seen in the condition.

MPS I was once divided into three separate syndromes: Hurler syndrome, Hurler-Scheie syndrome, and Scheie syndrome, listed from most to least severe. Because no biochemical differences have been identified and the clinical findings overlap, the condition is now divided into two subtypes,: severe MPS I and attenuated MPS I. People with severe MPS I typically have an earlier onset of symptoms, a decline in intellectual function, and a shorter lifespan. Although there is no cure for MPS I, bone marrow transplant and enzyme replacement therapy are treatment options that may help manage the symptoms of this condition.

Mucopolysaccharidosis type IV-B

Morquio syndrome is an inherited disease of metabolism in which the body is missing or doesn't have enough of a substance needed to break down long chains of sugar molecules called glycosaminoglycans (formerly called mucopolysaccharides). The syndrome belongs to a group of diseases called mucopolysaccharidoses (MPS). Specifically, it is known as MPS IV.

Mucopolysaccharidosis Type IVA

Mucopolysaccharidosis type IV, also known as Morquio syndrome, is a progressive condition that mainly affects the skeleton. The rate at which symptoms worsen varies among affected individuals.

The first signs and symptoms of MPS IV usually become apparent during early childhood. Affected individuals develop various skeletal abnormalities, including short stature, knock knees, and abnormalities of the ribs, chest, spine, hips, and wrists. People with MPS IV often have joints that are loose and very flexible (hypermobile), but they may also have restricted movement in certain joints. A characteristic feature of this condition is underdevelopment (hypoplasia) of a peg-like bone in the neck called the odontoid process. The odontoid process helps stabilize the spinal bones in the neck (cervical vertebrae). Odontoid hypoplasia can lead to misalignment of the cervical vertebrae, which may compress and damage the spinal cord, resulting in paralysis or death.

In people with MPS IV, the clear covering of the eye (cornea) typically becomes cloudy, which can cause vision loss. Some affected individuals have recurrent ear infections and hearing loss. The airway may become narrow in some people with MPS IV, leading to frequent upper respiratory infections and short pauses in breathing during sleep (sleep apnea). Other common features of this condition include mildly "coarse" facial features, thin tooth enamel, multiple cavities, heart valve abnormalities, a mildly enlarged liver (hepatomegaly), and a soft out-pouching around the belly-button (umbilical hernia) or lower abdomen (inguinal hernia). Unlike some other types of mucopolysaccharidosis, MPS IV does not affect intelligence.

The life expectancy of individuals with MPS IV depends on the severity of symptoms. Severely affected individuals may survive only until late childhood or adolescence. Those with milder forms of the disorder usually live into adulthood, although their life expectancy may be reduced. Spinal cord compression and airway obstruction are major causes of death in people with MPS IV.

Mucopolysaccharidosis type VI

Mucopolysaccharidosis type 6 (MPS 6), also known as Maroteaux-Lamy syndrome, is a progressive condition that causes many tissues and organs to enlarge and become inflamed or scarred. Skeletal abnormalities are also common in this condition. The rate at which symptoms worsen varies among affected individuals.

Mucormycosis

Mucormycosis is the broadest term to refer to infections caused by bread mold fungi of the zygomycota phylum. However, because zygomycota has been identified as polyphyletic, and is not included in modern fungal classification systems, the diseases that zygomycosis can refer to are better called by their specific names: mucormycosis (after Mucorales), phycomycosis (after Phycomycetes) and basidiobolomycosis (after Basidiobolus). These rare yet serious and potentially life-threatening fungal infections usually affect the face or oropharyngeal (nose and mouth) cavity. Zygomycosis type infections are most often caused by common fungi found in soil and decaying vegetation. While most individuals are exposed to the fungi on a regular basis, those with immune disorders (immunocompromised) are more prone to fungal infection. These types of infections are also common after natural disasters, such as tornadoes or earthquakes, where people have open wounds that have become filled with soil or vegetative matter.

The condition may affect the gastrointestinal tract or the skin. In non-trauma cases, it usually begins in the nose and paranasal sinuses and is one of the most rapidly spreading fungal infections in humans. Common symptoms include thrombosis and tissue necrosis. Treatment consists of prompt and intensive antifungal drug therapy and surgery to remove the infected tissue. The prognosis varies vastly depending upon an individual patient's circumstances.

