Delayed diagnosis of carnitine palmitoyltransferase II deficiency in a 63-year-old man with recurrent rhabdomyolysis: a case report

Carnitine palmitoyltransferase II (CPT II) deficiency is one of the important inherited disorders of long-chain fatty acid oxidation presenting in adulthood and is characterized by recurrent episodes of rhabdomyolysis, muscle pain, and transient muscle weakness. Because clinical manifestations are episodic and neurological examination and electromyography findings may be normal during asymptomatic periods, diagnosis is frequently delayed. We report a 63-year-old man whose recurrent muscle symptoms, creatine kinase elevation, and episodes of rhabdomyolysis had begun at approximately 49 years of age. Despite recurrent episodes and an initial diagnosis of myositis, the underlying metabolic disorder remained unrecognized for more than a decade. Comprehensive genetic testing identified a homozygous CPT2 c.338C > T (p.Ser113Leu) variant, classified as likely pathogenic by the reporting laboratory, which, together with the compatible clinical phenotype, strongly supported the diagnosis of CPT II deficiency. Following genetic evaluation, the patient received dietary counseling and was advised to avoid prolonged fasting, strenuous exercise, and other potential precipitating factors. During approximately eight months of follow-up, no recurrent rhabdomyolysis episodes occurred, creatine kinase levels remained within the normal range, and the patient remained asymptomatic. This case highlights the importance of considering CPT II deficiency in adults with recurrent unexplained rhabdomyolysis and emphasizes that delayed recognition may occur even when symptoms have been present for many years.