NNT and hyperinsulinemic hypoglycemia, familial, 4: In fact, C57BL/6J (6J) mice, which exhibit a genetic mutation leading to mitochondrial nicotinamide nucleotide transhydrogenase (NNT) deficiency [51] and thus generate fewer mitoROS under pressure overload, were protected from RHF compared to NNT-competent C57BL/6N (6N) mice [6].