A conceptual model illustrating the signs, symptoms, triggers, and impacts on the quality of life (QoL) of patients with long chain fatty acid oxidation disorders (LCFAODs) has been compiled utilizing the perspectives of patients, caregivers, and clinicians, as published in Therapeutic Advances in Endocrinology and Metabolism.

The conceptual model compiled 9 domains of signs and symptoms, 8 domains of the impacts on QoL, and 11 triggers of acute changes in symptoms reported by the participants. Participants reported signs and symptoms which affected multiple systems in the body including musculoskeletal, cardiovascular, gastrointestinal, urological, endocrine, and neurological systems as well as specifically affecting sensory, respiratory, and constitutional aspects of health.

“Findings support that LCFAOD are associated with a broad variety of serious signs and symptoms, such as muscle breakdown/rhabdomyolysis, low blood sugar/hypoglycemia, and cardiac and liver complications,” the authors said.

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A number of triggers for episodes of what participants called “metabolic crises” or “acute symptom episodes” were also reported. These triggers included prolonged exercise, acute illnesses, anesthetics, fasting, physiological stress, exposure to cold temperatures, hot weather, dehydration, a change in hormones/menstruation, lack of sleep, and psychological stress.

LCFAOD had numerous impacts on the quality of life of patients such as exercise intolerance, reduced mobility, and fatigue. These physical factors caused lifestyle modifications such as more focus on weight and diet management and possible reliance on a caregiver as well as reduced spontaneity in schedules because of a need to plan things in advance.

LCFAOD also affected daily activities such as self-care, housework, and traveling, while also causing school or work disturbances through missed days and limited career opportunities. Patients required more medical care such as hospitalization, feeding support, and medications which had financial impacts on patients.

“Patients also experience significant QoL impacts that affect all aspects of life from physical functioning, work/school, and sleep which are intensified by their monitoring of symptoms, diet, and exercise in attempts to avoid triggering and/or exacerbating symptoms,” the authors said.

During the study, an initial group of 4 patients and 4 caregivers were assembled into a focus group and represented patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (n=4), carnitine palmitoyltransferase II (CPTII) deficiency (n=3), and long-chain 3-hydroxy-acyl-CoA dehydrogenase (LCHAD) deficiency (n=1). The patients ranged in age from 21 to 60 years and the caregivers were all mothers of patients with LCFAODs.

An additional 4 patients (age range 15-59 years) and 1 mother of a 2-year old were also interviewed individually and represented VLCAD (n=2), LCHAD (n=2), and CPTII (n=1). Finally, 4 clinicians including a pediatrician specializing in metabolic disorders, a metabolic physician, and 2 geneticists who focus on clinical care and research were interviewed.


Williams-Hall R, Tinsley K, Kruger E, et al. Qualitative evaluation of the symptoms and quality of life impacts of long-chain fatty acid oxidation disorders. Ther Adv Endocrinol Metab. Published online January 10, 2022. doi:10.1177/20420188211065655