Wow, it seems like I've come to the right spot. Thanks Jan for your expertise. It's amazing that you know more about this than my doctor. Your help is much appreciated!

I found that study indicating that particular SCN4A mutation is likely benign, but then I found some newer studies indicating it may not be:
http://www.ncbi.nlm.nih.gov/pubmed/18046642
http://europepmc.org/abstract/MED/15583983

Regarding congenital myasthenic syndrome, it fits in a way because it can cause for example double vision but i have severe vision problems beyond just double vision, neuropathies, and so on, really more resembling MS on paper than anything else (from testing I have ruled out MS).

But even myasthenic syndrome is a fatigueable weakness, and that isn't too apparent with me. I suppose it is in my eyes, but when I have bouts of weakness they are totally intractible and unresponsive to anything. Those bouts of weakness sometimes make it hard to shave, eat, etc. And a couple of times I got to the point where I couldn't move my arms or legs at all, but that is rare.

I read Joe's post as well indicating it is possible it is causing sensory neuropathies but there just isn't enough research on it yet. That would be sad if that's the case because I'm so sick of fighting an uphill battle having to deal with something that no one knows about and to convince my doctors how disabled I am from my symptoms.

So my hunch is that it is a major causal factor if not the major causal factor in my symptoms. Part of that is because I have so exhaustively ruled out other pathologies that it makes this a lot more likely.

But the question is how to prove that it is, and then deciding whether it is an ayptical manifestation of mc, pmc, or congenital myasthenic syndrome, or if it is a different clinical entity that hasn't been researched enough yet.

Thanks for your informative response, and I will try to get in touch with you as well Joe!

Type of Myotonia: Ayptical myotonia or paramyotonia

Hi, lou
I am also disabled by way of an SCN4a "benign" snp. I was forced to diagnose myself after Neurologists accused me of lying about my symptoms.
I got the requisition from Athena Diagnostics over the internet and filled it out myself. My GP who openly professed no knowledge of neurology signed it (I am sure just to humor me).

There are ancillary conditions that are associated with some sodium channel gene defects. The severity of the ancillary condition is NOT related to the severity myotonic muscle disease.

There are so few people affected that it is suggested (with a question mark)that sensory neuropathy is connected to some sodium channel defects.
A long standing sensory neuropathy often affects the eyes.

Email Jan and have her give you my email address. I can share many documents that my research has found, and give you some suggestions on testing.
Thanks, Joe

Type of Myotonia: SCN4a

Country: US

Hi, lou
I checked the LOVD (Leiden Open Variation Database).
The SCN4a (xxDNA change)p.Val781Ile defect has been reported once
as producing hypokalemic periodic paralysis.

The database lists a number of DNA changes that produce the same amino acid change.
Thanks, Joe

chromium.liacs.nl/LOVD2/variants.php?select_db=SCN4A&action=view_all&order=Variant%2FDNA%2CASC&hide_col=&show_col=&limit=250

That string deliberately does not produce a link but if you copy it into your address bar with or without "http://" as appropriate it should take you to
the right place.

Type of Myotonia: SCN4a

Country: US