Colorectal cancer (CRC) occurs both as a part of recognized heritable syndromes and in the form of "sporadic" disease.
Ionizing radiation to the head and selected heritable syndromes are established risk factors (Fisher et al. 2007).
Heritable syndromes are the only established causes, but these account for a minority of cases (Bondy et al, 1991).
This trend in mutation prevalence with time from initial gene discovery is typical for many heritable syndromes as more probands without family histories and without full phenotype are analyzed, thus making molecular diagnosis difficult and predictive testing challenging, often impossible.
Aetiology for sarcoma development has not been fully established; however, variations between ethnic groups in the incidence of rhabdomyosarcoma and fibrosarcoma, together with their occurrence in a number of heritable syndromes, suggest that genetic predisposition is important [ 4].
Approximately 3% of all PCs are associated with SDH deficiency (Gill et al. 2010 b ) and occur as part of PGL1 and PGL4; except for negative SDHB immunohistochemistry (discussed in detail below), these are otherwise histologically indistinguishable from sporadic PCs or from PCs associated with other heritable syndromes (e.g. multiple endocrine neoplasia type 2 (MEN2), VHL and NF).
Degenerative suspensory ligament desmitis (DSLD) is a heritable, debilitating syndrome recognized in Peruvian Pasos, Peruvian Paso crosses, Arabians, American Saddlebreds, American Quarter Horses, Thoroughbreds, and some European breeds [ 12].
They argue that having a heritable cancer syndrome in the family is something they cannot influence themselves, but are unfortunately confronted with.
Psychosocial workers, who usually counsel patients who experience difficulty in making decisions, expressed their concerns about the complexity of decisions that patients have to make and the psychological burden of knowing to carry a mutation for a heritable cancer syndrome.
