This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: HMP Shunt Pathway, Fructose, Galactose Metabolism, Subject name: Biochemistry
Lactose intolerance is due to - 
Select and explain. 
A. Deficiency of Galactokinase, B. Deficiency of Uridyl transferase, C. Deficiency of Lactase, D. Deficiency of Enteropeptidase
C: Deficiency of Lactase
Answer: C: Deficiency of Lactase 
Explanation: Ans. is 'c' i.e.. Deficiency of Lactase Lactose intoleranceo It occurs due to deficiency of lactase, the most important member of b-galactosidase enzymatic class.o Lactase hydrolyses lactose into glucose and galactose in the small intestine.o Lactose is present in milk.o Therefore, deficiency oflactase, (b-galaetosidase) results in intolerance to milk and other dairy products.o Clinical features are bloating, diarrhea, failure to thrive, abdominal distension and abdominal cramp.