OBJECTIVES: Long-chain fatty acid oxidation disorders (LC-FAODs) are a group of rare inborn errors of metabolism which cause patients to experience acute metabolic crises. The physiological and biochemical signs and symptoms of LC-FAOD (including rhabdomyolysis, hypoglycemia and cardiomyopathy) are well documented in the literature; however, insight from the patient perspective is lacking. The aim of this study was to explore the experience of LC-FAOD from the perspective of individuals with LC-FAOD and caregivers of patients.

METHODS: A focus group (n=8) and concept elicitation interviews (n=6) were conducted, using a semi-structured interview guide, with patients and caregivers of patients to explore the symptoms and functional/quality of life impacts associated with LC-FAOD. To enrich understanding among LC-FAOD, a supplementary review of patient blogs/forums (n=17) identified from online searches was also conducted. Data were analysed using thematic analysis.

RESULTS: A wide range of signs and symptoms were experienced by patients with LC-FAOD (14 days-60 years old), and are broadly categorised into nine domains: musculoskeletal, neurological, gastrointestinal/digestive, sensory, developmental, cardiovascular, respiratory, urological and other. Muscle pain and tightness were described by patients as their ‘worst’ symptoms due to the uncontrollable nature of pain and resulting impacts on daily life. All symptoms reported were typically episodic in presentation (often associated with prolonged exercise, fasting and physiological stress, but also with no clear trigger) and reportedly led to periods of hospitalisation and clinical complications. LC-FAOD also affected patient’s emotional/psychological wellbeing, physical functioning, daily activities, social functioning and resulted in significant lifestyle modifications, such as dietary and exercise restrictions.

CONCLUSIONS: Using a multi-method and multi-perspective approach, this study provides comprehensive insight into the broad array of symptoms and considerable quality of life impacts of those living with LC-FAOD. Future research should explore the experience of LC-FAOD across different age groups and LC-FAOD sub-types.