Long-Term Treatment of Lipoprotein Lipase Deficiency with Medium-Chain Triglyceride-Enriched Diet: A Case Series

Background: Lipoprotein lipase (LPL) deficiency is a genetic condition. Affected individuals typically develop symptoms related to severe and persistent hypertriglyceridemia, such as abdominal pain and recurrent pancreatitis, before 10 years of age. No pharmacological treatment sustainably lowering triglycerides (TGs) in LPL deficiency patients has been proven to be effective. This study investigated whether a long-chain triglyceride (LCT)-restricted, medium-chain triglyceride (MCT)-supplemented diet enables a meaningful reduction in TGs and reduces LPL-related symptoms in children with LPL deficiency. Methods: A single-center retrospective case series study of LPL deficiency patients treated at the Hospital of Sick Children between January 2000 and December 2022 was carried out. Data, extracted from hospital charts, included demographics, diagnosis confirmation, clinical and imaging observations, and biochemical profiles. Results: Seven patients with hypertriglyceridemia > 20 mmol/L suspected of an LPL deficiency diagnosis were included. Six patients had a confirmed molecular diagnosis of LPL deficiency, and one had glycogen storage disease type 1a (GSD1a). Clinical presentation was at a median of 30 days of age (range 1-105), and treatment start, excluding one late-treated patient, was at a median of 42 days (range 2-106). The observation and treatment period of the LPL patients was 48.0 patient years (median 7.1, range 4.3-15.5). The LCT-restricted and MCT-supplemented diet led to an immediate drop in TGs in six out of six LPL patients. TGs improved from a median of 40.9 mmol/L (range 11.4-276.5) pre-treatment to a median of 12.0 mmol/L (range 1.1-36.6) during treatment, total cholesterol from 7.6 mmol/L (4.9-27.0) to 3.9 mmol/L (1.7-8.2), and pancreatic lipase from 631 IU/L (30-1200) to 26.5 IU/L (5-289). In 48 patient years, there was only one complication of pancreatitis and no other disease-specific manifestations or complications. Catch-up growth was observed in one late-treated patient. All patients maintained normal growth and development. As expected, the diet failed to treat hypertriglyceridemia in the GSD1a patient. Conclusions: The dietary restriction of LCT in combination with MCT supplementation as long-term management of pediatric patients with LPL deficiency was feasible, well tolerated, and clinically effective in reducing TG levels and in preventing LPL-related complications.