I have also heard of medical examples like that. However, this article argues that generalizations based on apparent racial characteristics are medically unreliable.

https://www.scientificamerican.com/article/race-is-a-social-...

> Yudell said that modern genetics research is operating in a paradox, which is that race is understood to be a useful tool to elucidate human genetic diversity, but on the other hand, race is also understood to be a poorly defined marker of that diversity and an imprecise proxy for the relationship between ancestry and genetics.

> ...

> "What the study of complete genomes from different parts of the world has shown is that even between Africa and Europe, for example, there is not a single absolute genetic difference, meaning no single variant where all Africans have one variant and all Europeans another one, even when recent migration is disregarded," Pääbo told Live Science. "It is all a question of differences in how frequent different variants are on different continents and in different regions."

> In one example that demonstrated genetic differences were not fixed along racial lines, the full genomes of James Watson and Craig Venter, two famous American scientists of European ancestry, were compared to that of a Korean scientist, Seong-Jin Kim. It turned out that Watson (who, ironically, became ostracized in the scientific community after making racist remarks) and Venter shared fewer variations in their genetic sequences than they each shared with Kim.

> ...

> "If you make clinical predictions based on somebody's race, you're going to be wrong a good chunk of the time," Yudell told Live Science. In the paper, he and his colleagues used the example of cystic fibrosis, which is underdiagnosed in people of African ancestry because it is thought of as a "white" disease.

Humans are not "basically the same" but humans are also not easily divided into a couple of genetically separate races. Many black Americans, for example, have white ancestors. And black Africans are genetically far more diverse than the entire rest of mankind put together. There are people with every possible skin colour between black and white. Our insistence on drawing a handful of arbitrary lines between them is cultural, and not based on a clear genetic separation.

That said, skin colour does have some physiological impact: darker skin blocks the impact of the sun on our skin, which is great for preventing sunburn (and skin cancer, I think?), but reduces the amount of vitamin D our skin creates, and vitamin D deficiency can have an impact on all sorts of things (no idea if glaucoma is one of them). That makes it a trait, though, not a race.