A syndrome of wide spaced eyes (ocular hypertelorism), front-facing (anteverted) nostrils, a broad upper lip, a malformed («saddle-bag») scrotum, and laxity of the ligaments resulting in bending back of the knees (genu recurvatum), flat feet, and overly extensible fingers. There are X-linked and autosomal forms of the disease. The gene for the X-linked form has been mapped to chromosome band Xp11.21 and identified as the FGD1 gene.

T cells that express the CD8 transmembrane glycoprotein (CD8+ T cells). They close down the immune response after invading organisms are destroyed. Suppressor T cells are sensitive to high concentrations of circulating lymphokine hormones, and release their own lymphokines after an immune response has achieved its goal. This signals all other immune-system participants to cease their attack. Some memory B-cells remain after this signal to ward off a repeat attack by the invading organism. Also known as T-8 cells.

Multiple copies of the same DNA base sequence on a chromosome; used as a marker in physical mapping of the chromosome.

Alzheimer disease that runs in families and strikes at an unusually early age (with its onset under the age of 60). About 7% of early-onset cases of Alzheimer’s are familial and are inherited in an autosomal dominant manner with high penetrance.