A novel mutation leading to the lethal form of carnitine palmitoyltransferase type-2 deficiency

Sudden Death of a Four-Day-Old Newborn Due to Mitochondrial Trifunctional Protein/Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiencies and a Systematic Literature Review of Early Deaths of Neonates with Fatty Acid Oxidation Disorders

Mitochondrial trifunctional protein (MTP) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiencies have been a part of the Slovenian newborn screening (NBS) program since 2018. We describe a case of early lethal presentation of MTPD/LCHADD in a term newborn. The girl was born after an uneventful pregnancy and delivery, and she was discharged home at the age of 3 days, appearing well. At the age of 4 days, she was found without signs of life. Resuscitation was not successful. The NBS test performed using tandem mass spectrometry (MS/MS) showed a positive screen for MTPD/LCHADD. Genetic analysis performed on a dried blood spot (DBS) sample identified two heterozygous variants in the HADHA gene: a nucleotide duplication introducing a premature termination codon (p.Arg205Ter) and a nucleotide substitution (p.Glu510Gln). Post-mortem studies showed massive macro-vesicular fat accumulation in the liver and, to a smaller extent, in the heart, consistent with MTPD/LCHADD. A neonatal acute cardiac presentation resulting in demise was suspected. We conducted a systematic literature review of early neonatal deaths within 14 days postpartum attributed to confirmed fatty acid oxidation disorders (FAODs), which are estimated to account for 5% of sudden infant deaths. We discuss the pitfalls of the NBS for MTPD/LCHADD.

Diagnostic Challenges in the Myopathic Variant of Carnitine Palmitoyltransferase II Deficiency: A Case Report

Carnitine palmitoyltransferase II deficiency is a rare metabolic disorder affecting the mitochondrial oxidation of fatty acids. We present a case of the myopathic form in a 10-year-old Bahraini male following an initial presentation of exercise-induced rhabdomyolysis and transaminitis. There was no consanguinity or findings suggestive of an underlying inborn metabolic disorder. Tandem mass spectrometry on dried blood spots showed no abnormal acyl-carnitines profile. The condition improved with hyperhydration, high glucose intake, carnitine, and alkalinization. Genetic testing revealed a compound heterozygous pathogenic variant c.338C>T (p.Ser113Leu) and a variant of unknown significance c.729_731del (p.Leu244del). The patient was kept on a high carbohydrate and low-fat diet with medium chain triglycerides supplementation and advised to avoid long fasting periods and strenuous exercise. Within the four years of follow-up, he had three further attacks. Exercise-induced myalgia or rhabdomyolysis should raise the suspicion of inherited metabolic disorders. Metabolic investigations should be taken during the acute illness, and an acylcarnitines profile should preferably be performed in the serum.