Case of Infant With Metabolic Crisis From Lactational Hypoglycin A and Fatty Acid Defect

Hypoglycin A is a mitochondrial toxin found in unripe soapberry fruits such as ackee. This toxin disrupts fatty acid β-oxidation, leading to severe metabolic derangements. Although toxic exposure through ingestion has been well documented, transfer through human milk is not well characterized. We report a full-term, exclusively breastfed 5-month-old infant, a carrier of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, who developed profound hypoketotic hypoglycemia, metabolic and respiratory acidosis, and vasoactive-refractory shock 2  days after maternal ingestion of unripe ackee fruit. Despite aggressive management, including fluids, dextrose infusion, levocarnitine, and empirical antibiotics, the infant developed ventricular dysrhythmias and cardiac arrest. He required venoarterial extracorporeal membrane oxygenation (VA-ECMO) for circulatory support. Metabolic evaluation showed impaired β-oxidation on acylcarnitine profile. Hypoglycin A was detected in breast milk, with concentrations decreasing over time following maternal ingestion. Genetic testing confirmed MCAD carrier status with 2 maternally inherited ACADM variants in cis. The patient was decannulated from VA-ECMO on hospital day 4 and discharged with normal neurological function. This case illustrates a "2-hit" model of toxicity, in which genetic vulnerability to impaired fatty acid oxidation compounded the effects of a mitochondrial toxin. It represents a rare and clinically significant instance of hypoglycin A toxicity transmitted via human breast milk and includes the use of extracorporeal life support for hypoglycin A-related metabolic collapse in a human. Clinicians must maintain a high index of suspicion for hypoglycin A exposure in critically ill, breastfed infants and proactively counsel lactating individuals to avoid consumption of unripe ackee fruit to prevent potentially fatal outcomes.