The prevalence of carnitine defects and mitochondrial long chain fatty acid oxidation disorder (LCFAOD) in 1 clinic was 4.75%, a retrospective cohort according to a recent study.

The researchers set out to explore the genotypic and phenotypic spectrum of carnitine metabolism defects and mitochondrial long-chain fatty acid oxidation along with the corresponding treatment options.

There were a total of 38 patients with 7 different types of the diseases at the clinic, including 6 types of LCFAOD as well as multiple acyl-CoA dehydrogenase deficiency.

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The study was published in the Orphanet Journal of Rare Diseases.

Read more about the epidemiology of LCFAOD

The study team assessed patient charts by looking at biochemical investigations, molecular genetic investigations, neuroimaging, cardiac assessments, outcomes, treatments, and clinical features.

Statistically significant differences were reported for hypoglycemia and rhabdomyolysis in the cohort of patients diagnosed symptomatically compared to those diagnosed asymptomatically.

Furthermore, patients diagnosed symptomatically had a higher number of hospital admissions, stayed in the hospital for longer, and had higher levels of casein kinase in their serum, a marker of muscle damage, even though, they only represented about a third of all patients in this study.

“Asymptomatic diagnosis is important to improve quality of life and decrease acute complications,” the study authors noted.

They identified 28 variants in 7 genes in 36 patients, of which 25 were pathogenic or likely pathogenic, 3 were of unknown significance, and 4 were novel.

There were 14 patients, who were diagnosed symptomatically, and 24 who were diagnosed asymptomatically. The asymptomatic cohort was diagnosed based on either newborn screening or a positive family history.

All 4 patients with long chain 3-hydroxyacyl-CoA dehydrogenase deficiency had the common variant p.Glu474Gln in the HADHA gene and a similar phenotype to what is reported in the literature.

However, only 1 of the 5 patients with very long-chain acyl-CoA dehydrogenase deficiency had the common p.Val283Ala in the ACADVL gene, but the different genotypes had similar phenotypes.

A total of 8 patients were treated with carnitine supplementation, whereas 13 patients were treated with a long-chain fat-restricted diet and medium-chain triglyceride supplementation. 


Ambrose A, Sheehan M, Bahl S, et al. Outcomes of mitochondrial long chain fatty acid oxidation and carnitine defects from a single center metabolic genetics clinic. Orphanet J Rare Dis. 2022;15;17(1):360. doi:10.1186/s13023-022-02512-5