Relative Genetic and Environmental Influences Differ by Location

A fascinating new study [press release here, full text freely available here] out of the Institute of Psychiatry at King's College London shows that the relative contributions of genetic and environmental influences on various cognitive and behavioral traits differ by location. In other words, if you live in location A, trait X might mostly depend on your genetic makeup, whereas if you live in location B, trait X might be more susceptible to variation in your environment regardless of your genes. Pretty neat stuff!

The authors assessed 6,579 pairs of 12-year-old twins in the UK on 45 different characteristics. Monozygotic ("identical") twins share all of their genes and dizygotic ("fraternal") twins share, on average, half of their segregating genes. There are components of the environment that are shared by both twins and components that are unique to each twin. By using these different correlations, we are able to determine how strongly each part of the equation affects a given trait by seeing how much more similar monozygotic twins are on that trait than dizygotic twins. 

Although most researchers know better, we tend to talk about these estimates of genetic and environmental influence as if they are static and fixed. This study serves as a great reminder that this is not the case. A trait can appear more genetic or more environmental depending on the genetic makeup of the sample used or the environment the sample lives in. 

The authors focused on just one of the 45 traits that they collected for this paper: a composite of teacher-rated classroom behavior problems. I've copied a portion of their figure below. It shows the strength of the influence of the non-shared environment on classroom behavior problems. The warmer (pinker) colors represent a stronger environmental effect and the cooler (bluer) colors represent a weaker environmental effect. As you can see, there is a trend toward Londoners' classroom behavior problems being more affected by the environment than those in outlying areas. 

Figure 3a. Unique environmental influences on teacher-rated classroom behavior problems

So what is it about London that makes the environment more potent for this particular trait? The authors posited it could be income variability. In other words, London has more people who are very rich and more who are very poor, while the rest of the UK is more evenly distributed. An environment that is more variable and extreme can have more of an effect than an environment that doesn't change much from person to person. When they plotted income variability, the resulting map looks very similar to the one above. This correlation doesn't prove that income inequality itself causes classroom behavior problems. It just provides a hint about what other mediating variables to look into more closely in the future.

You can download the files and scripts to explore the rest of the rich dataset yourself here. It's free, very quick and easy, and there's even a video to show you how to manipulate the program. I played around with it a little bit tonight to check out some of the autism data. The results of my brief exploration are below.

They administered the Child Asperger Syndrome Test to the twins' parents and teachers. In addition to an overall total, the measure has subscales for social, nonsocial, and communication. There are maps for the genetic component, common environment, unique environment, and overall variation. All of that means that there are 32 maps for autism alone! That's a lot to digest. I quickly realized that I could easily get sucked down a long rabbit hole of analysis and interpretation, so I had to limit myself (for now, at least). I looked at the parent-reported social subscale and overall autism score for each component. You can see my great image manipulation skills below.

My quick maps for some of the ASD data

Both the social subscale and the overall autism score seem to follow a similar pattern to the classroom behavior problems reported in the paper: the nonshared environment is more influential in London and genetics is more influential in outlying areas. The difference is certainly more subtle for the social subscale, though. 

We already know that income variability is one factor that could potentially mediate this relationship. In general, it seems that the relative contributions of genetic and environmental influences on the development of autism differ by something that differentiates the UK's urban and rural areas. This is an exciting avenue for future research.

In addition to the important findings and implications of the data themselves, the authors are hopeful that this paper will help propel an already-developing "trend towards integrating visualization into the analytic process, instead of approaching it as a way to effectively communicate the outcome of a completed study." In other words, we scientists should take advantage of our ability to spot patterns by making various sorts of images of our data for our own exploratory purposes. Don't wait to make a pretty graphic until it's time to publish! 

In order for this to happen, we need to forge collaborations with people who specialize in this sort of thing. I'm not an expert in generating effective visualizations and I'm never going to be the best one to write the code for it, so apparently I need to start making some new friends... [edit: ew I accidentally used the wrong too before :( ]

O S P Davis, C M A Haworth, C M Lewis, & R Plomin (2012). Visual analysis of geocoded twin data puts nature and nurture on the map Molecular Psychiatry DOI: 10.1038/mp.2012.68

Reflections on IMFAR 2012

Last week I traveled to Toronto for the International Meeting for Autism Research (IMFAR). I had an awesome time. There was so much I wanted to share that I just had to start a blog about it. So here goes! I start with more personal commentary, move into things about conferences and science in general, then finish with some of the specific scientific results I learned while there.

