That's only because existing IQ tests aren't normalized past 160. IQ is defined by a statistical distribution, and that requires sampling the general population

That's only because existing IQ tests aren't normalized past 160. IQ is defined by a statistical distribution, and that requires sampling the general population. People with more than 160 IQ are so incredibly rare, there's no samples to define that end of the distribution. But that's irrelevant to this. Because we are dealing with the actual genes that determine intelligence, we can estimate the exact distribution of intelligence, and predict where a set of genes would fall on that distribution. See my comment below.