XERODERMA PIGMENTOSUM

Description:

Inherited condition characterized by an extreme sensitivity to ultraviolet (UV) rays from sunlight

Symptoms:

  • Areas exposed to the sun affected
  • Reddening of the skin with scaling and freckling
  • Irregular dark spots
  • Sunburn that does not heal after just a little bit of sun exposure
  • Blistering after just a little bit of sun exposure
  • Spider-like blood vessels under the skin
  • Patches of discolored skin that gets worse
  • Crusting of the skin
  • Scaling of the skin
  • Oozing raw skin surface
  • Discomfort when being in bright light (photophobia)
  • Skin cancer
  • Xerosis (dry skin)
  • Poikiloderma
  • Hypopigmentation
  • Skin cancers
  • Conjunctival inflammation and keratitis
  • Tumours of conjunctiva and eyelids
  • Eyelids may be pigmented, may lose lashes, or may atrophy
  • Unusually slow development, dwarfism, mental retardation, and neurological impairments
  • sensorineural deafness,
  • Spasticity, poor co-ordination, seizures
  • Acquired microcephaly or progressive intellectual impairment

Causes:

  • Autosomal recessive disorder
  • Basic defect in xeroderma pigmentosum- nucleotide excision repair
  • Deficient repair of DNA damaged by UV radiation

Risk Factors:

  • Age: The disease is usually detected at age 1-2 years
  • Race: Cases of xeroderma pigmentosum are reported in persons of all races
  • Gender: An equal prevalence in males & females.

Diagnostic Tests:

  • Amniocentesis (prenatally)
  • Careful skin examination
  • Eye examinations by an ophthalmologist
  • Routine neurologic evaluation
  • Genetic testing for mutations
  • Skin biopsy with fibroblast culture
  • Functional tests on living cells -to screen for abnormalities in DNA repair

Differential Diagnosis:

  • Congenital erythropoietic porphyria
  • Cockayne’s syndrome
  • XP-CS complex
  • trichothiodystrophy (TTD)
  • XP-TTD complex
  • cerebro-oculo-facio-skeletal (COFS) syndrome
  • UV-sensitive syndrome
  • Acanthosis Nigricans
  • Acute Cutaneous Lupus Erythematosus (ACLE)
  • Basal cell nevus syndrome
  • Bloom Syndrome (Congenital Telangiectatic Erythema)
  • Ephelides (Freckles)
  • Genetics of Cockayne Syndrome
  • Hartnup Disease
  • Hydroa Vacciniforme
  • LEOPARD Syndrome
  • Porphyria Overview
  • Rothmund-Thomson Syndrome
  • Werner Syndrome

Treatments:

  • Dermabrasion or dermatome shaving
  • cryotherapy
  • Skin grafting
  • Corneal transplantation
  • Avoidance of smoking
  • Genetic counselling

Medications:

  • Vitamin D supplements
  • Emollients for dry skin
  • Artificial tears for dry eyes
  • Oral isotretinoin may prevent new neoplasms
  • Repair of UV photolesions in XP group C cells
  • Actinic keratoses may be treated by cryotherapy or 5-fluorouracil cream

Lifestyle Management:

  • Wearing protective clothing
  • Using high protection (SPF 70 or greater) sunscreen
  • Using very dark, UV sunglasses
  • Constant educating and reminding of the need to protect oneself from sunlight
  • Genetic counseling for persons with a family history
  • Yearly testing (through to age 20) for potential neurological problems
  • Limiting time outdoors during daylight hours
  • Using special (e.g., broad-spectrum) topical sunscreens
  • Wearing sunglasses and double layers of clothing
  • Shielding glass in windows to prevent the passage of sunlight