Nail defects reveal mechanisms for organ formation
[NEWS 10 June 2011] An international research consortium including teams from Uppsala University and Karolinska Institutet has identified the cause of serious defects in human finger and toenail formation as disrupted signalling between cells in the skin. Their finds are presented in the June issue of the American Journal of Human Genetics.
Our nails are formed from certain skin cells during the fetal stage through signalling from so-called WNT molecules. The study shows that the signals are received and re-transmitted through the agency of a protein called Frizzled 6, which ensures that the nails are properly formed and attached to the nail bed. If Frizzled 6 is absent or has reduced functionality the signals are not received, causing serious defects in nail formation.
In this present study, the researchers have identified individuals with this specific form of nail defect, whereby the nails are unusually thick but brittle and have shrunken nail beds. The nails are also loose and can spontaneously detach themselves, which limits the patients' ability to carry out manual labour. This defect is very rare but reveals the basic mechanisms of organ formation. The researchers also show that the mechanism is preserved in other animals. Mice with mutations in the gene for Frizzled 6 have defective claws that loosen easily.
The researchers believe that their findings add fundamental knowledge to the understanding of how the WNT signal system controls the formation and function of a specific body tissue, which is of potential medical significance in the treatment of some organ or cell-specific diseases.
Mutations in Frizzled 6 Cause Isolated Autosomal-Recessive Nail Dysplasia
The American Journal of Human Genetics, June 2011, doi:10.1016/j.ajhg.2011.05.013