Siblings with xeroderma pigmentosum complementation group A with different skin cancer development: importance of sun protection at an early age.

Abstract

For patients with xeroderma pigmentosum (XP), strict protection from UV light exposure is the only way to prevent and retard skin cancer formation. Our purpose was to learn how the timing of sun protection influences the clinical findings in patients with XP. We studied two siblings with XP group A (XPA) who showed a significant difference in the age at onset of skin cancer development and in neurologic abnormalities. The elder sister had had her first basal cell carcinoma (BCC) at 13 years of age and had had multiple BCCs by 25 years of age. Her younger sister had her first BCC at 23 years of age. Neurologic impairment of the younger sister was much milder. The elder sister started strict sun protection at 4 years of age, whereas the younger began at 2 years of age. Analysis of the XPA complementing gene revealed that both patients had the identical mutation. In patients with XP the earlier sun protection begins the later skin cancer develops. Neurologic deterioration may also be reduced by earlier sun protection.