An aneurysm is an abnormal area of localized widening of a blood vessel. The aorta bulges at the site of an aneurysm like a weak spot on a worn tire. Aortic aneurysms are typically spindle-shaped and involve the aorta belo...

An aneurysm of the sinus of Valsalva is a bulge or ballooning of the wall of one of the three sinuses of Valsalva, which are located in the heart. It is a rare condition that can cause serious complications, including aortic regurgitation, aortic ...

Aneurysm-osteoarthritis syndrome is a rare genetic disorder characterized by aneurysms (weakened and bulging blood vessels) in the brain and/or spinal cord, as well as osteoarthritis (degenerative joint disease). It is caused by a mutation in the ...

An aneurysmal bone cyst (ABC) is a rare, benign, expansile lesion of the bone that is characterized by a cystic cavity filled with blood. It is most commonly found in the long bones of the body, such as the femur, tibia, and humerus, but can also ...

Angel-shaped phalango-epiphyseal dysplasia (APED) is a rare genetic disorder that affects the growth of bones in the hands and feet. It is characterized by short stature, short fingers and toes, and a distinctive angel-shaped appearance of the epi...

Angelman Syndrome is a rare genetic disorder that affects the nervous system. It is characterized by severe developmental delays, intellectual disability, speech impairment, and movement and balance disorders. People with Angelman Syndrome often h...

Angelman syndrome is caused by a point mutation in the UBE3A gene, which is located on chromosome 15. This mutation results in the loss of function of the gene, which is responsible for the production of a protein called ubiquitin-protein ligase E...

Angelman syndrome is a genetic disorder caused by a defect in the imprinting process of the 15q11-q13 region of the genome. This region contains several genes that are important for normal brain development. When the imprinting process is disrupte...

Angelman syndrome is a genetic disorder caused by a deletion of a small piece of chromosome 15 in the region known as 15q11-q13. This deletion is usually inherited from the mother. The deletion results in the loss of several genes, which can lead ...

Angelman syndrome is a genetic disorder caused by a deletion of a small piece of chromosome 15, or by a mutation in the UBE3A gene located on the same chromosome. It is also caused by paternal uniparental disomy of chromosome 15, which is when bot...

What is angina? The heart is the pump responsible for circulating blood throughout the body. Myocardium (myo=muscle + cardium=muscle) is the heart muscle that contracts to pump that blood and like any other muscle, it requires oxygen rich ...

The heart is the pump responsible for circulating blood throughout the body. Myocardium (myo=muscle + cardium=muscle) is the heart muscle that contracts to pump that blood and like any other muscle, it requires oxygen rich blood for energy. Angina...

Angiocentric glioma is a rare type of brain tumor that is typically found in children and young adults. It is a low-grade tumor that is slow-growing and usually benign. It is characterized by the presence of abnormal blood vessels that are surroun...

Angioimmunoblastic T-Cell Lymphoma (AITL) is a rare type of non-Hodgkin lymphoma (NHL) that affects the T-cells of the immune system. It is characterized by the presence of abnormal T-cells in the blood and lymph nodes, as well as an increase in t...

Angiomatoid fibrous histiocytoma (AFH) is a rare type of soft tissue tumor that usually occurs in children and young adults. It is a benign tumor that is usually found in the arms, legs, or trunk. AFH is composed of a mixture of spindle cells, his...

Angioosteohypotrophic syndrome is a rare genetic disorder characterized by abnormal development of the blood vessels, bones, and muscles. It is caused by mutations in the PEX1 gene, which is responsible for the production of an enzyme called perox...

Angiosarcoma is a rare type of cancer that develops in the cells that line the blood vessels and lymph vessels. It is most commonly found in the skin, scalp, and soft tissues of the head and neck, but can also occur in other parts of the body. Sym...