This is the third of three posts on how to answer the question ‘is it genetic?’ While the first post discussed spontaneous changes that just happen(genetic conditions), and the second discussed specific known hereditary genetic mutations, this third post digs into hereditary conditions, which are likely influenced by our genes, but either is the result of a variety of genes or whose genetic cause hasn’t yet been identified.
Examples of hereditary tendencies
Depression, substance abuse, height, and type 2 diabetes are all examples of hereditary conditions. These are things that you are more or less likely to have, but there isn’t any particular genetic marker showing that you will or won’t develop it.
In last week’s post, the conditions mentioned had very specific malfunctions that were the result of multiple copies of one or two specific genes being out of whack.
This week’s focus is on things that can’t be tested for, won’t show up on any modern genetic test, but still seem to occur more often in certain families than others.
This is the space where nature and nurture collide and generally, the possibility or threat of inheriting the condition is there but never guaranteed. There are usually no tests to predict whether or not your child might inherit these traits.
My experience with hereditary tendencies
There are a few things I have inherited or feared inheriting.
Depression is something that definitely runs in my family. My maternal grandmother had depressive tendencies, as did my mother, as do I. I inherited that potential, though I believe the triggers were different and just how it was expressed also varied.
In my case, my depression was triggered by a strong sense of loss and a fear of being left behind(which I associated with being abandoned feeling unworthy of love).
It reared its head when I was nine years old, after the deaths of my maternal grandmother, a close family friend, and my art teacher over the span of about three months. These deaths were predated by about three years by my great-aunt’s death in a car accident and my maternal grandfather’s death by stroke.
Since then, deaths and losses have been my primary triggers for depressive episodes.
Another tendency that runs in my family is one towards alcoholism or addictive tendencies.
My mom’s parents were both heavy smokers and drinkers, with high chemical dependency.
It looks like my mother and her siblings did not express that tendency, but my father also had problems with alcohol prior to my birth.
To my knowledge, he didn’t drink any alcohol my entire life.
I grew up fearful of alcoholism, and refused to participate in the typical teenage drinking behavior out of that fear.
I appear not to have inherited that tendency, but I still make the point of not developing regular alcohol habits to help protect myself from that risk. My sisters also appear not to have inherited these tendencies.
My primary disabling condition, Functional Neurological Disorder(FND) is suspected to also be a genetic tendency, but not a genetic condition.
It does seem to occur more often in families, with a percentage of parents and children sharing the diagnosis, or siblings or other close family members both being diagnosed with FND.
With FND one of the big challenges is the frequency with which the diagnosis is missed or people are misdiagnosed. There also hasn’t been enough follow-up with long-term histories of people with the condition to prove it yet.
nature vs. nurture: probably a bit of both
These tendencies are thought to have a genetic component because they do occur more frequently and similarly with people who are related to one another than the population in general.
However, families also tend to share other things, like socioeconomic status, traumas, dietary habits, and living environment. The implication of a genetic tendency is that even controlling for those things, the similarity in symptoms is still higher than one would expect.
The other side of it is that people who deal with the same or similar trauma or other factors are less or more likely to have the same response.
For example, I have FND. It’s often associated with trauma(physical or emotional, doesn’t matter). However, my life experiences were nowhere near as potentially damaging as other people’s experiences who didn’t develop FND. Why?
The guess is that this is because I carry a collection of genes that increases the likelihood of my brain processing trauma into FND symptoms instead of coping in a different way.
Some people’s coping mechanisms are likely to be more debilitating than my FND symptoms, while other people might have such healthy coping mechanisms that they don’t appear to be damaging. But everybody is different and each person’s body has a different go-to response, which is generally a mix of their genetic conditioning and their social upbringing and personal experience.
How likely is this to be inherited?
While the other two genetic conditions have definable percentages of risk(for example, when discussing Kleinfelter syndrome, one in every 500 boys born has an extra X chromosome, and in the case of cystic fibrosis two people who carry the mutation responsible for cystic fibrosis have a 25% chance of having a child with cystic fibrosis), this vague ‘it runs in families’ type of condition doesn’t have a percentage, because the genes involved haven’t been identified yet.
Again, in some cases, this may happen with further research, while in others, it’s likely to always be just a possibility.
There are a lot of conditions that have genetic components but aren’t predictably inheritable. The severity is also extremely variable, which is another factor.
For example, a person with a family history of developing type II diabetes can greatly minimize the risk of developing diabetes symptoms or type I diabetes through diet and exercise. In fact, in some cases, living that healthy lifestyle may mean that even though they carry that genetic tendency, they never actually have diabetes or symptoms of it.
My mother and grandmother’s history with depression doesn’t mean that either of my sisters has depression, though in my case I did go through multiple depressive episodes.
However, having gone through depression doesn’t mean that I’m forever in a state of depression – I both take anti-depressant medication and put a lot of effort into protecting my mental and physical health, both of which minimize my risk of falling into a severe depression.
In fact, I haven’t had a major depressive episode in close to 15 years, though I have occasionally gone through brief periods of depressed moods. My risk is higher than people without a family history or personal experiences with depression, but that doesn’t mean that I can’t live a good quality life anyway.
Everybody alive today has some form of genetic flaw, often several, and these flaws are a natural part of genetic inheritance and evolution.
