GROUP 4

XERODERMA PIGMENTOSUM

INTRODUCTION

Xeroderma pigmentosum, or XP, is an autosomal recessive genetic disorder of DNA repair in which the ability to repair damage caused by ultraviolet (UV) light is deficient.

NORMAL CONDITION without XP

Exposure to UV light Thymine dimer No replicating DNA strand DNA DAMAGES Exposure to UV light Thymine dimer No replicating DNA strand

Nucleotide excision repair REPAIR SYSTEM Nucleotide excision repair Recognization Unwinding Cleavage Filling Sealing

ABNORMAL

NUCLEOTIDE EXCISION REPAIR Uvr-ABC excinuclease DNA Polymerase DNA Ligase skin GENE

SKIN UV The POL H gene (encoded DNA polymerase eta (Pol η)) Xeroderma pigmentosum protecting cells from UV thatinduced DNA damage fix DNA damage

Type of XP & inherited mutation gene Type A, I, XPA Type E, V, XPE Type B, II, XPB Type F, VI, XPF Type of XP & inherited mutation gene Type C, III, XPC Type G, VII, XPG Type D, IV, XPD Type V, XPV

autosomal recessive genetic disorder of DNA repair

Signs and Symptoms of Xeroderma Pigmentosum

Severe sunburn when exposed to small amounts of sunlight Severe sunburn when exposed to small amounts of sunlight. These often occur during a child's first exposure to sunlight. Development of many freckles at an early age  Skin Cancer Eyes that are painfully sensitive to the sun and may easily become irritated and bloodshot

Blistering on minimum sun exposure  Spidery blood vessels Scaly and dry skin Irregular dark spots on the skin

Bloodshot freckles blister blister Scaly skin

DIAGNOSIS Usually detected in early infancy 1-2 years Clue to diagnosis - severe sunburn after first exposure to the sunlight The diagnosis of XP is made on the basis of clinical findings and family history The diagnosis of XP is based on skin, eye, and nervous system XP can be diagnosed by measuring the DNA repair factor from skin or blood sample

Prompt removal of cancerous tissue B L E Treatment For XP Protection from UV Eye and skin exam Prompt removal of cancerous tissue Neurological exam Psychososial care

PrOGNOsi$ *Many patients die at an early age from skin cancers.but,if a person is diagnosed early, does not have severe neurological symptoms and takes all the precautionary measures to avoid exposure to UV light, they may survive beyond middle age. < 40% of individuals with the disease survive beyond age 20. Some with less severe cases manage to live well into their 40s

CONCLUSION

THANK YOU