This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inhalational Anesthetic Agents, Subject name: Anaesthesia
Gene for the ryanodine receptor, mutation in which is responsible for malignant hypehermia is located on which chromosome- 
Select and explain. 
A. Chromosome 19, B. Chromosome 17, C. Chromosome 18, D. Chromosome 16
A: Chromosome 19
Answer: A: Chromosome 19 
Explanation: Malignant hypehermia is a genetic(autosomal dominant) hypermetabolic muscle disease. Malignant hypehermia is a genetic disorder; there is a defect in the gene that codes for the protein ryanodine receptor (RyR) in skeletal muscle. Ryanodine receptor is a Ca2+-release channel present in the membrane of L-tubule of skeletal muscle. When it couples with dihydropyridine receptor (DHPR)from T Tubules , there is release of Ca2+ into the sarcoplasm, initiating muscle contraction.So Increased Ca++ transpo L-type calcium channels in T-tubules leads to malignant hypehermia DHPR is an L-type voltage-sensitive Ca2+ channel. Rarely inhalational anaesthetics can cause A malignant hypehermia manifesting as muscle rigidity, sweating and masseteric spasm