xeroderma pigmentosum
a syndrome acquired as an autosomal recessive trait (see recessive allele) and marked by extreme photosensitivity. It is caused by a defect in the ability of the body to repair damage to DNA resulting from exposure to ultraviolet light, which leads to cancerous changes in skin cells and increased mortality. Additionally, about 30% of people with this syndrome develop progressive neurological symptoms, including hearing loss, movement problems, loss of intellectual function, and seizures.