The heart and kidneys were isolated at birth (3–6hrs), and since cardiac dysfunction, as measured by redox ratio, was apparent at this time point, and it coincides with neonatal deaths in the severe (HADHAe4−/−) group (lower RR levels), it strongly suggests that heart failure due to dysfunctional heart mitochondria is the reason for HADHA mutants neonatal death. Here, HADHA is linked to heart failure.