when you realize that the genetic risk of that allele you carry was calculated using a small population from south-western-upper-middle-eurasia-stan … and doesn’t really apply to your individual situation.

“As it happens, … It turned out that I had a genetic variant that implied a moderately increased risk of meningioma, the second most common type of brain tumor.

The information came a little late to be useful. Last summer, … found me half conscious on the floor. The diagnosis at the local hospital was meningioma, a benign (i.e. non-cancerous) tumor inside my skull but fortunately outside my brain.”

Brain-function genes can be very large.  Genetic variation – specifically, copy number variation (CNV) - is often found in brain-function genes in populations with mental disability … but … not much more often than in healthy populations.

To demonstrate the potential impact of confounders, we genotyped rare CNV events in 2,415 unaffected controls with Affymetrix 6.0; we then applied standard pathway analyses using four sets of brain-function genes and observed an apparently highly significant enrichment for each set. The enrichment is simply driven by the large size of brain-function genes.

The full story and a new statistical test – that aims to control for this confounding effect of large brain-function genes.  More on chromosomal structural variation and schizophrenia here.

The mission of the Encyclopedia of DNA Elements (ENCODE) Project is to enable the scientific and medical communities to interpret the human genome sequence and apply it to understand human biology and improve health. The ENCODE Consortium is integrating multiple technologies and approaches in a collective effort to discover and define the functional elements encoded in the human genome, including genes, transcripts, and transcriptional regulatory regions, together with their attendant chromatin states and DNA methylation patterns. In the process, standards to ensure high-quality data have been implemented, and novel algorithms have been developed to facilitate analysis. Data and derived results are made available through a freely accessible database. Here we provide an overview of the project and the resources it is generating and illustrate the application of ENCODE data to interpret the human genome.

“The historical lack of success in genetic studies of complex disease can largely be attributed, not to ignored biological interactions, but rather to under-powered studies that surveyed only a fraction of genetic variation …”

thanks for the pic heckyeahart

One of the best research teams in the business performed a genomewide association study (GWAS) of neuroticism in 1,227 US Caucasion participants and found associations (P values of 10−5 to 10−6) with several markers – including rs7151262 in the MAMDC1 gene.  Later they replicated the finding in a German sample of 1,880 (P values in the same directions 0.006–0.025).

Very exciting to ponder the ways in which this SNP might relate to the development of brain systems that process emotional information!

More recently, they attempted another replication of the MAMDC1 gene for association with neuroticism in 2,722 US Caucasion participants.  This time they report, “the current analysis failed to detect a significant association signal“.

Some 5,829 people were involved in the research and the data suggest that rs7151262 may or may not contribute to one’s neurotic tendencies.  If you knew your rs7151262 genotype would it change the way you think about yourself?

I don’t know … the confusion over the (+) vs. (-) association data would make me … well, neurotic.

thanks for the photo jinxmesomethingcrazy.

“For example, have you thought about epigenetic effects that might be environmentally induced and can be transmitted across multiple subsequent generations?  Genotypes of individuals in previous generations might even be a better predictor of phenotype than an individual’s own genotype.”

“I know that Copy-Number Polymorphic (CNP) duplications are highly variable among individual and are considered inaccessible by most existing genotyping and sequencing technologies, but I’m still getting my genome sequenced anyway.”

“Can you please help Eric understand that rare variants and large variants (deletions, duplications and inversions) are individually rare, but collectively common in the human population might account for much more of heritability than common variation.  Nothing is known about these rare variants!”

“Yeah, Eric doesn’t realize that a very large number of closely linked genes can exhibit context-dependent and non-additive effects.”

“Gene by environment innnterraaaaactiiooon … coooool.”

–real science here.