Collagens, the basic proteins of the human body.

Collagens are structural elements of many tissues in the human body. The family of collagens can be divided into fibrillar and non-fibrillar collagens. The criterion of the classification is the structure of these proteins. Mutations in the genes encoding collagens cause a variety of human diseases that include osteogenesis imperfecta, some forms of osteoporosis, chondrodysplasias, some types of Ehlers-Danlos syndrome, arterial and intracranial aneurysms, epidermolysis bullosa and the renal disease known as Alport syndrome. The detection of mutations is important both scientifically and clinically. Defining the molecular defects underlying a disorder helps in the understanding of not only the properties of the mutated protein but also the function of the normal protein. Even though many mutations in the genes encoding collagens have been described, the pathogenic consequences of some of the mutations are not fully understood. The important rationale for mutation detection is the clinical use of molecular diagnostics in genetic counselling and differential diagnosis.