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A case report
Introduction: Fatty acid metabolism disorders are a group of rare and hereditary diseases, which arise when the enzymes involved in it do not work correctly. Among these disorders are enzymatic defects in the mitochondrial carnitine transport pathway or beta-oxidation. In this case report we will focus on beta-oxidation, mainly on acyl-CoA deficiency very long-chain dehydrogenase. Very long- chain acetyl-CoA dehydrogenase is a coenzyme that catalyzes the first step of Beta-oxidation of fatty acids long-chain. Deficiency of this coenzyme is associated with 3 phenotypes. The first being severe with early onset presentation involving multi-organ failure occurring in early infancy. The second type which occurs in early childhood and presents with hepatomegaly and hypoglycemia, without cardiomyopathy. And the third being a delayed onset type which presents with myopathy and intermittent rhabdomyolysis, an autosomal recessive disorder with an incidence of 1:30000 to 1:100000 at the global level.
Goals: To review a rare case of a fatty acid disorder in order to make clinicians aware of this condition and educate them on recognition of this entity.
Case Presentation: An 18-year-old male with history of rhabdomyolysis in 2020 requiring emergency hemodialysis is recently diagnosed with Hypertension managed with Enalapril. Patient denied consumption of any toxic substances. His family history includes Rheumatoid arthritis in his mother and maternal aunt; and End stage kidney disease in his maternal grandfather. The patient has two healthy sisters and a brother without any prior history of rhabdomyolysis. He presented with a one day history of asthenia, vomiting, myalgia, and dark urine which began spontaneously. He denied any preceding fever, urinary symptoms or ingestion of toxins/ alcohol. On physical examination he was found to be febrile, with oliguria, pitting edema in lower limbs diminished motor strength 2/4 and difficulty walking due to leg weakness, with preserved strength and tone in upper extremities. Laboratory evaluation revealed a CK 112,698 IU/L, BUN 0.84 gr/L, Serum Creatinine 26.2 mg/L , blood glucose 1.39 g/L, Lactate 2.6 mmol/L, Potassium 5.4 mmol/L, Hct 39%, Hb 13.3 mg/dL, WBC 10700/mm3, Platelets 225000/mm3. Given these findings emergency hemodialysis was started and a work up for causes of rhabdomyolysis was pursued. He was found to have a weak positive FAN, electrophoresis showed hypogammaglobulinemia, RF 19 U/ml, C3 C4 CH50 normal, panel of antiJo1 negative myosites. Serum TSH and Free T4 were within normal limits. HIV and Hepatitis Serologies were Non-reactive. Abdominal ultrasound showed a liver with signs of grade II steatosis and both kidneys with signs of nephropathy. For a presumptive diagnosis of metabolic myopathy with rhabdomyolysis, subsequent studies were undertaken. Quantitative acylcarnitine test in blood spots in filter paper showed a moderate increase in long-chain acylcarnitines (C14, C14:1, C14:2) and the C14:1/C14 ratio; slight increase in C16:2 and C12 and free carnitine descent. Due to these findings, a genetic analysis by a next generation sequencing was requested. This analysis detected compound heterozygosity in the ACADVL gene that are associated with “very-long chain acyl-CoA dehydrogenase deficiency”.
Discussion: Very-long chain acyl-CoA dehydrogenase deficiency is a cause of rhabdomyolysis with very low prevalence. Our case report aims to educate readers about this rare clinical entity so that they may consider it in their differential diagnosis of rhabdomyolysis and provide timely care and treatment.