Background. Carnitine-acylcarnitine translocase deficiency (CACTD) is a rare, autosomal recessive, and highly lethal fatty acid oxidation (FAO) disorder caused by defective acylcarnitine transport across the mitochondrial membrane. CACTD is characterized by severe episodes of hypoglycemia and hyperammonemia, seizures, cardiomyopathy, liver dysfunction, severe neurological damage, and muscle weakness. Herein, we described the clinical features, biochemical, and molecular findings of three patients with CACTD, presented with poor feeding, hypoglycemia, liver dysfunctions, and hyperammonemia, but died despite intensive treatment. Cases. All cases had similar signs and symptoms like poor feeding and respiratory failure associated with liver dysfunction. Urinary organic acid profiles in the presence of hypoglycemia and hyperammonemia led us to the possible diagnosis of one of fatty acid β-oxidation defects. Results of the molecular analyses were compatible with CACTD. In addition to known mutation (c.270delC;p.Phe91Leufs*38) we detected a novel one (c.408C > A;p.Cys136*). Conclusions. All three cases died despite a very intensive therapy. Based on our experience with these three cases, it can be said that CACTD has a relatively poor prognosis, molecular studies are of most importance in suspected cases for the final diagnosis and such studies might be of help while giving genetic counselling and guidance to parents for future pregnancies.

Objectives: Propionic acidemia (PA) is an autosomal recessive multisystem disorder caused by the deficiency of propionyl-CoA carboxylase, encoded by PCCA and PCCB genes. This retrospective study presents the clinical and laboratory characteristics of PA patients followed up in our center. Methods: Included in the study were 50 patients diagnosed in a single center with propionic acidemia between 1984 and 2020, whose electronic and written hospital records regarding demographic, clinical, and laboratory features, along with diagnostic and therapeutic approaches, were reviewed retrospectively. Results: This cohort had a median age at diagnosis of 18 days and 91.1 % (n=41) were born at term. Consanguinity was notably prevalent (91.1 %), and a family history of PA was reported in 14 % of cases. No significant relationships were observed between clinical and laboratory parameters and mortality. Laboratory findings at the time of diagnosis revealed significant metabolic abnormalities, including low levels of free carnitine, elevated C3 propionyl carnitine, and varied amino acid imbalances. Twenty-three patients exhibited developmental delay and/or intellectual disability. Brain magnetic resonance imaging unveiled white matter involvement and ventricular dilatation in 9/25 patients. Furthermore, dilated cardiomyopathy (26 %) was noted in patients who had cardiac assessments. Among the study cohort, 27 patients survived, 23 patients died during follow-up. No significant relationships were observed between clinical and laboratory parameters and mortality. Conclusions: Despite improvements in the understanding of the pathophysiology and advances in diagnostic and treatment approaches, propionic acidemia and its long-term complications can still lead to severe consequences. This comprehensive evaluation offers valuable insights into the multifaceted nature of PA.