Type I hyperlipidaemia caused by lipoprotein lipase deficiency in a nurseling: the role of the clinical laboratory in processing biological samples and contributing to the diagnosis and therapeutic follow-up of patients.

We describe the case of a two-months-old nurseling admitted to the paediatric emergency unit for vomiting. Upon clinical examination, the paediatrician found the child pale with an alteration of the general condition, a tachycardia and severe hepatomegaly. Blood sampling revealed hyperlipasemia at 228 IU/L and lactescent plasma, prompting the biologist to complete the prescription by lipid profile analysis. Severe hypertriglyceridaemia peaking at 47 mmol/L was then identified. The hypothesis of acute pancreatitis due to familial chylomicronaemia was proposed. The diagnosis of type I hyperlipidaemia due to complete lipoprotein lipase deficiency was later confirmed by the molecular genetic identification of a homozygous mutation in the LPL gene encoding the enzyme. This disease is extremely rare, and occurrence of first clinical symptoms before one year of age is possible although exceptional. The treatment, including digestive rest and parenteral nutrition, allowed rapid improvement of the acute episode and long-term dietary management prevented recurrent acute pancreatitis. In addition to the importance of clinical and laboratory cooperation, this case report provides an opportunity for discussing the analytical interferences and pre-analytical procedures involved in the exploration of biological parameters in hyperlipaemic plasma.