Agenesis of corpus callosum (ACC) is a rare disorder that is present at birth (congenital). It is characterized by a partial or complete absence (agenesis) of an area of the brain that connects the two cerebral hemispheres. This part of the brain ...

Agenesis of corpus callosum (ACC) is a rare birth defect in which the corpus callosum, the band of nerve fibers connecting the two hemispheres of the brain, is either partially or completely absent. This condition can cause a variety of physical a...

Agenesis of the superior vena cava (SVC) is a rare congenital disorder in which the superior vena cava, a major vein that carries blood from the head and arms to the heart, is absent or incompletely formed. This condition can cause a variety of sy...

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Aggressive NK-cell leukemia is a rare type of cancer that affects a type of white blood cell called natural killer (NK) cells. It is an aggressive form of leukemia that is characterized by an overproduction of NK cells in the blood and bone marrow...

Aggressive systemic mastocytosis (ASM) is a rare, life-threatening disorder caused by an abnormal increase in mast cells in the body. Mast cells are a type of white blood cell that play an important role in the body’s immune system. In ASM, the ...

Agoraphobia is a fear of being outside or otherwise being in a situation from which one either cannot escape or from which escaping would be difficult or humiliating. Like other phobias, agoraphobia often goes unreported, probably b...

Acquired agranulocytosis is a rare, drug-induced blood disorder that is characterized by a severe reduction in the number of white blood cells (granulocytes) in the circulating blood. The name granulocyte refers to grain-like bodies within the cel...

A blood disorder characterized by low levels of white blood cells (granular leukocytes) in the circulating blood. The condition is usually caused by certain drugs especially chemotherapy drugs....

Agranulocytosis, acquired is a rare, life-threatening condition in which the body does not produce enough white blood cells, which are essential for fighting infection. It is caused by certain medications, infections, or autoimmune diseases. Sympt...

Classical lissencephaly, also known as lissencephaly type I, is a brain malformation that may occur as an isolated abnormality (isolated lissencephaly sequence [ILS]) or in association with certain underlying syndromes (e.g., Miller-Dieker syndrom...

AH amyloidosis is a rare type of amyloidosis caused by the buildup of abnormal proteins called amyloid light chains (AL) in the body's organs and tissues. It is a type of systemic amyloidosis, meaning it affects multiple organs and tissues. AH amy...

AHDC1-related intellectual disability-obstructive sleep apnea-mild dysmorphism syndrome is a rare genetic disorder caused by a mutation in the AHDC1 gene. It is characterized by intellectual disability, obstructive sleep apnea, and mild dysmorphis...

Ahumada-Del Castillo Syndrome is a rare genetic disorder characterized by intellectual disability, facial dysmorphism, and skeletal abnormalities. It is caused by a mutation in the gene encoding the transcription factor FOXG1. Symptoms of the diso...

Ahumada-Del Castillo is a rare endocrine disorder affecting adult females, which is characterized by impairment in the function of the pituitary and hypothalamus glands. Symptoms may include the production of breast milk (lactation) not associated...

AICA-ribosiduria is an inherited disorder caused by a deficiency of the enzyme AICA-ribosidase. This enzyme is responsible for breaking down the amino acid AICA-ribose, which is found in the body. People with this disorder have an accumulation of ...

Aicardi Syndrome is a rare genetic disorder that affects the development of the brain and the eyes. It is characterized by the absence of a structure in the brain called the corpus callosum, which is responsible for connecting the two hemispheres ...