Xeroderma pigmentosum (De Sanctis-Cacchione syndrome)
Incidence
Rare AR disease. It is a DNA repair defect after UV radiation. There are neurological symptoms in 20% of pts. (De Sanctis-Cacchione syndrome), but in 90% of pts in Japan.
Clinical Characteristics
The main characteristics are dermatitis and skin cancer after exposure to sunlight. Neurological Sx occur in 20% of pts. but in 90% in Japan. This condition is considered a neurocutaneous syndrome or phakomatosis. Neurological symptoms start in late childhood or adolescence (usually between 7 and 12 years). The skin Sx occur after sun exposure, with abnormal erythema, edema, blistering. With repeated exposure, pyts develop irregular pigmentation, freckling, scarring and skin cancer of variable type. There is photophobia and conjuntival erythema to sun exposure. Also cutaneous atrophy, telangiectasias and ulceration occur. Some times developmental delay can be seen in infancy. The symptoms are progressive mental deterioration, microcephaly, sensorineural deafness, dysarthria, choreoathetosis, ataxia, peripheral axonal polyneuropathy, Seizures may occur. FTT, eventually pyramidal Sx with spastic quadriparesis. There may be endocrine abnormalities associated. Pts often look like pts with Cockayne syndrome but there is no leukodystrophy and no intracranial calcification. Pts with XP have also a tendency to develop skin cancer.
Precipitants
There is dermatitis and skin cancer after exposure to sunlight.
Provocation Tests
no
Diagnostic Procedures
Clinical Dx.