Two weeks ago, I talked about the different kinds of allergies, how they work, and their conflict potential. Genetic diseases are another area that doesn't often make an appearance, except for maybe the occasional high-profile condition, but there are far more types of genetic conditions than autism and Down's syndrome.
(Alert to the queasy: biology talk ahead.)
There's a condition that means you have to stay healthy and avoid infections, else risk gangrene and amputation (diabetes). There's a condition that mean a bunch of benign tumors grow throughout your body, which can destroy tissue and turn malignant at any time (neurofibromatoses, NF). There's a condition that means you have to carefully watch your diet or else you'll end up with brain damage (phenylketonuria, PCU).
I haven't even scratched the surface.
You might know I'm a proofreader. What you might not know is that proofreaders also tend to be good at genetics, and vice versa. My original career plan was to become a research geneticist as a day job, while I wrote fantasy on the side.
See, I have a genetic disorder.
Oh, I look normal. Put me beside just about anybody, compare how much I eat to what I weigh, and I'll seem enviably healthy. Okay, so I have to watch the ingredients in what I eat, and I sometimes wear sunglasses inside to nip a migraine in the bud, but no biggie. Lots of women have allergy and migraine problems.
You know your endocrine system? The one that makes and regulates the hormones, that keep the rest of your body in order?
My endocrine system can't even manage itself.
The condition I have is misnamed, presumed rare, and often described incorrectly. It's either insulin resistance that causes the endocrine problems, or endocrine problems that cause the insulin resistance. Doctors keep changing their minds. (Insulin resistance is what causes adult-onset diabetes. That means anyone with my condition is probably prediabetic, too.)
What I have is PCOS, PolyCystic Ovarian Syndrome. And according to a study done more than 5 years ago, 5-10% of women have it, and it's genetic. Guys can have it, too (though the study didn't specify what guys' symptoms were.) And doctors still call it rare.
The problem stems from genetic expressivity and penetrance. You can have the genes for something that doesn't actually show up. You might have the gene that says "Add another finger and/or toe", but it won't necessarily penetrate. So you won't have that extra toe that your uncle had.
Once a condition does penetrate, it may not be 100% expressive, meaning it might show up to different degrees. If you cross a pea plant with red flowers with a pea plant with white flowers, you'll get a pea plant with a specific shade of pink flowers. But if that flower color gene were less than 100% expressive, you might end up with different shades of pink.
PCOS (and many other conditions) are not 100% expressive, and they possibly might not completely penetrate, either. That's why diagnosis and treatment are such a nightmare.
So now doctors say women can have the cysts on the ovaries without having PCOS, and completely ignore the variety of symptoms that can stem from having a messed-up endocrine system. I was diagnosed by doctors researching my condition. Since then, I've had more than one endocrinologist be skeptical—even though I have symptoms like metabolism trouble. My metabolism's just hyperactive; usually the metabolism is hypoactive.
In other words, most women with PCOS have very slow metabolisms. That's why they struggle to lose weight. My metabolism's overactive; I have to fight to maintain my weight. Imagine having to eat even when you're not hungry—and having to buy enough food to feed someone 2-3 times your weight. It gets expensive.
Endocrinologists are skeptical and won't admit I have it, these days, because I never had my testosterone levels checked—even though I have particular symptoms of elevated testosterone levels. (You know those big hairy women who were shown off in freak circuses, once upon a time? High testosterone. Fortunately, most of us with the condition aren't that furry.)
I also started getting hot flashes when I was 20 years old. That isn't a typo. A few years ago, at the end of a hot flash, I lost my cold sensation. I can detect cold, I get goosebumps and shivers from getting too cold, but I don't feel cold, myself.
Imagine discovering you're cold because you realize your feet are numb and your toenails are turning blue. It's kind of scary.
The loss of cold sensation may not be related to the PCOS, though I think it is. The hot flashes? Definitely related. (If you get hot flashes, try putting an ice brick on the back of your neck the next time one flares. If one isn't available, sticking your head in the freezer also helps, but it probably isn't very good for you.)
I'm not saying all this to complain. I'm used to my body, so it doesn't seem so bad to me as it does to someone else. I'd rather have my condition than NF. My friend with NF would rather have her condition than mine.
I'm saying all this to point out that genetic conditions, like allergies, have variety and implications that can make your story all the richer.
Does your teen girl with PCU drink the diet soda because she thinks it'll help her lose weight, even though she knows the aspartame is poisoning her neural system? Does your character with NF envy her healthy sisters and daughter because the tumors have misshaped her face, making her feel ugly?
What's your favorite example of a character with a genetic condition? Have you written any characters with genetic conditions?
Personally, I like Graysha Brady-Phillips in Shivering World by Kathy Tyers. Graysha's genetic disease is slowly killing her, it limits what she can do, and it affects the entire story—but only because it's an integral part of who she is.