Hello and thanks for posting your question here. The most probable cause of high TG levels in your baby seems congenital hypothyroidism so I would request you to visit pediatrician immediately and get his blood investigations done to confirm the diagnosis so that treatment could be started without any delay as hypothyroidism is known to have nervous sytem manifestations. But other cause of high TG levels also need to be ruled out like Familial hypertriglyceridemia which is a congenital condition due to the deficiency of an enzyme LIPOPROTEIN LIPASE which is required for the metabolism of the TG. Now as you said that both parents have normal lipid profile, this could be because this disorder is autosomal recessive. So both the parents may be career for this disorder. Having high TG levels is a risk factor for pancreatitis and vascular atherosclerosis that is deposition of lipids in the vessel walls of heart, CNS and other blood vessels. SO it is very important to keep the TG levels within normal range once the cause is established. I hope this would help you.