This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gluconeogenesis, Subject name: Biochemistry
Which of the following enzymes is coded by X-chromosome? 
Select and explain. 
A. alpha-L-Iduronidase, B. Iduronate sulfatase, C. b-Galactosidase, D. Hyaluronidase
B: Iduronate sulfatase
Answer: B: Iduronate sulfatase 
Explanation: option b - Iduronate sulfatase is coded by X-chromosome Mucopolysaccharidoses Rare inborn errors in the degradation of glycosaminoglycans; Characterized by mental retardation and/or skeletal abnormalities. Classified under lysosomal storage disorders. Hunter syndrome inherited - X-linked recessive mode deficiency of enzyme Iduronate sulfatase. All the other MPS are inherited in autosomal recessive mode.