Dictionary

acrochordon See skin tag.

acrocephalosyndactyly An inherited disorder characterized by abnormalities of the skull, face, hands, and feet. It begins with premature closure of some sutures of the skull (craniosynostosis) and results in a tall peaked head, shallow eye sockets, and underdeveloped cheekbones. With acrocephalosyndactyly, fingers and toes are fused (syndactyly), and the thumbs and big toes have broad…

acrocentric chromosome A chromosome in which the centromere is located quite near one end of the chromosome. Humans normally have five pairs of acrocentric chromosomes. Down syndrome is caused by an extra acrocentric chromosome (chromosome 21).

acquired mutation A genetic change that occurs in a single cell after the conception of an individual. That change is then passed along to all cells descended from that cell. Acquired mutations are involved in the development of cancer.

acquired immunodeficiency disease See AIDS.

acquired Not inherited, or present at birth (congenital), but developing after birth. For example, AIDS is an acquired, not an inherited, form of immune deficiency.

acoustic nerve The eighth cranial nerve which is concerned with hearing, balance, and head position. It branches into two parts—a cochlear part that transmits sound reception for hearing and a vestibular part that senses balance and head position. Also known as the vestibulocochlear nerve.

ACOG American College of Obstetricians and Gynecologists, a professional organization for women’s health care providers that also does advocacy work to improve the care of female patients.

acne vulgaris The common form of acne, in teens and young adults, that is due to overactivity of the oil (sebaceous) glands in the skin that become plugged and inflamed. Acne typically develops when the oil glands come to life around puberty and are stimulated by male hormones that are produced in the adrenal glands…

acne rosacea See rosacea.

acne Localized skin inflammation resulting from overactivity of the oil glands at the base of hair follicles or as a response to contact with irritating substances. See also acne vulgaris.

ACL Anterior cruciate ligament.