If these others had scattered gray hairs in childhood, but did not progress to a full head of gray hair until later, then it is likely that your son would follow the same pattern. Gray hair can also accompany a number of uncommon familial syndromes, including neurofibromatosis and tuberous sclerosis. Several conditions can alter a child's preset melanocyte-clock. The most common of these is vitamin B12 deficiency. Vitamin B12, or cobalamin, is present widely in foods from animal sources.
Dietary deficiency is difficult to achieve, unless a person is eating a strict vegan diet.
Breast-fed infants whose mothers have B12 deficiency can also develop a transient deficiency. A lack of vitamin B12 can occur even in the face of adequate B12 intake. A simple blood test can diagnose current vitamin B12 deficiency. If your son was deficient in the past, it will probably not be detectable, but neither will the graying progress. A simple blood test detects current anemia.