SURF1 and Leigh syndrome: For example, short stature was far more prevalent (95%) in patients with Leigh syndrome (subacute necrotizing encephalomyelopathy) with complex IV assembly defect caused by surfeit locus protein 1 (SURF1) deficiency (88), compared to 52% in complex IV deficiency caused by variants in LRPPRC which encodes a protein that plays a role in mitochondrial RNA metabolism (85).