Amyotonia congenita is an indefinite term for a number of congenital neuromuscular disorders that cause generalized loss of muscle tone, and sometimes weakness, in infants and young children; most such disorders have a benign course.
Amyotrophic lateral sclerosis (ALS), is a progressive motor neuron disease which leads to problems with muscle control and movement. There are various types of ALS, which are distinguished by their signs and symptoms and their cause. Early symptoms may include muscle twitching, cramping, stiffness, or weakness, eventually followed by slurred speech and difficulty chewing or swallowing (dysphagia). As the disease progresses, individuals become weaker are are eventually wheelchair-dependent. Death often results from respiratory failure within 2 to 10 years after the onset of symptoms. Most affected individuals have a sporadic (not inherited) form of ALS; about 5-10% have a familial (inherited) form of the condition. Familial ALS may caused by mutations in any one of several genes and the pattern of inheritance varies depending on the gene involved. Treatment is generally supportive.
Amyotrophic lateral sclerosis type 2 is an inherited form of Amyotrophic lateral sclerosis (ALS), which develops in a person's teens or twenties. ALS is characterized by progressive degeneration of motor neurons which results in muscle weakness and atrophy. An important gene associated with Amyotrophic Lateral Sclerosis Type 2 is ALS2 (amyotrophic lateral sclerosis 2 (juvenile)).
Amyotrophic lateral sclerosis type 6 is an inherited disorder involving progressive degeneration of motor neurons which results in muscle weakness and atrophy. Type 6 is caused by a defect on chromosome 16 in FUS gene. Type 6 is characterized adult onset of symptoms with progression varying between 1 and 20 years. It occurs in an autosomal dominant pattern of inheritance.
Amyotrophic lateral sclerosis-parkinsonism-dementia complex is a nerve degeneration disorder that involves progressive dementia and parkinsonism which ultimately leads to death.
Monomelic amyotrophy (MMA) is an untreatable, focal motor neuron disease that primarily affects young (15- to 25-year-old) males especially in India and Japan. MMA is marked by insidious onset of muscular atrophy, which stabilizes at a plateau after two to five years from which it neither improves nor worsens. There is no pain or sensory loss associated with MMA. Unlike other lower motor neuron diseases, MMA is not believed to be hereditary and fasciculations (involuntary muscle twitches) are rare.
EMG tests reveal loss of the nerve supply, or denervation, in the affected limb without conduction block (nerve blockage restricted to a small segment of the nerve). Increased sweating, coldness and cyanosis have been reported for a few patients, indicating involvement of the sympathetic nervous system.
While MMA will cause weakness and/or wasting in only one limb, EMG and NCV tests often show signs of reinnervation in the unaffected limbs.
An inherited disorder involving muscle wasting and weakness in the shoulder and lower leg. The exact symptoms that occur may vary from patient to patient with males often being more affected than females. An interesting observation of this condition is that symptoms and rate of progression tends to be more severe with each passing generation.
Anal cancer is a cancer (malignant tumor) which arises from the anus, the distal opening of the gastrointestinal tract through which stool leaves your body. It is a distinct entity from the more common colorectal cancer.
Anal cancer is typically an anal squamous cell carcinoma that arises near the squamocolumnar junction, often linked to human papillomavirus (HPV) infection. It may be keratinizing (basaloid) or non-keratinizing (cloacogenic). Other types of anal cancer are adenocarcinoma, lymphoma,sarcoma or melanoma.
Anal sphincter dysplasia (ASDP) is a malformation of the anal canal. Anal dysplasia is a pre-cancerous condition which occurs when the lining of the anal canal undergoes abnormal changes. It can be classified as low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL). Most cases are not associated with symptoms, but people may notice lumps in and around the anus.
Anaplastic large cell lymphoma is a rare type of non-Hodgkin lymphoma. It is made up of either malignant T-cells (type of cells in the immune system), or 'Null-lymphocytes' (lack both B or T-cell markers).
It is described in detail in the "Classification of Tumors of the Hematopoietic and Lymphoid Tissues" edited by experts of the World Health Organisation. The term anaplastic large cell lymphoma encompasses at least 4 different clinical entities, all sharing the same name, and histologically have also in common the presence of large pleomorphic cells that express CD30 and T-cell markers. Two types of ALCL present as systemic disease and are considered as aggressive lymphomas, while two types present as localized disease and may progress locally. Its name derives from anaplasia and large-cell lymphoma.
It is accounting for about one in 50 of all cases. It can occur at any time between childhood and old age, but is most common in children and young adults. It is about twice as common in men as in women.
A group of patients with non-small cell lung cancer (NSCLC) have tumors that contain an inversion in chromosome 2 that juxtaposes the 5' end of the echinoderm microtubule-associated protein-like 4 (EML4) gene with the 3' end of the anaplastic lymphoma kinase (ALK) gene, resulting in the novel fusion oncogene EML4-ALK. This fusion oncogene rearrangement is transforming both in vitro and in vivo and defines a distinct clinicopathologic subset of NSCLC.
