Arfgengur

Arfgengur is an Icelandic adjective meaning hereditary or inherited, used to describe traits, diseases, or characteristics that are transmitted from one generation to the next through genetic material. In medical and scientific discourse, arfgengur describes attributes whose origin lies in the genome rather than in environmental factors. The related noun arfgengi means heredity or inheritance in general, and it is used to discuss how traits or diseases pass through families.

Common phrases include arfgengur sjúkdómur (an inherited disease), arfgengur eiginleiki (a hereditary trait), and arfgengi fjölskyldu (family heredity). The term is used alongside more technical terms such as erfðafræði (genetics) and erfðafólk (hereditary lineage). In practice, arfgengi encompasses various inheritance patterns, including autosomal dominant and recessive, X-linked, and mitochondrial inheritance, as well as more complex polygenic traits. However, real-world inheritance can involve incomplete penetrance, variable expressivity, and gene–environment interactions, making prognosis and risk assessment probabilistic rather than deterministic.

In Icelandic scientific and medical writing, arfgengur is a standard descriptor for conditions known to be genetic in origin, and it is distinguished from non-genetic or acquired conditions. If used in lay language, it conveys that a trait or disease runs in families and is largely determined by heredity. This basic usage helps readers understand risk in family history and in genetic counseling contexts.