For starters a gene might not directly cause a disease. Then we should know more about the gene before trying to modify it. For instance autism is likely to have genetic factors that increase the chance of having it but twin studies clearly indicate that it is not 100% genetic, meaning the gene itself is not responsible. In that case it may be better to test for the gene and then prepare the environment accordingly to prevent the development of autism rather than changing the gene. The right environment (and perhaps nutrition) would likely result in a very intelligent, analytical, but socially competent person and it's the wrong environment that screws this up.
Secondly, there are many different opinions on what it means to live a good life or the best way to go about thinking and acting in the world. So we should be careful that we are not just imposing the mainstream view of how a person should think.
There are cases where this is the obvious choice, such as curing Huntington's Disease.
Yes, medical science should genetically modify the human brain to treat disease. Any time you mention something involving genetics in modern society, people get all spooky about it. Usually that's out of ignorance. Genetic manipulation in humans is something that we should embrace, especially when it comes to making us healthier.
I personally think that medicine should genetically modify the human brain to treat diseases because it would not be as many diseases going around. I personally think that medicine genetically modify the human brain to treat diseases because so people would not have to go through a lot of tests.
Yes, we should have medicine genetically modify the human brain to treat disease. This will be the only 100% sure fire way to cure some diseases and while there may some issues when it first happens, it will evolve just like the rest of medicine and become a common practice.
I believe if pharma can produce medicines that modify the human brain to treat diseases then we should absolutely look into the viability of that option. It sounds like an idea that will need a lot of study before being released to the public, but if something fights diseases without unwanted reactions then we should use it.
If there is a way to genetically modify the human brain to treat diseases, it should be all means happen. However we can stop people from suffering so badly, we should act on. This will probably be possible in the near future, and we should jump at the opportunity once it does arise.