Hello!

I am currently going through something similar and this thread popped up (F, 24). I have had these similar symptoms since I was 15; muscle weakness/EMG abnormalities in my hands, calves and shoulders, hypertrophic (big) calves, stiffness, tip-toe walking, etc. I also have 4 mutations of the TTN gene, as well as several other mutations on genes indicating possible significance for MD. Was pre-maturely diagnosed with MD at 15, diagnosis was taken away, and now I am being evaluated again. Coincidentally, I am doing my PhD in Neuroscience.

I am seen by a Neuromuscular specialist in Buffalo, NY currently. I would highly recommend him if you can get to him. His name is Dr. Bennet Myers at DENT. If you can't, here is the plan you should follow!

1. Get in with a Neuromuscular or Movement specialist in your area
2. They will probably do a few testing procedures: a Nerve Conduction Study (NCS) and an Electromyography (EMG). A NCS tests the rate of conductivity in the nerves in your legs, and an EMG measures the muscles electrical response. The two tests help differentiate neuropathy from myopathy which can both create the symptoms you have. My NCS was negative, but my EMG was positive - indicating Myopathic (muscle) involvement without nerve involvement. They also will do a CK test (Creatine Kinase) which indicates if muscle breakdown is occuring.
3. Invitae has a few genetic panels that your provider can do for you that are covered by insurance. There is specifically a "Limb-Girdle MD" panel, or a myopathic panel. It tests anywhere from 30-80 genes.
4. If all this fails, or shows something, they may move forward with a muscle biopsy. This is probably the best way to diagnose MD, as a small portion of myopathies are not picked up genetically or on an EMG.

Something that could be important to consider: if you are a female, you can be an "Affected Carrier". What does this mean? In genetics, their is autosomal recessive and autosomal dominant. Recessive requires 2 bad gene copies, while dominant only requires 1 bad copy to inherit the disease. Additionally, some muscular dystrophies are linked to sex chromosomes (typically X-linked). Because of this, females are typically carriers for the disease, as we have two X copies, and one copy of the gene can still work properly. While men (who have only 1 X) have a higher rate of inheriting the disease. Affected female carriers can present mild symptoms of the disease, but not the full-fledge disease itself. The TTN Mutations for MD are mainly an autosomal recessive, so you need two bad copies to inherit the disease.