A 2-year-olds child is hospitalized for evaluation of poor growth and low muscle tone. The most striking physical finding is unruly, “kinky” hair, but the child also has increased joint laxity and thin skin. Which of the following laboratory findings is most likely?
a. High ceruloplasmin
b. High serum copper
c. Low serum iron
d. Low saturation of transferrin
e. Low serum haptoglobin