I think it happen’s anywhere.  It would depend on what you view is false information really.  It isn’t really clear in your post what your old Doctor has said that is wrong so it is hard to say whether he/she has done wrong. 

If it is something like a referral that totally misleads another Doctor to treat a child differentl;y then that WOULD be grounds for suing that Doctor.  However, if it is a straight forward open letter about growth and progress and monitorings then, it may merely be a case of he/she not informing you along the way about various things that cropped up because he/she thought you may not understand.  I.e. blood tests results being out, or growth not being the same as chronological age.  They also don’t really write very clearly sometimes and it seems to read as gobbledy gook to us but to them it is technical lingo. 

I have to admit it isn’t just with CAH I am having problems.  I saw a Doctor a week or so ago about my knee and immediately he examined it he said it was then medial lateral ligament either torn or lax and ordered an x-ray to check for fractures to rule that stuff out.  I returned for the x-ray the next day but the Doctor was not on duty so I saw another one.  He looked at the x-ray and then started going on about mensical tear and said he would refer me to a specialist.  When I went to see that specialist last week, I had only been referred as a meniscal tear and no one had told the specialist that I have a ligament torn which has caused the knee to be unstable and possibly the cause of any tear.  One problem that needs to be resolved and should have clearly been referred the the Specialist.  As a result he scripted a knee brace designed for those with menscal tears and it was the wrong one.  I only found this out when I went back to the Orthotics place this week to change it because it wasn’t supporting my knee enough.  The right brace (a hinged one with metal supports at each side) has now been sent for.  

These are simply communication errors and lapses between one Doctor and another basically.  However, when they occur it is very important to get them corrected if you feel that the contents are not correct because as you say they are on record and are what other Doctor’s use to script, treat and monitor as well as know the patient.  So anything not communicated or wrongly communicated does actually matter. 

Was the letter about her behaviour as a girl or about health issues that you wern’t aware of?