Do renal and cardiac malformations in the fetus signal carnitine palmitoyltransferase II deficiency? A rare lethal fatty acid oxidation defect.

The neonatal form of carnitine palmitoyltransferase II (CPT II) deficiency is a rare lethal inherited disorder of fatty acid oxidation. Carnitine essentially transfers long-chain fatty acids across the mitochondrial membranes for β-oxidation, where CPT II plays a key role. CPT II deficiency phenotypical forms include lethal neonatal, severe infantile and myopathic forms. We present a term small-for-gestational-age neonate with hypoglycaemia, seizures, refractory cardiac arrhythmias and intracranial haemorrhage. Plasma acylcarnitine profile and the genetic study confirmed CPT II deficiency. Additionally, likely pathogenic variants in the SLC22A5 gene point to primary carnitine deficiency. Antenatal findings of polycystic kidney disease and cardiomegaly were confirmed postnatally. All supportive measures, including extracorporeal life support, failed to improve the clinical course, and the baby succumbed. Major renal, cerebral and cardiac anomalies were reported with CPT II deficiency. In our case, fetal polycystic nephromegaly and cardiomegaly with parental consanguinity should have signalled the possibility of this disorder.