In a large Scottish pedigree a balanced translocation t (1 11)(q42 1 q14 3) disrupting the DISC1 and DISC2 genes segregates with major mental illness including schizophrenia and depression A frame-shift carboxyl-terminal deletion was reported in DISC1 in an American family with schizophrenia but subsequently found in two controls Herein we test one hypothesis utilizing a large scale case-control mutation analysis uncommon DISC1 variants are associated with high risk for bipolar spectrum disorder We have analyzed the regions of likely functional significance in the DISC1 gene in 504 patients with bipolar spectrum disorder and 576 ethnically similar controls Five patients were heterozygous for ultra-rare protein structural variants not found in the 576 controls (p = 0 02 one-sided Fisher s exact test) and shown to be ultra-rare by their absence in a pool of 10 000 control alleles In our sample ultra-rare (private) protein structural variants in DISC1 are associated with an estimated attributable risk of about 0 5% in bipolar spectrum disorder These data are consistent with (i) the high frequency of depression in the large Scottish family with a translocation disrupting DISC1 (ii) linkage disequilibrium analysis demonstrating haplotypes associated with relatively small increases in risk for bipolar disorder (<3-fold odds ratio) The data illustrate how low/moderate risk haplotypes that might be found by the HapMap project can be followed up by resequencing to identify protein structural variants with high risk low frequency and of potential clinical utility (C) 2010 Elsevier Ireland Ltd All rights reserved

Background: Fibromyalgia syndrome (FMS), a common, chronic, widespread musculoskeletal pain disorder found in 2% of the general population and with a preponderance of 85% in females, has both genetic and environmental contributions. Patients and their parents have high plasma levels of the chemokines MCP-1 and eotaxin, providing evidence for both a genetic and an immunological/inflammatory origin for the syndrome (Zhang et al., 2008, Exp. Biol. Med. 233: 1171-1180).Methods and Findings: In a search for a candidate gene affecting inflammatory pathways, among five screened in our patient samples (100 probands with FMS and their parents), we found 10 rare and one common alleles for MEFV, a gene in which various compound heterozygous mutations lead to Familial Mediterranean Fever (FMF). A total of 2.63 megabases of genomic sequence of the MEFV gene were scanned by direct sequencing. The collection of rare missense mutations (all heterozygotes and tested in the aggregate) had a significant elevated frequency of transmission to affecteds (p = 0.0085, one-sided, exact binomial test). Our data provide evidence that rare missense variants of the MEFV gene are, collectively, associated with risk of FMS and are present in a subset of 15% of FMS patients. This subset had, on average, high levels of plasma IL-1 beta (p = 0.019) compared to FMS patients without rare variants, unaffected family members with or without rare variants, and unrelated controls of unknown genotype. IL-1 beta is a cytokine associated with the function of the MEFV gene and thought to be responsible for its symptoms of fever and muscle aches.Conclusions: Since misregulation of IL-1 beta expression has been predicted for patients with mutations in the MEFV gene, we conclude that patients heterozygous for rare missense variants of this gene may be predisposed to FMS, possibly triggered by environmental factors.

The causes of schizophrenia remain elusive. In a large Scottish pedigree, a balanced translocation t(1;11) (q42.1;q14.3) disrupting the DISC1 and DISC2 genes segregates with major mental illness, including schizophrenia and unipolar depression. A frame-shift carboxyl-terminal deletion was reported in DISC1 in an American family, but subsequently found in two controls. A few common structural variants have been associated with less than a 2-fold increased risk for schizophrenia, but replication has not been uniform. No large scale case-control mutation study has been performed. We have analyzed the regions of likely functional significance in the DISC1 gene in 288 patients with schizophrenia and 288 controls (5 megabases of genomic sequence analyzed). Six patients with schizophrenia were heterozygous for ultra-rare missense variants not found in the 288 controls (p=0.015) and shown to be ultra-rare by their absence in a pool of 10,000 control alleles. We conclude that ultra-rare structural variants in DISC1 are associated with an attributable risk of about 2% for schizophrenia. In addition, we confirm that two common structural variants (Q264R and S704C) elevate the risk for schizophrenia slightly (odds ratio 1.3, 95% CI: 1.0-1.7). DISC1 illustrates how common/moderate risk alleles suggested by the HapMap project might be followed up by resequencing to identify genes with high risk, low frequency alleles of clinical relevance.

