xeroderma pigmentosum
Introduction
Introduction to xeroderma pigmentosum Xeroderma pigmentosum is an autosomal recessive hereditary skin disease with an incidence of about 1:250,000. It is characterized by DNA damage that cannot be repaired after UV irradiation. The patient is highly sensitive to daylight and has a photophobia. Skin atrophy in the exposed parts of the light, a large number of freckle-like pigments deepens the plaque, and then new organisms can be involved in many systems. Many patients may be accompanied by lesions such as the eyeball and nervous system. basic knowledge The proportion of illness: 0.004%-0.007% Susceptible people: no specific population Mode of infection: non-infectious Complications: freckles
Cause
Causes of xeroderma pigmentosum
Genetic factors (65%):
More common in human skin pigmentation, generally autosomal recessive inheritance, occasional recessive recessive inheritance, caused by DNA repair dysfunction caused by endonuclease deficiency, some genes heterozygous for freckle-like damage The patient has obvious allergic properties to sunlight, some are sensitive to the wavelength of 280-310 nm, and some are completely normal. Due to the long-term exposure of ultraviolet light, the DNA of the epidermal cell nucleus is damaged, and the epidermal fibroblasts completely or partially lack the repair function, resulting in the disease. Clinical manifestations, some patients may have amino acid urine, serum ketones increased.
The cell lacks endonuclease (15%):
The main biochemical defect of this disease is that the DNA in the skin part lacks the endonuclease, so the DNA damaged by sunlight can not be repaired normally. Since the onset of childhood, the family often has a history of close relatives marriage.
Prevention
Coloring dry skin disease prevention
1. Avoid marriage by close relatives. Prevent sun exposure.
2, reasonable diet, work and rest.
3, develop a good habit, quit smoking and alcohol, not alcohol. Smoke and alcohol are extremely acidic and acidic substances. People who smoke and drink for a long time can easily lead to acidic body.
Complication
Coloring dry skin disease complications Complications freckles
Generally no complications.
Symptom
Symptoms of xeroderma pigmentosum Common symptoms pigmented freckles, dry skin, pigmentation, scarring
From the beginning, there are freckles and dry skin on the exposed parts such as face, lips, conjunctiva, neck and calves. Similar to solar dermatitis, the skin begins to redden, and then there is persistent reticular telangiectasia. On the basis of erythema. Gray or gray-brown pigmented patches of varying sizes, freckle-like lesions or punctate pigmentation spots, sometimes showing scarring and bullous lesions, common verrucous keratinization, can resolve or worsen on their own, Malignant tumors within 3 to 4 years, mostly basal cell carcinoma, squamous cell carcinoma or melanoma, are multiple and can cause death due to extensive metastasis.
Hair and nails are normal, teeth can be defective, the disease often dies before the age of 10, 2/3 patients die before the age of 20, eye damage can be seen in 80% of patients, may have photophobia, eyelid valgus and chin Damage to the bulbar conjunctiva exposed, the conjunctiva may have pigmented spots, vascular pterygium, corneal opacity, poor development of the patient and small, many patients with significantly retarded intelligence.
Examine
Examination of pigmented dry skin disease
The early pathological changes are non-specific, and may be hyperkeratotic. The Malpyrine base layer is thinned with some skin processes atrophy and elongation intersecting each other. The metaphase part of the epidermis shows atrophy, interspersed with acanthosis, and the epidermal cell nucleus is disordered. The epidermis has atypical growth and its tissue resembles solar keratosis, and histological changes of various tumors can be seen in the late stage of the tumor.
Diagnosis
Diagnosis and identification of xeroderma pigmentosum
diagnosis
The typical case can be diagnosed according to the clinical, the early pathological changes are non-specific, and there may be hyperkeratosis. The Malpis base layer is thinned with some skin processes atrophy and elongation intersecting each other, and the mid-segment part of the epidermis shows atrophy with interstitial hypertrophy. The epidermal cell nucleus is disordered. In some areas, the epidermis grows atypically and its tissue resembles solar keratosis. The histological changes of various tumors can be seen in the advanced tumor stage.
Differential diagnosis
1. Freckles: Frequently on the face, it is a large gray or taupe spot on most cap needles, no skin keratosis, scars and cancer, and no telangiectasia.
2. Congenital skin heterochromia syndrome: skin atrophy in the face, neck, extremities, etc., brown-red pigmentation, telangiectasia, often accompanied by congenital cataract, dwarf, small head and so on.
