Cardiomyopathies, particularly hypertrophic cardiomyopathy, are common and can be associated with various IMDs, including hereditary haemochromatosis, Fabry disease, Pompe disease, Danon disease, Friedreich’s ataxia, mitochondrial disorders, very long-chain acyl-CoA dehydrogenase deficiency, and carnitine palmitoyltransferase II deficiency. Here, CPT2 is linked to hyperinsulinemic hypoglycemia, familial, 4.