<prompt> HDN is seen due to deficiency of vitaminACKE  <response>: Vit k is necessary for coagulation. Factors dependent on Vit k are synthesised on the liver as inactive zymogen. They undergo gamma carboxylation, which requires Vit k as a cofactor. Clinical Manifestations of Deficiency i. Hemorrhagic disease of the newborn is attributed to vitamin K deficiency. The newborns, especially premature infants have relative vitamin K deficiency. This is due to lack of hepatic stores, limited oral intake breast milk has very low levels, 15 mglitre and absence of intestinal bacterial flora. ii. It is often advised that pre-term infants be given prophylactic doses of vitamin K 1 mg Menadione iii. In children and adults, Vitamin K deficiency may be manifested as bruising tendency, ecchymotic patches, mucous membrane haemorrhage, post-traumatic bleeding Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 462 