- An autosomal recessive condition present in individuals in two or more generations of a family, thereby appearing to follow a dominant inheritance pattern. Common explanations include: 1) a high carrier frequency; 2) birth of an affected child to an affected individual and a genetically related (consanguineous) reproductive partner.
Definition from: GeneReviews
from the University of Washington and the National Center for Biotechnology Information
See also Understanding Medical Terminology.