Has anyone got any experience as to whether LDs (or certain of them) are passed on via genetics? Annecdotally, I notice statistics saying that ADD kids tend to be boys by a wide margin and was wondering if they were perhaps sex-linked. Also, I have seen other studies saying that ADHD problems are more common in poor socioeconomic groups, so perhaps there is linking to nuture as well as nature. [But I’ve worked at a private LD school, so there is certainly a showing of ADD and ADHD and LDs of various sorts among even very rich people.]
I have done genetics counseling and it got me to wondering if this is perhaps something (like heart disease, diabetes) that wouldn’t be a good idea to try to track through a family’s generations.
Re: Genetics, yes and no, nurture yes (in a roundabout way)
We live in a time when genetics appear to be king. Science is so hot to completely map the human genome, that we have a focus on this that enters into the realm of perseverance.
Fragile X, Rhett’s, Tourette’s, Asperger’s, and many other very specific forms of DD’s or LD’s have been determined to be passed along thru genetics. Other’s like CP are the product of some for of trauma to the fetus, whether in utero, like exposure to toxins, or during birth, like having the babies head squeezed a little too hard with the forceps used to facillitate delivery.
The jury is out on the big three, ADD/ADHD (upwards of 4-6% of live births), Dyslexia (upwards of 2-4% of live births) and autism (about 1 in 150 live births). While there is some strong evidence that supports a genetic link in these conditions, it is eluding the researchers at this point, and there are just as strong case pointing to other sources (ie., exposire to toxic mercury while the brain is still developing).
I have not done much research on ADD or Dyslexia; my son is autistic, and so most of my focus has been there. I do not presume to speak about ADD or Dyslexia, but do feel somewhat comfortable discussing autism. Please remember I am neither a doctor nor a research scientist, just a parent who has been engaged in serious amature research via the web for the last 3 years.
Autism is also predominantly a male problem, affecting 5 boys for every girl. This has caused many to look for this on the male chromosone, but they have not had any luck there at all. It can be explained however, if we look at the way males and females differ in the use of their brain. When males talk, they only use one hemisphere to do so, while girls use both. So if the autism is arisen from damage to this reagion of the brain, boys will develope very strong problems in communicating, while the girls ahve the right hemisphere to fall back upon. It is interesting to note that mercury seems to attack this area of the brain (one of the chief side effects of mercury poisoning is the loss of speech). Also, both pertussis and measles attack this region of the brain as well. The very reason we vaccinate against both pertussis and measles is to avoid MR and loss of communication. Pertussis does remain a very dangerous vaccine to use (the whole cell vaccine contains all the same toxins that the native or wild pertussis does), and the measles isa lvie virus vaccine, so the potential is there for both jabs to induce what they are meant to protect against. (The main reason Japan no longer uses the DPT or the MMR, among other countries).
There is a great possibility that their is a genetic component to autism that does not directly induce the condition. Many autisic people have been shown to have a genetic defect that causes them to not have a specific protein which assists the body in the elimination of toxic metals. So they ahve a genetic problem which may be triggered when the child is exposed to mercury in thimerasol for instance. So there is a genetic component, but it would not be a problem if the child did not get the exposure to ethyl mercury.
One the other hand, nurture has been demonstrated to NOT play a part in the formation of a condition like autism (or presumedly ADD and dyslexia). However, I think few would argue that poor parenting (especially in the extremes) would tend to allow a “naturally” occuring problem like autism to remain unremediated. So the autism was not caused by nurture, but certainly it was compounded by the lack of nurture.
This will help explain why these problems may seem to be more pronounced in the poor, who very often lack the skills and certainly lack the werewithal to get the quality assistance their children need (too often the only source of assistance the poor can get for their children is that which is given thru the public schools, ie. damn near nothing).
The rich are often able to purchase very expensive private therapies, and so we may not see their children in the public schools, and therefore they remain uncounted. In truth, the “big 3” occur in almost identical prevalence across all races, nationalities or class lines.
Re: Genetics
I don’t think that the reality that learning differences tend to run in families is a secret. I don’t think we’re breaking new ground on this. Learning differences run in families and that reality is well-established and well-described.
there is a lot of literature that says that genetics plays a signficant role for some folks