Bi-allelic variants in BOLA3 cause MMDS type 2 with hyperglycinaemia (MMDS2; MIM#614299), typically characterized by infantile encephalopathy, leukodystrophy, lactic acidosis, non-ketotic hyperglycinemia and death in early childhood [5,7,11]. The gene discussed is BOLA3; the disease is Infantile encephalopathy.