Although DOVAM-S (detection of virtually all mutations–SSCP) in effect detects all mutations and is less costly than direct sequencing, the technique currently requires the use of radioactivity. F-DOVAM-S (fluorescent DOVAM-S) was developed to replace the isotopic label with fluorescence and to increase throughput via dye color multiplexing. As proof of principle, two multitemperature slab gel electrophoresis conditions were evaluated through the blinded analysis of mutations in the factor IX (FIX) genes of 88 hemophilia B (HB) patients and 7 wild-type controls. Using only two conditions, it was determined that F-DOVAM-S had a detection sensitivity of 97%. It is anticipated that when three or four optimized conditions are employed, F-DOVAM-S will detect all mutations. Three patient samples were multiplexed per well using three different fluorescent dyes (6FAM, VIC, and NED), demonstrating that it is possible to analyze up to 44 kb of diploid, color-coded amplification product per gel lane. This value corresponds to a throughput of approximately 4 Mb of DNA analyzed per 96-well gel, which is approximately triple that of conventional radiolabeled DOVAM-S. Throughput is further enhanced by the rapidity at which the fluorescent signal can be captured and the resultant multicolor chromatograms analyzed. Given these data, F-DOVAM-S has the potential to be a particularly powerful technology for clinical diagnosis because it allows the mutation analysis of multiple patients to be performed within 24 h.

Aminoglycosides can bypass nonsense mutations and are the prototypic agents for translational bypass therapy (TBT). Initial results demonstrate the need for more potent drugs and an in vivo model system for quantitative assessment of TBT. Herein, we present an in vivo system for evaluating the efficacy of premature stop codon management therapies: in vivo quantitative stop codon management repli-sampling TBT efficacy assay (IQSCMaRTEA). Application of IQSCMaRTEA reveals that geneticin is much more efficacious in vivo than gentamicin. Treatment with geneticin elicits a multiday response, and residual F9 antigen can be detected after 3 weeks. These data demonstrate the utility of IQSCMaRTEA for evaluating drugs that bypass nonsense mutations. In addition, IQSCMaRTEA may be helpful for testing inhibitors of nonsense-mediated decay, as stop codon management therapy will sometimes require inhibition of nonsense-mediated decay and translational bypass of the nonsense mutation. Furthermore, geneticin, its metabolites, or better tolerated analogues should be evaluated as a general treatment with multiday response for severe genetic disease caused by nonsense mutation.

Neuroligins are postsynaptic membrane cell-adhesion molecules which bind to beta-neurexins, a family of proteins that act as neuronal cell surface receptors. To explore the possibility that structural variants in the beta-neurexin genes predispose to autism, the coding regions and associated splice junctions of three beta-neurexin genes were scanned with detection of virtually all mutations-SSCP (DOVAM-S) in 72 Caucasian patients with autism. In addition, segments of the neurexin 1beta gene were sequenced in 131 additional Caucasian and 61 Afro-American patients with autism from South Carolina and the Midwest. Two putative missense structural variants were identified in the neurexin 1beta gene in four Caucasian patients with autism and not in 535 healthy Caucasian controls (4/203 vs. 0/535, P=0.0056). Initial family data suggest that incomplete penetrance may occur. In addition, no structural variant was found in the neurexin 2beta gene and the neurexin 3beta gene. In the context of all available data, we conclude that mutations of the neurexin 1beta gene may contribute to autism susceptibility.