A rare type of cancer where a tumor develops in lymph tissue and consists mainly of small cells. It is a form of non-Hodgkin's lymphoma. The tumors can develop in more than one lymph node and can also occur in the skin and various organs such as the liver, bones or lungs.
A rare disorder characterized by abnormal skeletal and spinal development.
Ancylostoma duodenale is one of two parasitic hookworms which can cause serious infections in human intestines - Hookworms feed on the blood of the host. Severe infections can cause chronic blood loss and related anemia.
Human infection with A duodenale is estimated to affect approximately one fourth of the world's population. Infection is most prevalent in tropical and subtropical zones, roughly between the latitudes of 45°N and 30°S. Hookworm infection occurs only in isolated temperate areas.
Infection is endemic in most developing countries. However, even in endemic regions, infection is usually confined to rural areas, especially where human feces are used as fertilizer or where sanitation is inadequate. In developed countries, infection is most commonly encountered in travelers, immigrants, and adoptees from developing countries.
A duodenale is the predominant species in the Mediterranean region, in northern regions of India and China, and in North Africa.
A light infection causes abdominal pain, loss of appetite and geophagy. Heavy infection causes severe protein deficiency or iron deficiency anemia. Protein deficiency may lead to dry skin, edema and potbelly, while iron deficiency anemia might result in mental dullness and heart failure.
Anderson-Tawil syndrome is a disorder that causes episodes of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and developmental abnormalities. The most common changes affecting the heart are ventricular arrhythmia, which is a disruption in the rhythm of the heart’s lower chambers, and long QT syndrome. Long QT syndrome is a heart condition that causes the heart (cardiac) muscle to take longer than usual to recharge between beats. If untreated, the irregular heartbeats can lead to discomfort, fainting (syncope), or cardiac arrest.
Physical abnormalities associated with Andersen-Tawil syndrome typically affect the head, face, and limbs. These features often include a very small lower jaw (micrognathia), dental abnormalities, low-set ears, widely spaced eyes, and unusual curving of the fingers or toes (clinodactyly). Some affected people also have short stature and an abnormal curvature of the spine (scoliosis).
Two types of Andersen-Tawil syndrome are distinguished by their genetic causes. Type 1, which accounts for about 60 percent of all cases of the disorder, is caused by mutations in the KCNJ2 gene. The remaining 40 percent of cases are designated as type 2; the cause of these cases is unknown.
Androgen insensitivity syndrome (AIS) is a condition that affects sexual development before birth and during puberty. People with this condition are genetically male, with one X chromosome and one Y chromosome in each cell. Because their bodies are unable to respond to certain male sex hormones (called androgens), they may have mostly female sex characteristics or signs of both male and female sexual development.
Complete androgen insensitivity syndrome occurs when the body cannot use androgens at all. People with this form of the condition have the external sex characteristics of females, but do not have a uterus and therefore do not menstruate and are unable to conceive a child (infertile). They are typically raised as females and have a female gender identity. Affected individuals have male internal sex organs (testes) that are undescended, which means they are abnormally located in the pelvis or abdomen. Undescended testes can become cancerous later in life if they are not surgically removed. People with complete androgen insensitivity syndrome also have sparse or absent hair in the pubic area and under the arms.
The partial and mild forms of androgen insensitivity syndrome result when the body's tissues are partially sensitive to the effects of androgens. People with partial androgen insensitivity (also called Reifenstein syndrome) can have normal female sex characteristics, both male and female sex characteristics, or normal male sex characteristics. They may be raised as males or as females, and may have a male or a female gender identity. People with mild androgen insensitivity are born with male sex characteristics, but are often infertile and tend to experience breast enlargement at puberty.
Androgenetic alopecia is a common form of hair loss in both men and women. In men, this condition is also known as male-pattern baldness. Hair is lost in a well-defined pattern, beginning above both temples. Over time, the hairline recedes to form a characteristic "M" shape. Hair also thins at the crown (near the top of the head), often progressing to partial or complete baldness.
The pattern of hair loss in women differs from male-pattern baldness. In women, the hair becomes thinner all over the head, and the hairline does not recede. Androgenetic alopecia in women rarely leads to total baldness.
Androgenetic alopecia in men has been associated with several other medical conditions including coronary heart disease and enlargement of the prostate. Additionally, prostate cancer, disorders of insulin resistance (such as diabetes and obesity), and high blood pressure (hypertension) have been related to androgenetic alopecia. In women, this form of hair loss is associated with an increased risk of polycystic ovary syndrome (PCOS). PCOS is characterized by a hormonal imbalance that can lead to irregular menstruation, acne, excess hair elsewhere on the body (hirsutism), and weight gain.
A rare inherited condition characterized by anemia at birth as well as spinocerebellar ataxia (impaired ability to control voluntary movements).
Hereditary spherocytic hemolytic anemia is a rare blood disorder characterized by defects within red blood cells (intracorpuscular) that result in a shortened survival time for these cells. Red blood cells (erythrocytes) normally circulate for a few months and when they die off are replaced by new erythrocytes. However, in hereditary spherocytic hemolytic anemia, the cells die prematurely. They also have low amounts of fats (lipid) in the cell membranes and an abnormally small amount of surface area. The red blood cells are sphere-shaped (spherocytic) making it difficult for them to pass through the spleen, resulting in the early destruction of these cells (hemolysis). The sphere shape of the red blood cells is the hallmark of this disorder, and this abnormality may be identified under a microscope. Hereditary spherocytic hemolytic anemia is caused by an inherited metabolic defect.
