The Genetics of Bipolar Disorder: What A Tangle

Here's a brave attempt to look for genetic markers of bipolar disorder. The authors studied 388 Old Order Amish sufferers, doing thorough SNP analysis on the lot and total sequencing on fifty of them. There were many parent-child relationships in the set, which gave a chance for further discrimination. And the result: . . .despite the in-depth genomic characterization of this unique, large and multigenerational pedigree from a genetic isolate, there was no convergence of evidence implicating a particular set of risk loci or common pathways. The striking haplotype and locus heterogeneity we observed has profound implications for the design of studies of bipolar and other related disorders. If you look around the literature, you'll find numerous smaller studies also trying to find genetic markers for bipolar disorder, and many of these propose possible candidate loci. But very few of them seem to agree, and this new study doesn't seem to confirm any of them. The authors hold out some hope for still larger cohorts and more comprehensive sequencing, and that's certainly the way to go. But if there were anything close to a simple genetic sequence for bipolar disorder, it would have been found by now. Like many other diseases (and not just those of the central nervous system), it's probably a phenotype that can be realized by a whole range of mechanisms, an alternate state of physiology that the system can slip into through a combination of genetic and environmental effects. And ...
Source: In the Pipeline - Category: Chemists Tags: The Central Nervous System Source Type: blogs