Also found in: Acronyms, Wikipedia.
X-linked recessiveGenetics adjective Referring to a mode of inheritance, in which a gene on the X chromosome requires one copy for phenotypic expression in ♂, but 2 copies for expression in ♀; with the gene only on the X chromosome, ♀ are carriers; ♂ get the disease. Cf Autosomal dominant, Autosomal recessive.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
X-linked recessivePertaining to a gene situated on an X chromosome which is expressed if the chromosome is carried on both X chromosomes in a female (which is necessarily rare). In males, however, the Y chromosome carries little or no genetic material and does not contain the normal ALLELE, so the gene on the X chromosome will always manifest itself. An X-linked recessive condition will thus usually occur only in males (who have one X and one Y chromosome) but cannot be transmitted by a father to his son because the son receives only the Y chromosome. The characteristic is, however, transmitted via the daughters, who are carriers. Their sons have a 50/50 chance of acquiring the X chromosome and manifesting the characteristic.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005