Pigment Disorders B&B

Question 1

melanin is synthesized from which amino acid?

Answer 1

tyrosine

Question 2

melanocytes are derived from which embryonic origin?

Answer 2

neural crest

Question 3

the most common forms of albinism are due to…

Answer 3

decreased activity of tyrosinase (recall melanin is derived from tyrosine)

normal number of melanocytes but reduced melanin synthesis

Question 4

melasma

Answer 4

acquired hyperpigmentation of the face (often symmetrical) in sun-exposed areas

most common in women with dark complexions, onset is often with pregnancy or oral contraceptives (may be due to higher estrogen)

triggered by UV light in susceptible women —> increased melanin synthesis

Question 5

what occurs in vitiligo?

Answer 5

acquired, localized autoimmune destruction of melanocytes

can treat with steroids or immunosuppressants