The review of the literature shows that CCLD is a multifactorial disease, but nonetheless also a genetic disease. Mostly pure breeds are affected, the top breeds affected with CCLD are Newfoundland, Rottweiler and Labrador retriever. Bilateral ruptures are very common, this points in the direction of a premature pathological degenerative disease, which one expects with an inherited disease, most ruptures are chronic ruptures, not acute-injury or trauma induced, the ruptures occur within normal activity-level. Most ruptures occur at too young of an age for it be explained by physiological aging process. The mean age of CCLR is reported to be between 4,3 -7,7 in the different published studies.