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The night I got into Toronto I met up with an old friend for dinner. She recently switched career paths and is about to finish her graduate program and start an internship. She is so passionate about her work that I left her company entirely inspired. It is amazing to know people who are blissfully doing exactly what they're supposed to be doing. I was reminded why I am in grad school as well-- to pursue awesome science. Sometimes that motivation gets lost in the day to day crap you have to put up with, so it's important to step back to that bigger picture from time to time.

Rather than spending so much money on a hotel close to the conference site, I stayed in a dorm on the University of Toronto campus. The atmosphere reminded me of how enthusiastic and hardcore I was as an undergraduate, and was again an inspiration to tackle the conference head on. It also afforded me the opportunity to walk through Chinatown every day. You know it's authentic when some of the signs don't even bother having nominal English translations on them and you spend the morning commute dodging little old ladies buying groceries at the street market. I can attest for the deliciousness of the veggie dumplings and hot and sour soup.

I also got a lot better at exercising my networking skills this year at IMFAR than at previous conferences. Trust me, I still have a long way to go. This is an entirely accurate representation of me awkwardly trying to mingle with big wigs. (PS-- That tumblr is the best tumblr.) But at least this time I was trying harder! And sometimes even succeeding. I even struck up a potential future collaboration! 

I gotta say, though, my favorite part of the first night's reception wasn't the mingling but the musical entertainment. There was the Maplewood Drum Band, a keyboarder (with whom the audience sang along to the chorus of J Bieb's "Baby"), and a guitarist/ singer (with whom the audience sang along to the chorus of "Hallelujah"). All of the performers were filled with such infectious joy! I was so happy to get many high fives from them afterwards. 

For the first time I also took full advantage of social media at a conference. Of course I couldn't be at all of the simultaneous talks, but I could bet that someone was live tweeting it! There were so many people contributing to #imfar2012 and #imfar, but the ones I got the most value from included @Aspieadvocate, @AutismRealityNB, @AutismScienceFd, @Autism_Women, @CorinaBecker, @DrBrocktagon, @ejwillingham, @GreenOdonata, @GuyHorev, @jennyalice, @johnrobison, @marjorie_m, @mosaicofminds, @Peter_Autisme, @shannonrosa, and @thinkingautism. I also loved getting to meet some of my online friends in real life-- tweeps now peeps, as @DrBrocktagon put it. I tweeted about my posters, and one of the visitors even said "I think I finally understand the point of Twitter." Indeed. 

I think one of the biggest challenges of this conference was science communication. After taking a professional communication course last fall, I'm pretty much ruined for watching standard talks or looking at standard posters now. I have such higher expectations than I used to. In brief: Don't bury your hook. Use visuals (graphs, pictures, and especially videos). Don't read us your slides. And use fewer words. For goodness sake, fewer words! I mean it, take out the words. No one's reading them.

Another challenge more unique to IMFAR was the diversity of the audience. In addition to the usual crowd of scientists/ researchers, post docs, and students, there were also various "stakeholders," as the programmers officially referred to them. These included autistic adults, family members, teachers, therapists, and others in the autism community. I think that's awesome. But it did cause some palpable friction. Stakeholders were often upset that scientists weren't communicating their message clearly in comprehensible terms. Scientists were sometimes frustrated that their conference was being "invaded" by non-scientists and they were now expected to communicate with a broader audience than they're used to. I have no perfect solution here, but I do think it's an important consideration for the conference planners to take into account next year. My only idea is to have a pre-conference session open to stakeholders to learn vocabulary and background concepts that could help them better understand the data being presented over the next few days...

