Task: Question Answering
Input (English): Context: Christianson syndrome (CS) is an X-linked neurodevelopmental disorder caused by deleterious mutations in SLC9A6. Affected families organized the inaugural Christianson Syndrome Association conference to advance CS knowledge and develop questions that may be prioritized in future research. 
 Question: Mutation of which gene is implicated in the Christianson syndrome?
Output (English): slc9a6