The question with it all is whether or not these ‘flaws’ are manageable and how disruptive each is in terms of quality of life and personal opportunity.
To my mind, the big question is about the dignity of human nature and I personally am in favor of having this world be as diverse as possible – you never know what genetic mutation will end up becoming a key to the survival of our species, nor what insights or potential insights may be lost if an individual doesn’t exist due to their genetic flaws.
There also isn’t a ‘perfect’ model to work from. All of the calculations involved are of averages and likelihoods and probabilities.
The genetic conditions listed here aren’t easily identifiable yet, and the percentage chance of a particular embryo containing them is not calculable.
That there is a greater than zero chance of having any of these is reality, and while knowing that a parent, grandparent, aunt, uncle, or cousin had it means that it’s possible to occur in you, that’s simply part of how life works, and not something to end a possible life over.
Managing life with an inheritable condition
Just like hair or eye color is inheritable, and heights are affected by both genetic inheritance and dietary choices(healthier eating lets you fulfill your genetic potential, severe dietary restrictions may decrease growth opportunities), genetically who you are is based upon your parents’ genes.
There’s nothing to you whose potential didn’t exist in them, but you are a new mix of these genes and exactly how that will turn out is never predictable beyond probabilities.
It is our differences that make us unique, and the specific differences that we inherit are part of what makes us who we are.
Foreknowledge of the risks is often helpful because it can guide some of our priorities and choices. Also, choosing a healthier lifestyle, in general, can greatly assist us in living our best possible lives – knowing what the risks are can be helpful guidelines for what to focus on.
For example, I do have a fear of substance abuse, but I balance that carefully with my desire to enjoy a bit of alcohol on occasion.
I am careful to drink socially but not build habits around alcohol, and to think about whether I feel like having a drink or if I feel like I *need* a drink. I’m grateful that the second hasn’t occurred, but knowing my family history, I’m aware of that concern.
A friend of mine started to develop diabetes, due in part to a family history of obesity and that genetic tendency.
Once she was diagnosed, she did her research and implemented a severe diet change that utterly changed her body and life. She lost a lot of weight and kept it off, and at this point, her tests no longer suggest that she is pre-diabetic.
If she returned to her old diet, the symptoms would come back, but as long as she sticks with this lifestyle change, she is no longer in danger of diabetes or the symptoms that go with it.
My history of depression is again something I am managing. I’ve learned multiple positivity techniques that I actively use on a daily basis, and I do my best to keep my life stresses manageable – generally, I try to create long-term solutions to my problems and stresses so that while I might struggle for a little while, once I solve a problem, it stays solved.
I encourage you to look at whatever challenges you have inherited as puzzles to manage, so that you, too, can feel happier and more hopeful about your life.
I inherited endometriosis, adenomyosis from my mum and various other conditions from various family. Earlier I’d have moments of frustrated humour of how everyone has decided to gift me a problem but now I see the person I’ve become and I’m fine with what I go through.
I feel that doctors need to be more thorough in taking family history and we as patients need to be more thorough in understanding family history so that we can make our doctors more aware of this which then may help in earlier diagnosis rather than waiting years on end with no doctor believing you.
Shruti, I agree!
Most medical histories I have seen only focus on the absolutely deadly stuff. I have filled out lots of patient histories that ask what all your immediate family died from, but I am struggling to picture these questionnaires asking about what issues your family has lived with.
This can be key to improving our quality of life, but I just don’t remember that question being asked!
Being aware of genetic tendencies can help inform both our life decisions and our medical conversations. So glad you found this post useful!
I’m the same. Everyone in my family is autoimmune going back on both sides of the family, so I got all the genetic stuff. I’ve passed that info on to all my doctors because it should have a huge impact on my treatment.
It blows my minds that doctors don’t take that more seriously here in Taiwan. I know it would be taken very seriously in North America.
I do think it’s manageable in some respects. Lifestyle management is key, especially if you know what you might be pre-disposed to. My 80-year-old father is still so worried about heart disease because his father passed away at a young age. Throughout my childhood, he was constantly warning us about the dangers we had in our family and there was always a huge emphasis on eating right and getting lots of exercise and good sleep. (He’s a coach, so no surprise there.) In his case, he’s a great example of someone who took the information he had and made adjustments in his life to ensure he lived a long one. I’m really proud of what he has accomplished.
Glad to hear your father was that kind of proactive! Lifestyle changes can be effective than medications, and can prevent or minimize the need for medications.
Thank you for sharing, it’s really nice to hear about proactive folks taking steps to manage and minimize the severity of those potentially inherited traits!
I appreciate that you say, “Everybody alive today has some form of genetic flaw, often several, and these flaws are a natural part of genetic inheritance and evolution.” It was hard two summers ago when my son was diagnosed with bipolar type 2 because my mom had bipolar. So, I felt to blame. But, someone helped me to realize that all of us inherit crud from our ansestors. We also inherit many wonderful things. We can’t pick and chose (at least, I really wouldn’t want to if science gets to that point, too dystopian for me.)
On my maternal-side alcohol addiction is major. I had 3 uncles who were off the chart IQ intelligent who ended up as “functioning” alcoholics. My husband’s family has issues throughout with alcohol and other addiction. So, this was something we really talked a lot about with our children. I think that helped them not get too into the drinking in high school/college when their peers were.