18 Months of Treatment with Triheptanoin in 2 Patients with Long Chain Fatty Acid Oxidation Disorders

Long-chain fatty acid oxidation disorders (LC-FAOD) are inborn errors of metabolism, also identified in newborn screening in Portugal. They interfere with adequate energy utilization, namely by muscles, heart, and liver. Treatment aims to maintain patients in an anabolic state, with increased caloric intake, using carbohydrates and medium-chain fatty acids. Treatment with triheptanoin (THP), a synthetic seven-carbon fatty acid triglyceride compound with an anaplerotic effect that increases energy availability to the cell, has been advocated as an efficacious and safe therapy in LC-FAOD.

Retrospective revision of clinical records of 2 LC-FAOD patients comparing number, severity and admissions for rhabdomyolysis crises, maximum CK values and weight gain in a period of 18 months before and after treatment with THP.

Patient 1 is a 12 year old male with VLCADD, with main manifestation being rhabdomyolysis crises. After he started THP we found a decrease in admissions (6 to 2), less rhabdomyolysis crises treated at home (5 to 3), and lower maximum CK values (72352 U/L to 13.000U/L). He had a large increase in weight - 13kg in 18 months. He was able to start pool exercises with no rhabdomyolysis associated. Patient 2 is an 8 year old male with LCAHDD, with main manifestations being rhabdomyolysis crises and retinopathy. After he started THP we found a decrease in admissions (4 to 1), no rhabdomyolysis crises treated at home, and lower maximum CK values (100.000U/L to 19848 U/L). He also increased his weight - 7kg in 18 months. He plays football in school and swims with no rhabdomyolysis associated. In both patients, no major side effects were observed.

In our patients, we could observe a reduction in the number of admissions, and less severe rhabdomyolysis crises after THP use. The weight gain was significant. There were no major side effects. Despite regarding only two patients, our findings are in line with the latest literature on THP and LC-FAOD, reinforcing the utility of THP as one more tool in the treatment of these disorders with rhabdomyolysis as the main manifestation. The weight increase is an issue to be aware of and to address from the start of the treatment.