110 is quite low. How old is your son?

Cholesterol synthesis is controlled by genetics and the liver.
Food sources shut down the liver if excessive, and if food sources of cholesterol are limited, then the liver makes more.

As people age, their cholesterol goes up.
I think 150 lbs for a person 6foot 3 is very low weight.
If this is just genetic, that he is this thin, then that is it.

What are the cholesterol readings for the rest of the adults in your family?
It just might be that your son will catch up as he ages.
Cholesterol is a precursor to the manufacture of hormones in the body, and
is probably being used up rapidly as your son had this growth spurt.
After about age 25, he might see that number change.

Was the reading done fasting? that is also important. If it were after a meal
even 3-4 hrs after, it should be higher.

If you are concerned...time for some Omega-3 eggs for breakfast. But I wouldn't worry yet.