A syndrome characterized by a defect in ultraviolet
radiation-induced DNA repair mechanisms and by a severe sensitivity to all
sources of ultraviolet radiation (especially sunlight). XP is categorized into
seven complementation groups according to the capacity of the body to repair DNA.
Life-threatening. The DNA damage is cumulative and irreversible. Sometimes
lethal in infancy or childhood.
Xerodermic Idiocy; Kaposi Disease.
A group of rare autosomal recessive inherited disorders
that were first described by Ferdinand Ritter von Hebra, Austrian
dermatologist, and Moritz Kohn Kaposi, Hungarian dermatologist, in 1874.
1:250,000 in general population; higher in Japan
(1:40,000). Sex ratio is about 1.
A rare autosomal recessive genetic defect.
Caused by a defect in nucleotide excision repair
(NER), leading to an inability to repair DNA damaged by ultraviolet radiation.
There are two types of NER: global genome (GG-NER) and transcription coupled
(TC-NER). There are seven XP repair genes (XPA to XPG), with seven principal
complementation groups of XP corresponding to defects (four other
subcategories have been described). Frequency and severity varies among
forms; XPA and XPC are the most common.
Clinically evocated by the skin lesions with a
three-stage evolution. Skin is normal at birth. After the age of 6
months, a diffuse erythema, scaling, and freckle-like areas of increased
pigmentation, initially on the face can be seen. The second stage is characterized
by poikiloderma and the third stage by the appearance of numerous malignancies.
Diagnosis may be suspected and can be made during the first stage. It is
confirmed in vitro and by a skin biopsy.
Normally, it involves the skin
(photosensitivity, skin hypoplasia, increased patchy skin pigmentation, decreased
or increased irregular skin pigmentation, hyperkeratosis, hemangioma capillary,
telangiectasia skin, neoplasia), eyes (photophobia, optic disc atrophy,
conjunctival telangiectasia, paresis of ocular muscles), and CNS (more
common in XPA and XPD: e.g., abnormality, seizures, areflexia, cerebral cortex
atrophy, microcephaly, deafness, and mental retardation). Other possible features
include ectopic testes and teeth anomalies.
Evaluate the neurological function
(clinical, electroencephalogram, CT) and ocular lesions. Avoid radiographs because
Patient behavior in the operating room
may be affected by photophobia. It is recommended to dim the light. As with other
dermatological illness, intraoperative padding (pressure points) and positioning is
very important. Difficult airway management is possible because of skin atrophy,
scarring and macroglossia.
The use of inhalational agents is questioned because of their potential interaction
with the NER in cells of patients affected with XP, worsening the symptoms of the
disease. The interaction between anesthetic drugs and
antiepileptic treatment must be considered. Special attention must be given to the
administration of new medications and their
photosensitivity properties (e.g., antibiotics) medications that might affect
DNA must be avoided.
De Santis Caccione Syndrome: This
particular syndrome is usually present in xeroderma pigmentosum group A, and
shows, in addition to XP, ...