- Failure to develop. If something develops and then wastes away, that is atrophy.
* * *1. Defective development or congenital absence of an organ or tissue. 2. In hematology, incomplete, retarded, or defective development, or cessation of the usual regenerative process. [G. a- priv. + plasis, a molding]- a. cutis congenita [MIM*107600, *207700, *207730] congenital absence or deficiency of a localized area of skin, with the base of the defect covered by a thin translucent membrane; most often a single area near the vertex of the scalp, but may occur in other areas; underlying structures may also be affected; autosomal inheritance, either dominant or recessive.- gonadal a. congenital absence of essentially all gonadal tissue; the external genitalia and genital ducts are female, but if interstitial cells of Leydig are present, the external genitalia are commonly ambiguous and the genital ducts are female. SEE ALSO: gonadal dysgenesis, gonadal agenesis. Cf.:Klinefelter syndrome, Turner syndrome.- pure red cell a. a transitory arrest of red blood cell production which may occur in the course of a hemolytic anemia, often preceded by infection, or as a complication of certain drugs; if the arrest persists, severe anemia may result. SEE ALSO: congenital hypoplastic anemia.
* * *apla·sia (')ā-'plā-zh(ē)ə, ə- n incomplete or faulty development of an organ or part
* * *n.total or partial failure of development of an organ or tissue. See also agenesis.• aplastic adj.
* * *apla·sia (ə-plaґzhə) [a-1 + -plasia] lack of development of an organ or tissue. Cf. agenesis and hypoplasia.
Medical dictionary. 2011.