CSNB & Nystagmus

[Nellie]

Hi Everyone

I posted some time ago about nystagmus being present in our family. After much research by our genetics team, they have found a significant mutation on a gene that confirms CSNB. I was hoping someone might be able to tell me if nystagmus can be a stand alone condition, even when the diagnosis is CSNB.

I have shown NOT to have the gene mutation but I still wonder if I might carry the x linked gene mutation thats causing nystagmus or if it's just a symptom of the CSNB.

Hope this makes sense.

Nel

[John Sanders]

Hi Nel,

Thanks for your post about CSNB (congenital stationary night blindness) and nystagmus.

As I'm sure you know, Nystagmus occurs with lots of other conditions, mostly to do with vision, but not always. Some examples are albinism, congenital cataracts and cone/rod dystrophies.

Nystagmus can and does occur with no known cause in some cases -- I'm one example. However, it's worth emphasising that word "known". There must be a cause for every case of nystagmus, it's just that we can't always work it out -- yet.

Doctors and vision scientists have become much better at finding the underlying causes of nystagmus in recent years. The more experienced ones can now diagnose the cause in around 80 per cent of cases. But there's still a lot of work to do in unravelling the links and the whole question of cause and effect.

You would have to talk to genetic counsellors - which if I understand correctly you are doing already -- to establish whether or not you might be a carrier.

John

[John Sanders]

Hi Nel,

Thanks for your post about CSNB (congenital stationary night blindness) and nystagmus.

As I'm sure you know, Nystagmus occurs with lots of other conditions, mostly to do with vision, but not always. Some examples are albinism, congenital cataracts and cone/rod dystrophies.

Nystagmus can and does occur with no known cause in some cases -- I'm one example. However, it's worth emphasising that word "known". There must be a cause for every case of nystagmus, it's just that we can't always work it out -- yet.

Doctors and vision scientists have become much better at finding the underlying causes of nystagmus in recent years. The more experienced ones can now diagnose the cause in around 80 per cent of cases. But there's still a lot of work to do in unravelling the links and the whole question of cause and effect.

You would have to talk to genetic counsellors - which if I understand correctly you are doing already -- to establish whether or not you might be a carrier.

John

[Nellie]

Thanks John. Theyve confirmed I'm nit a carrier of the csnb but could I still carry a gene fault for nystagmus separately. Or would you assume that the nystagmus is caused by the csnb?

Thanks again!

Nel

[John Sanders]

Hi Nel,

I have learnt that it's never a good idea to assume anything!

We don't fully understand the genetics behind nystagmus. Researchers currently believe that in a minority of cases genes (for example FRMD7) may directly cause nystagmus. In most cases. it's more likely that a gene causes something else -- like CSNB -- which in turn probably triggers nystagmus. But there's a lot to discover yet.

So, I would say the answer to your question is yes, you could possibly be a carrier of another gene which could lead to nystagmus. But again I would advise you to talk to experts in genetics for their view.

John