10 year-old with muscle weakness and pain our son (shawn) had a probe placed into his thigh several weeks ago and the doctor confirmed myopathy. Since that test, shawn has had a muscle biopsy procedure at the hospital (thigh). The results showed no signs

Your . Your son probably does have a myopathy. The problem with a muscle biopsy is that the piece of tissue taken out is very small and may miss affected muscle. Your doctor has probably done a CPK test. This is a blood test that measures an enzyme released when muscle is damaged. There are also special stains that are used to look for different causes of myopathy on biopsy material. There is a dry blood spot test that looks for acid maltase deficiency that can present with muscle weakness and pain. The testing is paid for by the company that makes an enzyme replacement therapy for it. I hope this gets sorted out for you soon.
If . If there continues to be uncertainty regarding his diagnosis, your doctor may consider a referral to dr. Erika finager, a pediatric neurologist specializing in neuromuscular issues at ohsu, in portland, oregon. I believe she is the only pediatric neuromuscular doc in the state of oregon.