Consumer DNA testing - how do they communicate non-XX, non-XY status?

Factual Questions
1

Those home DNA tests sold for genealogical research – how do they handle communicating to people the fact that their chromosomes are neither XX nor XY, in the cases where that’s so? I think it’s about 1% of people who fall outside the two most common sex chromosomal makeup, the great majority of them unaware. Perhaps consumer DNA tests don’t actually detect this? I’ve never heard of anybody learning this through their test. There must be many thousands of customers for whom this would be the case.

2

23andMe covers this issue in an FAQ page:

So it seems that most of the non-standard sets of chromosomes (46 plus XX or 46 plus XY) would not show up in their test, as they’re not looking at the sex chromosomes.

3

So it does indeed.

Hey, thank you for tracking that down for me! That’s very kind of you. I genuinely appreciate it!

4

Their tests could pick up the presence of two X chromosomes where only one is expected, if the subject happens to be heterozygous (two variants present) at one or more of the loci they test on X. So this could pick up undiagnosed Klinefelter, since the XXY phenotype is male.

What they do with this information if it comes up - I have no idea.

5

For an analogy, these tests just do a key-word search on your DNA, they don’t read the whole text.

6

And now I’m thinking of this XKCD comic:

7

Is that really true about spellcheck? And how do you add a spelling to spellcheck as incorrect? I thought it simply underlined anything that was NOT in its list of spellings.

This is one of those times I suspect myself of cluelessness but really can’t tell.

8

The “Explain XKCD” website on 2298: Coronavirus Genome

9

It’ true that spellcheck just looks at a list of known strings and flags as red anything unknown.

But if you add the current genetic sequence of letters to spellcheck as a known correct “word” and later find a sequence that’s almost the same, it’ll be flagged as unknown to spellcheck and therefore you know it’s different from all your known sequences already saved as correct words.

10

Is what true about spellcheck? That you can add custom words to it? Yes, of course. Do biologists use Word to analyze DNA sequences or use spell check to identify mutations? No, absolutely not, that is the joke.

11

That’s what I was asking about being true. It wasn’t clear to me that that was a joke. Thank you!