This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Beaded ribs with epiphysial swelling is a feature of: 
Select and explain. 
A. Vit D deficiency, B. Vit A deficiency, C. Vit C deficiency, D. Vit K deficency
A: Vit D deficiency
Answer: A: Vit D deficiency 
Explanation: Rickets is characterized by the continued formation of the collagen matrix of bone, but incomplete mineralization results in soft, pliable bones. 
In osteomalacia, demineralization of pre-existing bones increases their susceptibility to fracture. Insufficient exposure to daylight and/or deficiencies in vitamin D consumption occur predominantly in infants and the elderly. 
Vitamin D deficiency is more common in the northern latitudes, because less vitamin D synthesis occurs in the skin as a result of reduced exposure to ultraviolet light. 
Loss-of-function mutations in the vitamin D receptor result in hereditary vitamin D-deficient rickets.
Vitamin D deficient rickets leads to epiphyseal swelling with beaded ribs known as Rachitic rosary.

Key Concept:
Vitamin D deficient rickets leads to epiphyseal swelling with beaded ribs known as Rachitic rosary.
Ref: Lippincott’s illustrated reviews for biochemistry, 7th edition.