Hypochondroplasia -epilepsy

OK, as promised, I will start adding bits and pieces for the medical section of this blog as part of my new year's resolution.

Please remember that all of this is my opinion and I am not medically trained.

I would welcome all comments and guest posts, so we can gather and share what we know. 

To start off, let me just say that hypochondroplasia and related seizures is a really interesting and very under-researched subject... Apart from a few studies, not much seems to have been done to explore this area.

Apart from a few experts no one really seems to make the connection, I have personally spoken to 2 parents whose kids have had seizures and were told that it wasn't related.

Even if you read the official gene mutation review: http://www.ncbi.nlm.nih.gov/books/NBK1477/, epilepsy is not mentioned. 


I think one of the reasons why the connection is often not made, is that hypochondroplasia is quite rare; the best estimates say it impacts 1:350,000 live births (so 3-4 in 1 million). But  it is also not typically diagnosed until toddler age and in some cases a lot later. At the same time the vast majority of seizure symptoms seem to occur in the first year of life. So by the time HCH is diagnosed, the epilepsy is either under control with medication or even gone. So no wonder, the connection is not made.


If you do a search on google which I am sure you would have all done, if you are reading this,
you will find that the same few cases are cited over and over again, most often the one about one family where 2 of the children had medial temporal lobe dysgenesis and seizures: http://www.ashg.org/genetics/ashg07s/f20570.htm

Temporal lobe dysgenesis seems to feature in all cases that I could find. The reasoning says that because the FGFR3 also expresses in the brain, it could be causing this structural abnormality.

In terms of frequency I have seen 5-10% and 10% quoted by different authors.

Children with hypochondroplasia also have macrocephaly (and I will write about this soon) so that could also increase the risk of developing neurological symptoms, including seizures.

All kids whose parents I have spoken to had the the infancy onset seizure-precipitated apnea that appears to be the most common one based on Dr. Pauli's study as well. 



Here is the google docs link to the wonderful Dr. Pauli's study summary:

https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B23x_OlN3FTNNzA1MDVmZGMtOTUxNS00OWEyLWFiNGEtNjMxYmM2YjllMGQ2&hl=en_US

So what should you do if you worry that your child has seizures, do exactly what you would do with any other child, except when you meet with the doctors, you may want to print out the study and take it with you.

If your child has apneic episodes or seizure-like events, they should have an EEG and and MRI of the brain, but I think this is standard practice anyhow. 

Should you do anything if your child doesn't have seizures? Our pediatrician was really pushing for an MRI and I refused, I didn't want to have Fi sedated and examined for something that she just has a higher risk for.