This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics, Subject name: Pathology
Protein affected in spinocerebellar ataxia type 6 
Select and explain. 
A. Ataxin, B. a1A-Voltage-dependent calcium channel subunit, C. Atrophin, D. Androgen receptor
B: a1A-Voltage-dependent calcium channel subunit
Answer: B: a1A-Voltage-dependent calcium channel subunit 
Explanation: Ans. (b) a1A-Voltage-dependent calcium channel subunit(Ref: 19tha/pg 451)Spinocerebellar ataxia type 6 is due to CACNA2A gene on chromosome 19pl3.3, which codes for a1A-Voltage- dependent calcium channel subunit protein.