Epigenetics is a specific group of mechanisms that control which genes 
get expressed. DNA methylation is only one epigenetic mechanism. There 
are many ways to disrupt development that are not epigenetic.

Folate deficiency reduces overall levels of DNA methylation more if 
someone is also methionine deficient. Methionine is a very strong methyl 
donor, and can help compensate for lower levels of folate or reduced 
MTHFR activity. Most good dietary sources of methionine are animal 
products. Do we see more errors of imprinting in vegans?

It's important to remember that in science, correlation does not imply 
causality.

If neural crest migration is a major mechanism in tt, one would likely 
see skin and hair pigmentation issues, eye malformations, and nervous 
system anomalies in individuals with tt from this mechanism. Do we?

Again, I find this area of investigation interesting, but don't think we 
have anywhere near enough information to form a theory yet (in the 
scientific sense of the term).  We're still at the hypothesis stage.

Catherine Watson Genna BS, IBCLC  NYC  www.cwgenna.com

On 8/26/2014 1:39 AM, Jennifer Tow, IBCLC wrote:
> Cathy,
>
> I didn't say all TTs are X-linked; my point was that they are not. A teratogenic environmental exposure would be an epigenetic event and again that was my point. I did not say that we KNOW that folic acid causes TT; I said that we know that the migration of neural crest cells is driven by methylation and given that folate is essential to methylation, it is a strong contender as a factor. New genes associated with TT that were previously unknown have been idenitified in the past two years specfically bc of interest in MTHFR and no doubt others will be found as well.
>
>
> Jennifer Tow, IBCLC, USA & France
> Intuitive Parenting Network, LLC
>
> Not all tongue-ties are X linked! Some are, but some may be autosomal
> dominant, it depends on the particular gene that causes them. We
> certainly don't know all the genes that contribute to tt, we have only a
> very few identified.
>
> The different gender distribution of anterior and posterior tt's does
> NOT imply an epigenetic cause for posterior ties. It just means the
> specific mechanism of inheritance is different (autosomal versus sex
> linked, for example). Or the cause may be non-genetic entirely, it could
> be developmental (from a teratogenic environmental exposure, for example).
>
> And we don't have a clear link between folate and tt yet. It's an
> interesting hypothesis, but with many
> missing links in the chain of
> theoretical plausibility. I too await further research in all these areas.
>
>
> Catherine Watson Genna BS, IBCLC  NYC  www.cwgenna.com
>
>
>   
>
>
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