Diseases

Mental retardation- X-linked- nonspecific

Non-specific X-linked mental retardation (MRX) is a very common disorder which affects approximately 1 in 600 males. Despite this high frequency, little is known about the molecular defects underlying this disorder, mainly because of the clinical and genetic heterogeneity which is evident from linkage studies. Recently, a collaborative study using the candidate gene approach demonstrated the presence of mutations in GDIalpha, a Rab GDP-dissociation inhibitor encoded by a gene localized in Xq28, associated with non-specific mental retardation.

Meralgia paresthetica

Meralgia paresthetica is a condition characterized by tingling, numbness and burning pain in the outer part of your thigh. The cause of meralgia paresthetica is compression of the nerve that supplies sensation to the skin surface of your thigh.

Meralgia paresthetica

Meralgia paresthetica is a condition characterized by tingling, numbness and burning pain in the outer part of your thigh. The cause of meralgia paresthetica is compression of a nerve — the lateral femoral cutaneous nerve — that supplies sensation to the skin surface of your upper leg. Common causes of this nerve compression include tight clothing, obesity or weight gain, and pregnancy. Meralgia paresthetica can also be due to nerve injury, from a disease such as diabetes or from trauma. Treatment for meralgia paresthetica is directed at relieving the compression and usually consists of self-care measures, such as wearing looser clothing or losing weight. In severe cases of meralgia paresthetica, treatment may include medications to treat the discomfort or, rarely, surgery.

Meretoja syndrome

Meretoja syndrome: A form of familial amyloid polyneuropathy characterized by deposits of a substance called amyloid in the skin on the face as well as the facial nerves which can cause symptoms such as weak facial muscles

Merkel cell cancer

Merkel cell carcinoma is a rare type of skin cancer that usually appears as a single, painless, lump on sun-exposed skin and it is typically red or violet in color. It usually appears as a flesh-colored or bluish-red nodule, often on your face, head or neck. It is considered fast-growing and can spread quickly to surrounding tissues, nearby lymph nodes, or more distant parts of the body. Merkel cell polyomavirus has been detected in about 80% of the tumors tested. It is thought that this virus can cause somatic mutations leading to MCC when the immune system is weakened. Other risk factors for developing MCC include ultraviolet radiation and being over 50 years of age. Treatment should begin early and depends on the location and size of the cancer, and the extent to which it has spread.

Merlob Grunebaum Reisner syndrome

A rare birth malformation where the thumb has three bones instead of the normal two which gives it a fingerlike appearance. An extra toe is also present.

Mesangial proliferative glomerulonephritis

Mesangial proliferative glomerulonephritis: A rare kidney disorder characterized by blood in the urine caused by a particular type of inflammation inside the kidneys. Immune system abnormalities result in abnormal immune deposits in the mesangial cells (part of the capillaries inside the kidneys) of the kidneys. The mesangial cells become bigger and their numbers increase as a result.

Mesangial sclerosis- diffuse

Mesangial sclerosis, diffuse: A rare inherited disorder involving a kidney disorder that starts early in life and rapidly progresses to kidney failure. Death often occurs within years of birth.

Mesenchymal tumor

A tumor that arises from soft tissue. Symptoms are determined by the size and location of the tumor. It is a usually aggressive tumor that can occur muscle, fat, bone and blood vessels.

Mesenteric artery ischemia

Mesenteric artery ischemia is a narrowing or blockage of one or more of the three mesenteric arteries, which are the major arteries supplying the small and large intestines.

Mesodermal defects lower type

Mesodermal defects lower type: A very rare syndrome characterized mainly by defects of the lower trunk area such as the pelvic organs.

Mesomelia

Mesomelia: Abnormally short forearms and lower legs.

Mesomelic syndrome Pfeiffer type

Reinhardt Pfeiffer syndrome (medical condition): A rare disorder characterized by short stature with underdeveloped ulna and fibula bone

Mesothelioma

Mesothelioma is a cancer that starts as a growth of cells in the mesothelium. The mesothelium is a thin layer of tissue that covers many internal organs.

Mesothelioma is pronounced me-zoe-thee-lee-O-muh. It most often happens in the tissue around the lungs. This is called pleural mesothelioma. Mesothelioma also can happen in the tissues in the belly, around the heart and around the testicles.

Mesothelioma, which is sometimes called malignant mesothelioma, is a fast-growing and deadly form of cancer. There are mesothelioma treatments. But for many people with mesothelioma, there is no cure.

