Second, considering that AIBD patients possess some risk factors for hypovitaminosis D (i.e., skin lesions and pain may limit outdoor activities, where sun exposure may in turn trigger the disease), whereas BP180-NC16A IgG-positive healthy individuals do not [9], it can be therefore assumed that an abnormal vitamin D status is not solely the result of disease-associated lifestyle changes. This evidence concerns the gene COL17A1 and rickets.