This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics And Genetic Disorders, Subject name: Pediatrics
Alpha1 antitrypsin gene is on which chromosome? 
Select and explain. 
A. Chr 11, B. Chr12, C. Chr 13, D. Chr 14
D: Chr 14
Answer: D: Chr 14 
Explanation: d. Chr 14(Ref: Nelson 20/e p 1941, 2053)a1-Antitrypsin deficiencyIt is caused by mutation in SERPINA1 gene (chr 14q), which has autosomal recessive inheritance.a1-Antitrypsin, a protease inhibitor synthesized by liver, protects lung tissue from destruction by neutrophil elastase;Most common allele of protease inhibitor (Pi) system is M & the normal phenotype is PiMM.