A Rare Presentation of Carnitine Palmitoyltransferase II (CPT-2) Deficiency With Normal Acylcarnitine Profile in a 10-Year-Old Boy With Muscle Weakness and Bilateral Hearing Loss

Carnitine palmitoyltransferase II (CPT-2) deficiency is a rare and autosomal recessive disorder of long-chains fatty acids oxidation. Here, we report a 10-year-old boy with a bilateral hearing loss and a myopathic form of CPT II deficiency which was confirmed under molecular genetic test analysis. He was admitted to our hospital with unexplained headache, vomiting, and fever. Furthermore, he developed seizures, muscle weakness, neck stiffness and pain, mild respiratory distress, and icteric appearance. The laboratory test results also showed sever elevated levels of lactate dehydrogenase (LDH) and Creatine phosphokinase (CPK). He had also icteric appearance with unexplained hyperbilirubinemia. Further examinations revealed normal heart, liver without neurological disorders. Muscle pathological examination reported normal pathology without neuromuscular and mitochondrial disorders and storage diseases. Finally, molecular test analysis with next generation sequencing (NGS) revealed a homozygous pathogenic variant in the CPT-II gene, c.338C>T p. (Ser113Leu) which was correlated to CPT-II deficiency fatty acid oxidation disorder. Furthermore, we identified a homozygous pathogenic variant in the ADGRV1 gene, c.15736C>T p.(Arg5246*), which suggest the Usher syndrome type 2C and the reason for sensorineural hearing loss in this case. Our finding indicates that CPT-II can be associated with multiple symptoms and clinical features. Therefore, evaluation of CPT-II deficiency with molecular test analysis may be helpful in cases with unexplained icteric appearance, muscle weakness and rhabdomyolysis.