Genetics and schizophrenia, pregnancy risks
December 9, 2012 12:51 PM   Subscribe

Genetics and schizophrenia, what are the risks in having children?

It's come up now and again in comments on other questions, but I wonder if there's any particular insight or expertise specifically on the subject.

Asking because there's a couple thinking about getting pregnant. Both are in good mental health but her mother is very seriously schizophrenic. This might-become-mom herself -- separated from her schizophrenic mother early on -- has been spared that. She's early-mid 30s now, past the age at which it typically has onset.

There may not be a bottom line on this, but I wonder if there's any sense of where the science stands. I'm clear there's a greater risk that her children would inherit the likelihood of schizophrenia. Is there a sense of the likelihood?
posted by cloudscratcher to Health & Fitness (12 answers total) 2 users marked this as a favorite
I would suggest an appointment with a genetic counsellor would be the most fruitful source of current information as well as a possible source of entry into any research studies that are currently being conducted and may provide various types of testing for free.

It is good to be informed, but recognise too that we are not yet at the point of knowing which fetus' will develop which diseases. There is, for now, an element of risk (and luck) in any pregnancy.
posted by saucysault at 12:57 PM on December 9, 2012 [7 favorites]

If you go for genetic counseling, please be aware that there is a strong likelihood that the genetic counselor works for the genetic testing company. Even if you book it via your ob/gyn or physician.

We went for genetic counseling for a particular issue in our family. While we got the answer we needed re: the question we were asking, we also got a lot of other, horrifying facts and figures, and didn't realize until afterwards that the "counselor" was actually a salesperson doing her best to steer us toward an array of costly tests. The counseling was conducted at the same facility where we had our amnio, and we had assumed that we were getting impartial medical facts akin to what we got via the amnio. We weren't.

So, perhaps as a first step, discuss this question with your physician, gyno, and or OB/gyn.
posted by BlahLaLa at 1:11 PM on December 9, 2012 [5 favorites]

Best answer: Any person has a 1 in 100 chance of having schizophrenia. If one parent has the disorder the child has a 13 in 100 chance of developing it. So a grandparent being affected would have a lower risk than 13 in 100. Anecdotal: aunt has schizophrenia, none of her 12 siblings have it, nor do any of her 30 nieces and nephews or her son.
posted by Sal and Richard at 1:27 PM on December 9, 2012 [1 favorite]

Best answer: Research has shown that there is both a strong genetic and environmental component to schizophrenia. The problem is the the genetic component hasn't yet been identified, so there's no test like there is with Tay-Sachs or other, more gentically simple congenital disorders. There are endophenotypes related to schizophrenia that are seen in non-affected first-degree relatives (olfactory disturbances, for example) but I don't think that will tell you anything about the risk of a child developing the disease.

So my sense is that she is at elevated risk of having a child with schizophrenia (calling someone "schizophrenic" or "a schizophrenic" is a no-no in some circles, FWIW), but it's almost impossible to say how elevated that risk is beyond just counting affected relatives.

If she chooses to accept this elevated risk and have a child, she should just be aware of the risk, the environmental contributing factors (stress, upheaval), and early intervention and warning signs for the disease. (This is something a lab I used to work in did research on-- linking early endophenotype presentation to eventually developing the disease.)
posted by supercres at 1:38 PM on December 9, 2012 [6 favorites]

This is an area of active research and funding, by the way. Mostly because many people want to be able to answer exactly this question. You may be able to find more info about ongoing research here (disclosure: my former lab).
posted by supercres at 1:41 PM on December 9, 2012

The risk for developing schizophrenia is around 10% if a first-degree relative has the illness and 3% if a second-degree relative has the illness. That's compared to a 0.6-1.9% risk in the general population.

So if the hypothetical child's grandmother has schizophrenia, the risk to the child is slightly higher than normal, but still fairly low.
posted by dephlogisticated at 2:33 PM on December 9, 2012

Response by poster: supercres, Sal and Richard, thanks, that's helpful (and appreciate learning the sensitivity to terms)

Sal and Richard, is that 13 in 100 from somewhere in particular? It does feel absurd seeking to quantify the risk, but these are the times we live in, perhaps, maybe.

A wildly naive question, this, but for someone who has been diagnosed with schizophrenia, is it half the risk for the grandchild, as opposed to the child?
posted by cloudscratcher at 2:42 PM on December 9, 2012

A first-degree relative is a parent, child, or sibling, whereas a second-degree relative is a grandparent, grandchild, aunt, uncle, nephew, etc.

So if a person has been diagnosed with schizophrenia, the risk of their child developing the disease is 10%, and the risk of their grandchild developing it is 3%.
posted by dephlogisticated at 2:50 PM on December 9, 2012

Here's one link
posted by Sal and Richard at 2:53 PM on December 9, 2012

There is a difference between familial and sporadic. Is her mother the only member of the extended family to show symptoms? I'm the mother of a young man who suffer from Schizophrenia with late onset ( in his late twenties): his disease is apparently the result of a traumatic head injury, since there is no history of mental illness in the extended families of both sides and there is evidence of a connection between brain insult and Schizophrenia.

Since I belong to NAMI I have come in contact with several families that show high expressivity of the disease but all of these families have many members who are disease free. A genetic counselor is my recommendation too: your best bet in finding one is a medical school associated with a pediatric hospital or a cancer center.
posted by francesca too at 3:45 PM on December 9, 2012

I forgot to include this chart of relative risks.
posted by francesca too at 3:48 PM on December 9, 2012

francesca too's chart illustrates this, but because this is not a case of classic Mendelian inheritance (i.e. it's not just a dominant or recessive genetic trait - the genetic factors at play have not been identified and there are environmental factors as well), this is why the risk for grandchildren cannot be calculated in some straightforward way by knowing the risk for children.
posted by treehorn+bunny at 11:58 PM on December 9, 2012

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