Now for the two biggest frustrations of my trip. I was unwittingly pulled into some autism language wars. I respectfully use the term autistic, but I don't take strong offense at those who use person-first language instead (e.g., "person with autism"). If appropriate to the setting, I might gently broach the subject, but unless it's pertinent to the topic under discussion, I tend not to. (I recently read a blog post that perfectly expressed this point, but I can't remember where it was or find it now. Can anyone help me out? Edit: this.) One of the people who visited my poster did not, apparently, follow the same rule. Here's how the "conversation" went down:

-Me: "...autistic individuals..."

-Her: "You mean individuals with autism."

-Me: "Sorry, I respectfully disagree. Getting back to my data..."

-Her: "Well, many of our parents would be furious with that language."

-Me: "Yes I know, but it's also true that many autistic individuals are..."

-Her: "No." *Storms off* 

Well then. So much for learning anything from one another.

I was also privileged enough to experience science sexism for the first time (consciously, anyhow). A visitor at my poster and I discovered that we knew a colleague in common. His first comment was that she is "one of the few woman academics who knows what lipstick is," which he followed up with further remarks on her style and hair. Instead of talking about her massive contributions to the field, she was objectified into clothes and lipstick. All other women academics were also indirectly denigrated as frumpy fuggos. I was so taken aback that I didn't know what to say and just half heartily laughed along. I regret that now. We need to keep standing up to and challenging this pervasive mentality. Ugh.

OK I've been alluding to them long enough, let's talk directly about my posters! They both went well. I got lots of great feedback and encouragement to go on and formally publish the work. (In addition to the scientific comments, I also got some compliments on my design. Two cheers again for the professional communication course!) One had a lot more traffic than the other, though. As a rough index, at poster 1, 63 handouts were taken, and at poster 2, only 47 handouts were taken. Several non-exclusive hypotheses: timing (day 1 vs. day 2, other talks going on), location (middle vs. back of the room), and topic (prenatal influences vs. sensory symptoms). Who knows.

The biggest highlights for me data-wise were the multiple sessions on the upcoming DSM-5 criteria for autism. I learned about so much in three packed days of posters and talks, but there's just not room and time to talk about it all. If I get any specific requests or questions, I could write some follow up posts, though! But for now, DSM-5 stuff only. 

The main message from Dr. Susan Swedo (the head of the DSM-5 ASD committee) was, and I quote, "Chill out. DSM-5 is not that different from DSM-IV." She also reiterated the important point that DSM-IV isn't a gold standard of diagnosis, and if it were, they wouldn't have been asked to fix it. Keep that in mind. 

Major change 1: Instead of Autistic Disorder, Asperger's Disorder, and Pervasive Developmental Disorder-Not Otherwise Specified as in DSM-IV, DSM-5 combines these into one Autism Spectrum Disorder category. This is justified because, clinically, "High Functioning Autism," Asperger's, and PDD-NOS are not actually differentiated. Clinicians understand and use the labels differently and inconsistently, so there isn't much of a point to them from a scientific viewpoint. 

Major change 2: Instead of a triad, DSM-5 only has two categories of symptoms: social communication skills and restrictive/ repetitive behavior. This makes sense because the prior categories of social skills and communication skills were never really separable in the first place. All factor analyses indicate a two factor structure, not three.

It is true that some people will no longer meet criteria for an ASD under DSM-5 who would have met some sort of PDD under DSM-IV. Unlike the scare articles in the popular media lately, however, data from the field trials indicate that this will likely be a small portion of individuals. Additionally, nearly all of these individuals would meet criteria for the newly created Social Communication Disorder. Furthermore, some individuals who would have been missed under DSM-IV now do qualify for an ASD under DSM-5!

Finally, the data from the initial field trials show that clinicians are able to diagnose ASD with a fair degree of reliability-- better than most other disorders in the DSM, in fact. In all, I'm satisfied with the upcoming changes in how autism will be diagnosed in DSM-5. The changes are backed by data and the hysteria seems to be misplaced.

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And so ends my first foray into the world of blogging. It took way longer to write than I care to admit. I hope someone somewhere got something out of it! Please comment with your reactions, questions, and suggestions. I don't really have a plan in terms of how often I'll post or what the subject matter will always be. I suspect that will evolve for a while before I eventually settle into a pattern... Sit back and enjoy, and share with your friends!