LEE, S. H., Ripke,S.; Cross-Disorder Group of the Psychiatric Genomics Consortium (PGC-CDG), Neale, B. M., Faraone, S. V., Purcell, S. M., International Inflammatory Bowel Disease Genetics Consortium (IIBDGC), Smoller ,J. W., Kendler, K. S,; Wray, N. R., (2013)**

Genetic relationship between five psychiatric disorders estimated from genome-wide SNPs. Nature Genetics, 45, 984-994.

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Introduction: Most psychiatric disorders are heritable. -- The degree to which genetic variants are unique to individual disorders vs. being shared across disorders is unclear.

Methods: We used genome-wide genotype data from the Psychiatric Genomics Consortium (PGC) of cases and controls for schizophrenia (SCZ), bipolar disorder (BPD), major depressive disorder (MDD), autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder ( ADHD).

We applied univariate and bivariate methods for estimation of genetic variation within, and covariation between, disorders.

1 - Single nucleotide polymorphisms (SNPs) explained between 17% and 29% of the variance in liability.

2 - The genetic correlation calculated from SNPs was high for SCZ/BPD (0.68±0.04), moderate for SCZ/MDD (0.43±0.06), BPD/MDD (0.47±0.06), ADHD/MDD (0.32±0.07) low between SCZ/ASD (0.16±0.06) and non-significant for other pairs of disorders, and as a negative control, for psychiatric disorders with a non-psychiatric disease (Crohn's Disease).


[Remarkable was a) the small SNP heritability with respect to that reported for twin studies (ADHD 0.29 vs. 0.76 : SCZ 0.23 vs. 0.81), also b) the lack of overlap between autism and ADHD, although we found the expected lack of overlap of ADHD with SCZ]

This empirical evidence for a shared genetic etiology between psychiatric disorders can inform nosology and encourages investigation of common pathophysiologies for the related disorders.

[** There are 257 authors, see list on the pdf of the article (with RDO as 186th)]