Nail changes in genodermatoses.

Nail changes may be marker lesions for complex systemic disorders and herald associated syndromes. Knowledge of the anatomy, embryology and biochemical properties of the nail apparatus is essential for understanding the pathogenesis of hereditary nail disorders. In the last few years significant progress has been made in the field of clinical and molecular pathology of human diseases. A considerable number of the genes responsible for genodermatoses have been identified. The homeobox master control genes, genes encoding for transcription factors, genes encoding for the maintenance of telomeres, or for structural molecules, such as the similarly evolutionary highly conserved a-helical rod domains of keratins, are involved in the embryogenesis and normal functioning of nails. Using nail changes in selected genodermatoses with a known genetic background, we try to elucidate the genesis of inherited nail disorders and review the resultant clinical manifestations.