Gene detection means squat when it comes to intelligence or the positive impact it can have. Intelligence, even in a given area, means nothing without the ability to make use of it in a meaningful way.
My family would likely be ones that have the intelligence gene (there's no way to say that without it sounding like bragging/ego, it's really not meant that way). I believe that based on a number of factors, including the level of participation of extended family members in their respective fields, psycho-educational testing where scores are in the 90th+ percentiles, etc. What that intelligence gene wouldn't show is the impact it can have. Combined with the intelligence in my family comes issues with depression, ADHD, bipolar disorder, failure to recognize/interpret social indicators (partly related to ADHD), isolationist tendencies, etc. Those might be local to our genetics, however, the "absent minded professor", "genius idiot", "troubled genius", etc. stereotype exists for a reason.
For every major success in my family there's a major failure to launch, meaning they have a really hard time getting careers/life going despite what testing suggests. In my family I am one of the latter group. My Wechsler Adult Intelligence Scale tests (professionally administered) showed exceptional PRI scores like 98th percentile matrix reasoning & 97th percentile visual working memory and some truly horrible WMI/PSI scores as low as the 9th percentile. For me this has resulted in problems in school, friction in social arenas, bankruptcy, and currently: driving a forklift for a living. I have diagnosed & fixed a code efficiency problem in code that had been under constant optimizations for over 3 years, in a language I've never used, without seeing more than an outline of the original code, in less than an hour. Unfortunately that ability means nothing when working memory doesn't allow me to keep method names/etc in my head. It's akin to having the latest greatest processor with a tiny amount of RAM - the OS takes up most of the RAM and everything that's left is dedicated to the problem at hand - every time something else needs that space something important gets pushed out. Sometimes that's remembering to sleep/eat, others it's any concept of time, and mostly it's the "unimportant" details like method names/attributes/outputs (information that I can look up any time and isn't essential to the abstract core of a thing).
Point is, just because you can identify a gene and manipulate it to get better scores on testing doesn't mean it's going to result in something "better".