Calico Cats and Kleinfelters

From Genome News Network.

As for the male calico in question, Gould had to look to the X chromosome, where the cat's gene for coat color resides. A cat, she tells us, can have either the "O" gene, for orange, or the "o" gene for black (or, strictly speaking, non-orange). Orange in this case is only partially dominant over non-orange, and a hybrid, "Oo," has a coat with a little bit of orange, a little black—in other words, calico. And since the color gene is on the X chromosome, you can't have a male hybrid, any more than you can have a male carrier of sex-linked diseases like hemophilia, because males have only a single X.

Except, that is, for cats like George. George, it turns out, has the feline version of Klinefelter syndrome, a genetic anomaly that strikes an estimated one in 500 baby boys and is caused by trisomy of the sex chromosomes, leading to the genotype XXY. Although the Y chromosome makes George male, that extra X gives him as many loci as a female would have for the coat color gene. This means he can indeed be a color hybrid, with "O" on one of his X chromosomes and "o" on the other. To someone in the know—as readers of this book are by now—George's calico coat announces his hybrid status, and his hybrid status announces that he must have at least one more X than does a typical male.

One less obvious fact about George, however, is that he isn't a straight XXY. His true karyotype is XXY/XY, which makes him a genetic mosaic. Klinefelter himself documented dozens of such mosaics, in whom not every cell contained exactly the same arrangement of chromosomes. Among them were such bizarre combinations as XXY/XXXY, XXXY/XXXXY, XX/XXXY/XXY, and X0/XY/XXY. In George's case, only half his cells are the standard Klinefelter XXY. The other half, it turns out, are just ordinary male XY.

"So George isn't a new and wonderful type," his indulgent owner concludes. "He's just another boring old XY/XXY, five of which have already been reported in the literature."

I'm not Kleinfelter - though that was considered a distinct possibility at one stage, specifically a X0/XY/XXY mosaic - but I hang around with some who are. Most are guys with a minor anomaly. A few are girls with a somewhat greater anomaly. Usually. The medical literature records a few who have given birth.

One of the girls, Ms Y, is currently in Montreal, Quebec, getting her last somatic ambiguity resolved. Her surgery is scheduled for Tuesday. I wish her and her partner (the fabulous Ms X) all the very best.

I've only met them twice, once at Chonburi, where some corrective surgery was performed on Ms Y when I was getting my surgical revision done. And once on the way back from Montreal in late February. But I've known them for years over the Internet.

I won't mention their names, nor even their initials. You see, when their situation was made known in the place they used to live, the locals disapproved. Having narrowly escaped an attempted firebombing of their house, they moved elsewhere, and are now "stealth", just a normal, average, lesbian couple. It's safer that way.

Many of the GLB set where they live now wouldn't approve, you see.

For that matter, what can the labels "heterosexual" or "homosexual" mean when someone is 47xxy? Neither 46xx (genetically female) nor 46xy (genetically male)? But anyone who's ever met Ms Y could have no doubt of her gender. She's stunning, and Ms X gives her competition there too. They are, in every sense of the word, beautiful women. Just two of the outstanding people on this planet who I never would have met had it not been for my metabolic whoopsie.

It was a Gift, and not just because of the relief that things finally felt right.