SCR6 and Episodic Ataxia

[paul456]

Bit confused not sure if sca 6 can cause EA or you can have them both?

Quote from Professor Wood from my recent update:

Patients can have episodic ataxia on the background of progressive ataxia.

Thought these were two completely different types of ataxia.

Just when I was thinking I new all about ataxia 😊

[Jenandbeth]

I can't comment on your individual case but I can say that as a child Beth was initially diagnosed with episodic ataxia. As an adult she was diagnosed with SCA 19/22 and the degeneration is fairly consistent ... that said there can be 'episodes' where it seems worse but it's a bit catch 22. Does she fall because of an episode when her balance and coordination are worse and it all passes in time? OR Does she fall then lose her confidence which makes her balance and coordination worse for a period before her confidence is regained!?! Answers on a postcard! I think I'm thinking there probably can be episodic on top of underlying slow degeneration but this is purely anecdotal I'm not a neurologist!

[paul456 in reply to Jenandbeth]

All straight forward stuff this disorder 🤪Hope you are both as well as you can be.

Thank you 😊

[wobblybee]

In a nutshell..yes there is a link

Point mutations of the CACNA1A gene coding for the α1A voltage-dependent calcium channel subunit are responsible for familial hemiplegic migraine (FHM) and episodic ataxia type 2 (EA2). In addition, expansions of the CAG repeat motif at the 3′ end of the gene, smaller than those responsible for dynamic mutation disorders, were found in patients with a progressive spinocere-bellar ataxia, named SCA6. In the present work, the analysis of two new families with small CAG expansions of the CACNA1A gene is presented. In one family, with a clinical diagnosis of EA2, a CAG23 repeat allele segregated in patients showing different interictal symptoms, ranging from nystagmus only to severe progressive cerebellar ataxia. No additional mutations in coding and intron-exon junction sequences in disequilibrium with the CAG expansion were found. In the second family, initially classified as autosomal dominant cerebellar ataxia of unknown type, an inter-generational allele size change showed that a CAG20 allele was associated with an EA2 phenotype and a CAG25 allele with progressive cerebellar ataxia. These results show that EA2 and SCA6 are the same disorder with a high pheno-typic variability, at least partly related to the number of repeats, and suggest that the small expansions may not be as stable as previously reported. A refinement of the coding and intron-exon junction sequences of the CACNA1A gene is also provided.

Copied from researchgate.net 1391

[paul456 in reply to wobblybee]

Thanks W Bee Not sure the people that write these things understand them 🥴

At least I now know.

Thank you 👍🏻

[wobblybee in reply to paul456]

🙂 It’s tempting to research, but obviously it’s not always easy to understand medical jargon, and it can be all to easy to misinterpret..But in this case we can see the answer is yes..