Can insurance companies in the U.S. still reject or charge more for new customers based on the patients' prior conditions?

That was one of the major reasons to keep patient genomic data offline.

Edit: Nevermind, looks like it's not a problem anymore (http://www.genome.gov/24519851)

Nope, still a problem. GINA only applies to health insurance and employment.

http://www.genome.gov/10002077#al-2

"Where GINA Does Not Apply

GINA does not apply to employers with fewer than 15 employees. GINA's protections in employment do not extend to the US military. Nor does it apply to health insurance through the TRICARE military health system, the Indian Health Service, the Veterans Health Administration, or the Federal Employees Health Benefits Program. Lastly, the law does not cover long term care insurance, life insurance or disability insurance."

While a few states have laws restricting the use of genetic information in the underwriting of these forms of insurance, nothing addresses the use of this information for other forms of discrimination. (Think credit redlining.)

Unfortunately, participating in any form of genetic testing is still a terrible idea for Americans, as it can have real financial consequences. Data are forever. Once this material is "out there," the law only provides recourse in a few specific circumstances (and you have to have the resources to enforce these rights through the legal system.)

The only way to win is not to play.

There is way way more hype than reality on MTHFR . Placebo remains the most effective drug we have.

The effects of supplements (primarily methylfolate and methylcobalamin) seems to depend on which mutation C677T, A1298, or both, and whether the person is homozygous or heterozygous.

However, the biggest difference is having an answer, instead of doctors guessing and prescribing thyroxine or antidepressants (which can make life so much worse).