A case of dyskeratosis congenita associated with impaired DNA repair as shown by the comet assay. 
An 18-year old boy with dyskeratosis congenita is presented.  To examine the DNA metabolism of our patient, we applied the comet assay, a simple, quick and sensitive method that so far has not been used in this disease.  After exposure to UVB, cells originating from the patient present abnormal DNA repair localized in the late step.  We consider that such repair deficiency could be related to susceptibility to cancer.  The comet assay seems to be a good procedure to investigate dyskeratosis congenita or other genodermatoses.