Antisynthetase Syndrome (AS) is a rare autoimmune disorder that affects the muscles and lungs. It is caused by an immune system that produces antibodies against certain aminoacyl-tRNA synthetases, which are enzymes that help the body make proteins...

Antithrombin deficiency is a rare inherited disorder that affects the body's ability to control blood clotting. People with this disorder have low levels of antithrombin, a protein that helps to prevent the formation of blood clots. Without enough...

Antley-Bixler Syndrome is a rare genetic disorder that is primarily characterized by distinctive malformations of the head and facial (craniofacial) area and additional skeletal abnormalities. For example, the disorder is typically associated with...

Antley-Bixler Syndrome (ABS) is a rare genetic disorder that affects the development of the bones, joints, and other organs. It is characterized by skeletal malformations, including craniosynostosis (premature fusion of the skull bones), midface h...

Antley-Bixler syndrome with genital anomaly and disorder of steroidogenesis (ABS-GAD) is a rare genetic disorder characterized by skeletal malformations, genital anomalies, and a disorder of steroidogenesis. Skeletal malformations can include cran...

Antley-Bixler syndrome without genital anomaly or disorder of steroidogenesis is a rare genetic disorder characterized by skeletal abnormalities, facial malformations, and respiratory and digestive problems. It is caused by mutations in the FGFR2 ...

Aortic arch anomaly-facial dysmorphism-intellectual disability syndrome is a rare genetic disorder characterized by a combination of aortic arch anomalies, facial dysmorphism, and intellectual disability. It is caused by a mutation in the gene enc...

Aortic arch interruption is a rare congenital heart defect in which the aortic arch, the main artery that carries oxygen-rich blood from the heart to the rest of the body, is interrupted or blocked. This can lead to a decrease in blood flow to the...

Introduction to aortic dissection The aorta is the large blood vessel that leads from the heart and carries blood to the rest of the body. It originates at the aortic valve at the outlet of the left ventricle of the heart and ascends withi...

What is aortic stenosis? Aortic stenosis is abnormal narrowing of the aortic valve. A number of conditions cause disease resulting in narrowing of the aortic valve. When the degree of narrowing becomes significant enough to impede the flow...

Aortic stenosis is abnormal narrowing of the aortic valve. A number of conditions cause disease resulting in narrowing of the aortic valve. When the degree of narrowing becomes significant enough to impede the flow of blood from the left ventricle...

Aorto-left ventricular tunnel (ALVT) is a rare congenital heart defect in which a tunnel-like connection is formed between the aorta and the left ventricle of the heart. This connection allows oxygen-rich blood to flow from the aorta into the left...

Aorto-right ventricular tunnel (ARVT) is a rare congenital heart defect in which a tunnel-like connection is formed between the aorta and the right ventricle of the heart. This connection allows oxygen-rich blood from the aorta to mix with oxygen-...

Aorto-ventricular tunnel is a rare congenital heart defect in which a tunnel-like connection is formed between the aorta and the right ventricle of the heart. This connection allows oxygen-rich blood from the aorta to mix with oxygen-poor blood fr...

AP-4-Associated Hereditary Spastic Paraplegia (AP-4-HSP) is a rare, inherited neurological disorder that affects the nerves in the lower body. It is characterized by progressive spasticity and weakness of the legs, leading to difficulty walking. I...

Attenuated familial adenomatous polyposis (AFAP) is a rare form of familial adenomatous polyposis (FAP) that is caused by a mutation in the APC gene. AFAP is characterized by the presence of fewer than 100 adenomatous polyps in the colon, which is...

APECED syndrome or Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome is a genetic disorder. People...