Genetic variation in DNMT3B and increased global DNA methylation is associated with suicide attempts in psychiatric patients
GENES BRAIN AND BEHAVIOR
Authors: Murphy, T. M.; Mullins, N.; Ryan, M.; Foster, T.; Kelly, C.; McClelland, R.; O'Grady, J.; Corcoran, E.; Brady, J.; Reilly, M.; Jeffers, A.; Brown, K.; Maher, A.; Bannan, N.; Casement, A.; Lynch, D.; Bolger, S.; Buckley, A.; Quinlivan, L.; Daly, L.; Kelleher, C.; Malone, K. M.
Abstract
Recently, a significant epigenetic component in the pathology of suicide has been realized. Here we investigate candidate functional SNPs in epigenetic-regulatory genes, DNMT1 and DNMT3B, for association with suicide attempt (SA) among patients with co-existing psychiatric illness. In addition, global DNA methylation levels [5-methyl cytosine (5-mC%)] between SA and psychiatric controls were quantified using the Methylflash Methylated DNA Quantification Kit. DNA was obtained from blood of 79 suicide attempters and 80 non-attempters, assessed for DSM-IV Axis I disorders. Functional SNPs were selected for each gene (DNMT1; n?=?7, DNMT3B; n?=?10), and genotyped. A SNP (rs2424932) residing in the 3' UTR of the DNMT3B gene was associated with SA compared with a non-attempter control group (P?=?0.001; Chi-squared test, Bonferroni adjusted P value?=?0.02). Moreover, haplotype analysis identified a DNMT3B haplotype which differed between cases and controls, however this association did not hold after Bonferroni correction (P?=?0.01, Bonferroni adjusted P value?=?0.56). Global methylation analysis showed that psychiatric patients with a history of SA had significantly higher levels of global DNA methylation compared with controls (P?=?0.018, Student's t-test). In conclusion, this is the first report investigating polymorphisms in DNMT genes and global DNA methylation quantification in SA risk. Preliminary findings suggest that allelic variability in DNMT3B may be relevant to the underlying diathesis for suicidal acts and our findings support the hypothesis that aberrant DNA methylation profiles may contribute to the biology of suicidal acts. Thus, analysis of global DNA hypermethylation in blood may represent a biomarker for increased SA risk in psychiatric patients.
Familial transmission of 5p13.2 duplication due to maternal der(X)ins(X;5)
EUROPEAN JOURNAL OF MEDICAL GENETICS
Authors: Walters-Sen, Lauren C.; Windemuth, Kathy; Angione, Katie; Nandhlal, Jenisha; Milunsky, Jeff M.
Abstract
Submicroscopic duplications of 5p13 have been recently reported in several cases, warranting the description of a new clinical entity (Chromosome 5p13 Duplication Syndrome; MIM 613174). These microduplications, while variable in size, all contain at least part of the NIPBL gene. Patients with duplications in this region present with intellectual disability/developmental delay (ID/DD) and dysmorphic facies. In addition, skeletal and brain abnormalities have been variably reported, as well as propensity for obesity in adulthood and hypotonia. We report a family with two affected sons and two affected daughters, each carrying a duplication at 5p13.2 encompassing the 30 portion of SLC1A3 and the 5' portion of NIPBL. Upon confirming the SNP microarray finding by FISH in the proband, it was discovered that the 5p13.2 duplication was located on the short arm of the X chromosome. Further FISH studies on the family demonstrated that all affected children and their mother carried a derivative X chromosome with insertion of material from 5p13.2 into the intermediate region of Xp [der(X)ins(X;5)(p2?2.1;p13.2p13.2)]. To our knowledge, this is the first report of an inherited duplication of 5p13.2 with multiple affected family members. This family underscores the need to confirm array findings by FISH, both in the proband and family members, to discern implications for pathogenicity and more accurately define the recurrence risk. (C) 2015 Elsevier Masson SAS. All rights reserved.