Polymerase Gamma Mitochondrial DNA Depletion Syndrome Initially Presenting as Disproportionate Respiratory Distress in a Moderately Premature Neonate: A Case Report

A 32-week premature infant presented with respiratory failure, later progressing to pulmonary hypertension (PH), liver failure, lactic acidosis, and encephalopathy. Using exome sequencing, this patient was diagnosed with a rare Polymerase Gamma (POLG)-related mitochondrial DNA (mtDNA) depletion syndrome. This case demonstrates that expanding the differential to uncommon diagnoses is important for complex infants, even in premature neonates whose condition may be explained partially by their gestational age (GA). It also shows that patients with complex neonatal diseases with significant family history may benefit from exome sequencing for diagnosis.

A Variant in SLC25A4 Leads to Mitochondrial DNA-Depletion Syndrome-12A Causing Neonatal Hypotonia and Hypoventilation

Congenital hypotonia and hypoventilation is a rare association. We report a rare case of a female newborn with poor respiratory drive, ventilator dependency, severe hypotonia, cardiomyopathy, and premature death. Clinical-exome-sequencing revealed SLC25A4-related mitochondrial deoxyribonucleic acid (DNA) depletion syndrome-12A (cardiomyopathic type). This syndrome is apparent at birth and carries a poor prognosis.