Can carnitine deficiency have adult onset or become symptomatic in a normal healthy person? if so what would cause it, liver is fine. pregnancy, diet?

Yes : Primary carnitine deficiency is an autosomal recessive disorder, with onset in infants, children or adults. In adults it usually occurs after a fast. The initial diagnostic lab is a plasma carnitine level. Some cases require more sophisticated tests. There are many other causes of carnitine deficiency, however, the most common in adults being an adverse side effect of statins. Why do you ask?