ABSTRACT
Methodical evaluation of a neonate with common clinical findings (hypotonia and lethargy) is important whenever it cannot be attributed to the frequent causes. This case report is on a preterm neonate with persistent hypotonia and metabolic acidosis who was evaluated and diagnosed with mitochondrial trifunctional protein deficiency. A preterm male baby, second born to second degree consanguineous parents, was found to have persistent lethargy and hypotonia with severe metabolic acidosis despite the shock being corrected. Strong clinical suspicion for inborn errors of metabolism (IEM) was considered despite negative reports of first tier investigations for IEM. He was started on carnitine and biotin. Whole exome sequencing of the baby and Sanger sequencing of mother revealed mutation in HADHA gene suggesting mitochondrial trifunctional protein (MTFP) deficiency. He was started on special infant formula containing medium chain triglycerides along with breastfeeding. When common causes cannot be attributed to the clinical picture, evaluation for uncommon aetiologies should be strongly considered. In case of IEMs, early diagnosis and appropriate therapeutic measures can have satisfactory growth and development in the child