A French team has published their report on the cause of dyslexia.  Here is a typical report on what they have said.  You will see others in the press and around the web:

http://psychcentral.com/news/2011/12/22/dyslexia-tied-to-disrupted-processing-of-speech-sounds/32911.html

There are two vital things to know about it:

First, learning to read French is quite different to learning to read English.  English is much harder.  It is the inconsistency of English spelling that leads to most cases of dyslexia.  Therefore, while what they describe is a factor in some English-speaking dyslexia, it is relatively rare here.  Auditory processing difficulties are unusual.  In fact most dyslexics are very vocal.

Second, both in English-speaking countries and in France it is quite definitely NOT the ONLY cause of difficulty.  There are several others.  For the individual, it is their particular difficulty that is important.  Everything else is irrelevant to them.

The latter point is one of my great frustrations!  So often you see people talking about “the” cause of dyslexia.  That can lead to a lot of confusion and frustration for the people they are advising.  If you tell someone that the cause of their difficulty is one thing and it is actually another, you are clearly doing more harm than good.

It seems there is a tendency for researchers to find one link and immediately think the whole thing is solved.  I guess it is only natural, but if they dug a little deeper they would soon realise their mistake.