It is known that UV irradiation exacerbates DD cutaneous lesions [2, 3]: this might partly be due to a direct modulation of keratinocytes by UV to produce proinflammatory cytokines such as interleukin (IL)-1, IL-6, IL-8 and tumour necrosis factor (TNF)-A [27], leading to skin inflammation. The gene discussed is TNF; the disease is dentin dysplasia.