Metabolic disorder

Metabolism is the process your body uses to get or make energy from the food you eat. Food is made up of proteins, carbohydrates and fats. Chemicals in your digestive system break the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body tissues, such as your liver, muscles and body fat. A metabolic disorder occurs when abnormal chemical reactions in your body disrupt this process. When this happens, you might have too much of some substances or too little of other ones that you need to stay healthy.

Metabolic Dysfunction-Associated Steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH), previously known as nonalcoholic steatohepatitis (NASH), is liver inflammation caused by a buildup of fat in the liver. MASH is part of a group of liver diseases, known as nonalcoholic fatty liver disease, in which fat builds up in the liver and sometimes causes liver damage that gets worse over time (progressive liver damage). Although the cause is not known, MASH seems to be related to certain other conditions, including obesity, high cholesterol and triglycerides, and diabetes. Treatment for MASH involves controlling those underlying diseases

Metachondromatosis

Metachondromatosis: A rare genetic disorder characterized by the development of firm lumps in the hands and feet caused by bony outgrowhts.

Metachromatic leukodystrophy

Metachromatic leukodystrophy is an inherited disorder characterized by the accumulation of fats called sulfatides in cells. This accumulation especially affects cells in the nervous system that produce myelin, the substance that insulates and protects nerves. Nerve cells covered by myelin make up a tissue called white matter. Sulfatide accumulation in myelin-producing cells causes progressive destruction of white matter (leukodystrophy) throughout the nervous system, including in the brain and spinal cord (the central nervous system) and the nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system).

The types, which may overlap, include:

  • Infantile form, occurring between ages 6 months and 2 years
  • Juvenile form, occurring between ages 3 and 6 (early juvenile) or between ages 6 and 16 (late juvenile)
  • Adult form, occurring at age 17 or older

In people with metachromatic leukodystrophy, white matter damage causes progressive deterioration of intellectual functions and motor skills, such as the ability to walk. Affected individuals also develop loss of sensation in the extremities (peripheral neuropathy), incontinence, seizures, paralysis, an inability to speak, blindness, and hearing loss. Eventually they lose awareness of their surroundings and become unresponsive. While neurological problems are the primary feature of metachromatic leukodystrophy, effects of sulfatide accumulation on other organs and tissues have been reported, most often involving the gallbladder.

The most common form of metachromatic leukodystrophy, affecting about 50 to 60 percent of all individuals with this disorder, is called the late infantile form. This form of the disorder usually appears in the second year of life. Affected children lose any speech they have developed, become weak, and develop problems with walking (gait disturbance). As the disorder worsens, muscle tone generally first decreases, and then increases to the point of rigidity. Individuals with the late infantile form of metachromatic leukodystrophy typically do not survive past childhood.

In 20 to 30 percent of individuals with metachromatic leukodystrophy, onset occurs between the age of 4 and adolescence. In this juvenile form, the first signs of the disorder may be behavioral problems and increasing difficulty with schoolwork. Progression of the disorder is slower than in the late infantile form, and affected individuals may survive for about 20 years after diagnosis.

The adult form of metachromatic leukodystrophy affects approximately 15 to 20 percent of individuals with the disorder. In this form, the first symptoms appear during the teenage years or later. Often behavioral problems such as alcoholism, drug abuse, or difficulties at school or work are the first symptoms to appear. The affected individual may experience psychiatric symptoms such as delusions or hallucinations. People with the adult form of metachromatic leukodystrophy may survive for 20 to 30 years after diagnosis. During this time there may be some periods of relative stability and other periods of more rapid decline.

Metachromatic leukodystrophy gets its name from the way cells with an accumulation of sulfatides appear when viewed under a microscope. The sulfatides form granules that are described as metachromatic, which means they pick up color differently than surrounding cellular material when stained for examination.

Metagonimiasis

Metagonimiasis: Infection with a parasitic intestinal fluke called Metagonimus yokogawa. Infection usually occurs when eating undercooked or salted fish which are infected with the parasite. It is most common in the Far East, Siberia, Israel and Spain

Metaphyseal acroscyphodysplasia

Metaphyseal acroscyphodysplasia: A very rare syndrome characterized mainly by bone abnormalities mainly involving the legs, and fingers and the arms to a lesser extent.

Metaphyseal anadysplasia

Metaphyseal anadysplasia (medical condition): A very rare syndrome where abnormal bone development starts early in life and is fairly severe but after a few years, the bones return to almost normal. Adult height is nearly normal and bowed limbs usually straighte