It has been thought that individuals with Hailey-Hailey disease possess not one, but two or more genetically different populations of cells that originate from the one fertilized cell after fusion of the sperm and ovum during fertilization. This condition is known as mosaicism. In most cases of clinical mosaicism, the linear patterns of abnormal skin are surrounded by normal skin termed type 1 mosacism. Several patients have been described whom experience both patterned lesions and, in remaining areas of skin, also show a milder form of the disorder termed type 2 mosaicism.
In the November 15 issue of the Journal of Clinical Investigation, German researcher Jorge Frank and colleagues reveal the molecular basis of type 2 mosaicism in Hailey-Hailey disease. The authors isolated skin cells from severely affected areas of a female patient and found that skin cells from patterned skins lesions possessed a defect in the gene ATP2C1, which encodes a calcium pump protein, present on the chromosome derived from the patients mother. Normally, the chromosome obtained from the father and presumably containing a normal form of this gene, would compensate for this defect and result in the remaining skin cells being normal. However, in this case, the chromosome obtained from the father had been lost. Therefore, skin cells isolated from other areas of the skin possessed the same defect and in effect the patient had received a "double dose" of the mutant gene in severely affecte
Contact: Brooke Grindlinger
Journal of Clinical Investigation