Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD) are conditions where the body struggles to use certain fats for energy. This study is about checking the long-term safety of people with LC-FAOD, especially focusing on women who are pregnant or breastfeeding. The study will last up to 10 years, gathering information from people who have been treated with a special fat called triheptanoin in the past or in other studies. Triheptanoin is not given directly by this study; instead, it can be accessed commercially or through other special programs if available in their country.

• The study lasts up to 10 years and involves both adults and children.
• Participants will be monitored by their doctors and may or may not use triheptanoin during the study.
• People with confirmed LC-FAOD willing to follow study rules and provide necessary permissions can participate.

Pregnant women can continue in the study to help understand how LC-FAOD affects pregnancy. However, if they have another disease or condition that the study doctor thinks might cause problems, they might not be able to join or stay in the study.