That's very interesting about the muscle biopsy. Do you think there's any way you can get the original results? I can't believe the doctor would disregard the biopsy!
There was a paper several years ago about a correlation between McArdle's and myotonia congenita. We have deteriorating or absent Type IIB fibers in our muscles, and those are the fibers that contain high amounts of myophosphorylase which is deficient in McArdle's. So perhaps that is the connection.
Since you already have an autoimmune condition, I would definitely get checked for celiac if you haven't already. They can start with blood tests, but an intestinal biopsy is the standard. Isaac's Syndrome is also an autoimmune disorder caused by antibodies to potassium ion channels and can cause some of the symptoms you mentioned. I have seen many autoimmune disorders, even serious ones like lupus, disappear with a gluten-free diet. But you have to do it 100%, not even a crumb with gluten grains on your food. It's being diagnosed so frequently now in the US that we have whole sections in the grocery stores devoted to gluten-free foods.
I have tried to get the results of the biopsy but that was 36 yrs ago. I even tried my childhood Dr to no avail. Some symptoms are similar to both McArdles & Myotonia Congenita.
Last year I had a biopsy for celiac, came back negative but as GP said I was following GF diet.I have been going to a dietician to sort out health issues so presently it feels like there is very little I can eat as I need to be dairy free also.
We have so many great resources now for gluten-free/dairy-free products and recipes in the US. Many parents of autistic children find it really helps, so the demand for good recipes really increased. Here are a few links for you:
MC is a condition that affects the skeletal muscles. The chloride channels which allow the exchange of chloride and sodium are altered by one or two mutations and this delays relaxation after a muscle is contracted. If you haven't read the MDA Quest article, it has a very good explanation:
Although some women only have noticeable symptoms when they are pregnant, most of us begin to experience the stiffness when we are young - some as toddlers, others around puberty.
The muscles affected include arms, legs, hands, feet, abdominals, diaphragm, throat and upper part of esophagus, face, eyelids, ocular (behind the eyes), scalp and tongue. The stiffness disappears as you warm up the muscle, but sets in again after a period of rest, even just minutes of being inactive. Some people have pain and cramping because of damaged muscle cells related to the myotonia, others have no pain and only experience the stiffness.
With the recessive form it seems to be more likely that you can freeze up suddenly which is very dangerous if you trip or are startled. If you fall you can't catch yourself.
MC does not affect smooth muscle as a rule (although some sphincter muscles may morph over time to include some skeletal muscle). So that means your gastrointestinal tract is not affected, and theoretically neither is your heart, although many of us do have palpitations or arrythmias that seem to be correlated with the stiffness.