Triglyceride metabolism was studied in a 14-month-old cretin boy. Prior to therapy, the child was found to have hypertriglyceridemia, hypercholesterolemia, and increased plasma pre-beta lipoproteins. An abnormality in lipoprotein lipase was suggested by low postheparin lipase activity (PHLA) in the child's plasma.
With 13 weeks of therapy, the triglyceride level fell and the lipoprotein distribution and PHLA in fasting plasma became normal. By 20 weeks, all lipid measures were normal. After only five weeks of thyroid replacement and improved oral intake, a paradoxical increase in plasma triglyceride and appearance of chylomicrons occurred despite a marked increase in PHLA.
Baum D, Guthrie R, Brunzell JD, Vogel WC, Bierman EL. Triglyceride Abnormality in Infantile Hypothyroidism. Am J Dis Child. 1973;125(4):612-613. doi:10.1001/archpedi.1973.04160040106023