Melanocytes and Disorders of Pigmentation Flashcards
normal skin color results from a what?
MELANIN, hemoglobin and carotenoid
What is ceruloderm?
a gray, slate or blue discoloration that arises from an increase in the # of melanocytes
Where can melonoma be present?
skin, ear, brain or eye
What does the C-KIT gene encode?
a receptor for steel factor
What is the binding of C-KIT to steel factor important?
It is critical for melanocyte migration and proliferation
Where do melanocytes reside?
basal layer
What is the key enzyme in melanin biosynthesis?
tyrosinase
What are the two major forms of melanin?
Eumelanin–> brown-black
pheomelanin–> yellow-red
What is the major factor in pheomelanogenesis?
mutation of MC1-R
Describe common features of vitiligo
autoimmune inflammatory disease–> destruction of melanocytes
keobnerization
What is the treatment for vililigo?
photoprotection, topical steroids and phototherapy (and grafting)
Describe common features of piebaldism
autosomal dominant
white forelock of hair
depigmentation involving the midline
What disease results from mutation of the c-KIT gene?
Piebaldism
Describe common features of Pityriasis Alba
ill-defined round patches, sometimes with overlying scale
common among children and those with atopic dermatitis
What defect commonly causes albinism?
tyrosinase
