03-13-2010, 01:42 AM
A 14 year old man presents to your office complaining of easy bruising. Physical examination reveals soft and loose skin and multiple ecchymoses in the forearm and pretibial region. Histological evaluation and electron microscopy shows collagen fibrils that are abnormally thin and irregular. Biochemical evaluation reveals abundant terminal disulfide bonds. Which of the following stages of collagen synthesis are most likely impaired in this patient?
a. RNA signal sequence recognition
b. Amino acid incorporation into polypeptide chains
c. Tripple helix formation
d. Lysine residue hydroxylation
e. Extracellular cleavage
a. RNA signal sequence recognition
b. Amino acid incorporation into polypeptide chains
c. Tripple helix formation
d. Lysine residue hydroxylation
e. Extracellular cleavage