COL17A1 and rickets: In addition, while a state of hypovitaminosis D was found in the majority of analyzed healthy individuals irrespective of anti-BP180-NC16A autoantibody reactivity, the rate of vitamin D deficiency, defined as < 20 ng/ml according to the Endocrine Society [10], was approximately twice as high in anti-BP180-NC16A IgG-positive compared to anti-BP180-NC16A IgG-negative healthy individuals (24% vs. 13%, respectively) (Fig. 1).