health

The diagnosis of xeroderma pigmentosa is usually made during the
baby’s first or second year of life, often following a history of severe and
long-lasting sunburn following only brief exposure to sunlight, or heavy
freckling on the baby’s face. There is usually no family history of the disorder.
The doctor will, however, ask the parents about a family history of
intermarriage among relatives in the extended families on both sides, as
kinship marriages are a risk factor for genetic disorders.
The doctor will examine the baby for signs of eye problems,
including clouding of the cornea (the transparent covering of the front
of the eyeball that admits light) and skin tumors growing near the eyes.
The baby’s reflexes and coordination may also be tested. The diagnosis
of XP can be confirmed by genetic testing or by tests on skin cells that
evaluate whether the cells are unusually sensitive to ultraviolet light. These
tests can be performed only in highly specialized laboratories, however.
XP can be diagnosed before birth by amniocentesis or by chorionic
villus sampling (CVS). CVS is a test in which the doctor takes a small
sample of tissue from the placenta, the organ that forms inside the uterus
during pregnancy and links the mother’s blood supply with the baby’s
blood supply. The tissue sample can then be analyzed for evidence of a
genetic disorder.