Neonatal severe cardiopulmonary failure due to mitochondrial methylation defect

A rare mitochondrial disease characterized by a variable clinical phenotype ranging from fetal hydrops and postnatal hypotonia, bradycardia, and respiratory failure, resulting in death in the neonatal period, to infantile onset of episodes of acute cardiopulmonary failure associated with severe lactic acidosis, and slowly progressive muscle weakness. Muscle biopsy shows reduced activity of mitochondrial complexes I, III, and IV.