Background:
Long-Chain Fatty Acid Oxidation Disorders (LC-FAODs) are a group of six rare inherited metabolic conditions: CPT I, CPT II, CACT, LCHAD, TFP and VLCAD deficiencies. Together, they affect around one in 50,000 births. VLCAD is the most common, whereas CPT I, CPT II and CACT deficiencies are much rarer, with only one in several hundred thousand to two million births.

These conditions limit the body’s ability to break down long-chain fatty acids to produce energy, especially during fasting, illness or prolonged exercise. As a result, people with LC-FAODs are at risk of acute energy crises, which can be life-threatening.

Symptoms vary depending on the specific disorder and can appear from infancy to adulthood. Common issues include muscle weakness, hypoglycaemia and rhabdomyolysis (breakdown of muscle tissue), which may lead to kidney complications.

Current treatment focuses on preventing metabolic crises by following a fat-restricted diet and using medium-chain fatty acid supplements, which can be more easily converted into energy. A newer treatment, Triheptanoin (C7), is being investigated and is available in the UK through the Early Access to Medicines Scheme as an additional energy source for people with LC-FAOD.

Aim:
This piece of work aimed to capture and better understand the lived experience of people living with, caring for, or having cared for someone with an LC-FAOD. It included perspectives across most LC-FAOD types to reflect the breadth of this rare disease community. This work being used to inform the evidence base for the use of Triheptanoin.