Muenke Syndrome

A rare inherited condition characterized by the premature fusion of particular skull bones.

Mulibrey Nanism syndrome

A very rare inherited malformation characterized by very small stature (dwarfism), pericardial constriction and yellow dots in fundus of the eye.

Mullerian agenesis

Müllerian agenesis is a congenital malformation in women characterised by a failure of the Müllerian ducts to develop, resulting in a missing uterus and variable malformations of the vagina. It is the second most common cause of primary amenorrhea. The condition is also called MRKH or Mayer-Rokitansky-Küster-Hauser Syndrome, named after August Franz Joseph Karl Mayer, Carl Freiherr von Rokitansky, Hermann Küster, and G.A.Hauser.

Mullerian aplasia

A birth defect involving the absence of the uterus, cervix and top part of the vagina but normal external genitals and ovarian function. Secondary sexual characteristics generally develop normally but menstruation is absent.

Mullerian derivatives- persistent

A very rare syndrome where a genetic defect results in the development of female organs in an otherwise normal male. The genetic defect causes a hormone deficiency (anti-mullerian hormone) which allows mullerian derivates, such as a uterus, to form in males.

Multicentric Castleman’s Disease

Multicentric Castleman disease (MCD) is an uncommon lymphoproliferative disorder that share common lymph node histological features that occur systemically (multicentric).

MCD involves hyperactivation of the immune system, excessive release of proinflammatory chemicals (cytokines), proliferation of immune cells (B cells and T cells), and multiple organ system dysfunction. Castleman disease must be distinguished from other disorders that can demonstrate "Castleman-like" lymph node features, including reactive lymph node hyperplasia, autoimmune disorders, and malignancies. While not officially considered a cancer, the overgrowth of lymphocytes with this disease is similar to lymphoma and more research is needed to search for small populations of neoplastic cells. Castleman disease is a focus of intense ongoing research.

Multicentric reticulohistiocytosis

Multicentric reticulohistiocytosis (MRH) is a rare disease in which papulonodular skin lesions containing a proliferation of true histiocytes (macrophages) are associated with arthritis. The arthritis involves the interphalangeal joints and becomes severe enough to cause severe destruction of the joints (known as arthritis mutilans) in 45% of cases (see Media File 1). The disease can involve the bones, the tendons, the muscles, the joints, and nearly any other organ (eg, eyes, larynx, thyroid, salivary glands, bone marrow, heart, lung, kidney, liver, gastrointestinal tract). It has been associated with an underlying internal malignancy in about one fourth of cases, suggesting that MRH may be a paraneoplastic condition. The proliferating histiocytes in this disease are thought to be reactive and are not themselves malignant. Also see Multicentric Reticulohistiocytosis.

Multicore disease

A nonprogressive congenital muscle disease which mainly involves weakness of the proximal muscles. The severity of symptoms is variable.

Multicystic renal dysplasia- bilateral

A rare congenital disorder where multiple cysts develop in the kidneys which affects their ability to function normally. The condition is results in death prior to or within weeks of birth.

Multifocal fibrosclerosis

A rare disorder characterized by the development of fibrous tissue that can occur in various parts of the body such as the retroperitoneum, mediastinum, eye area, bile ducts and thyroid gland. The severity and range of involvement is variable. There is no obvious cause for the condition.

Multifocal heterotopia

A rare inherited disorder where a part of the brain tissue is misplaced during development. More specifically, brain tissue is abnormally located in multiple locations within the brain.

Multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare neuropathy characterized by progressive, asymmetric muscle weakness and atrophy (wasting). Signs and symptoms include weakness in the hands and lower arms; cramping; involuntary contractions or twitching; and atrophy of affected muscles. MMN is thought to be due to an abnormal immune response, but the underlying cause is not clear. Most people treated with intravenous immune globulin (IVIG) have rapid improvement in weakness, but maintenance IVIG is usually required for sustained improvement.
Clinically, it may resemble amyotrophic lateral sclerosis (ALS) with predominant lower motor neuron involvement, but muscle atrophy and more rapid progression are lacking. Duration of disease prior to diagnosis ranges from several months to more than 15 years. 

Multinodular goiter cystic kidney polydactyly

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