Diamond-Blackfan anemia is an inherited blood disorder that affects the ability of the bone marrow to produce red blood cells. It is usually diagnosed during the first year of life. Individuals with Diamond-Blackfan anemia may also have physical abnormalities of the face head, upper limbs, hands (mostly involving the thumbs), genitalia, urinary tract, and heart. Some affected individuals also have short stature.
This disease a macrocytic anemia resulting from congenital hypoplasia of the bone marrow, which is grossly deficient in erythroid precursors whereas other elements are normal; anemia is progressive and severe, but leukocyte and platelet counts are normal or slightly reduced; survival of transfused erythrocytes is normal; minor congenital anomalies are found in some patients. Both autosomal dominant and recessive forms have been described, caused by mutation in the gene encoding ribosomal protein S19 (RBS19) on chromosomal 19q. SYN: congenital nonregenerative anemia, Diamond-Blackfan anemia, Diamond-Blackfan syndrome, erythrogenesis imperfecta, familial hypoplastic anemia, pure red cell anemia.
Sideroblastic anemia is caused by abnormal production of red blood cells (erythrocytes), usually as part of myelodysplastic syndrome, which can evolve into hematological malignancies (especially acute myelogenous leukemia). The body has iron available, but cannot incorporate it into hemoglobin. Abnormal red blood cells called sideroblasts are found in the blood of people with these anemias. Sideroblasts are seen, which are nucleated erythrocytes with granules of iron in their cytoplasm. Sideroblastic anemias are classified as hereditary, acquired, and reversible.
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Anencephaly is the absence of a major portion of the brain, skull, and scalp that occurs during embryonic development. It is a cephalic disorder that results from a neural tube defect that occurs when the rostral (head) end of the neural tube fails to close, usually between the 23rd and 26th day following conception. Strictly speaking, the Greek term translates as "no in-head" (that is, totally lacking the inside part of the head, i.e., the brain), but it is accepted that children born with this disorder usually only lack a telencephalon, the largest part of the brain consisting mainly of the cerebral hemispheres, including the neocortex, which is responsible for cognition. The remaining structure is usually covered only by a thin layer of membrane— skin, bone, meninges, etc. are all lacking. With very few exceptions, infants with this disorder do not survive longer than a few hours or possibly days after their birth.
Anencephaly and spina bifida X-linked is a severe X-linked malformation syndrome involving anencephaly where a part or all of the brain and associated skull is missing as well as a defect or opening in the spinal column
Aneuploidy is defined as an abnormal number of chromosomes. Syndromes caused by an extra or missing chromosome are among the most widely recognized genetic disorders in humans. Different organisms have widely varying chromosome complements and thus the term "aneuploidy" does not refer to a particular number of chromosomes, but rather the situation in which the chromosome content within a given cell is abnormal.
Chromosome abnormalities are detected in 1 of 160 live human births. Apart from sex chromosome disorders, most cases of aneuploidy result in death of the developing fetus (miscarriage); the most common extra autosomal chromosomes among live births are 21, 18 and 13.
Aneurysm of the aortic sinus is comparatively rare, occurring in about one person in every thousand. When present, it is usually in either the right (65-85%) or in the noncoronary (10-30%) sinus, rarely in the left (< 5%) sinus.
Aneurysm, intracranial berry-2 (ANIB2) is a bulge in a blood vessel in the brain. The bulge can rupture causing a stroke. They usually form as a result of high blood pressure and weak blood vessel walls in the brain. There are five different subtypes of intracranial berry aneurysms with each one caused by a defect in different gene. The defective gene increases and individuals risk for developing intracranial berry aneurysms. Type 2 is caused by a defect on chromosome 19q13.
An aneurysmal bone cyst is a blood-filled fibrous tumor-like cyst that expands the bone, giving it a "blow-out" appearance. It typically occurs in the second decade of life and can emerge in virtually any bone in the arms, legs, trunk or skull. The vertebrae and knee are the most common sites of occurrence. An aneurysmal bone cyst is a benign bone tumor, meaning that it does not metastasize (spread) to other regions of the body. It can however be quite destructive locally and has a high propensity for recurrence.
When it occurs in bones of a limb, it typically involves any of the following areas of the bone:
When it occurs in the spine, the cyst can grow to involve the entire vertebral body where it arose or it can involve the adjacent vertebrae. Generally, those cysts considered "active" could deform the host bone but remain contained in the bone, while others, considered "aggressive" extend beyond the bone to the adjacent soft connective tissues. Rarely will these types of cysts resolve on their own without treatment.
Angel shaped phalangoepiphyseal dysplasia (ASPED) is a rare genetic bone development disorder characterized mainly by an unusual angel-shaped ends of some bones (fingers and hips) which leads to early osteoarthritis.