<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes X-linked dominant scapuloperoneal myopathy ? [/INST] What causes X-linked dominant scapuloperoneal myopathy? X-linked dominant scapuloperoneal myopathy is caused by mutations in the FHL1 gene. The FHL1 gene is located on chromosome Xq26. This gene may be involved in muscle development or hypertrophy. </s>