BackgroundDetection of submicroscopic chromosomal alterations in patients with a idiopathic intellectual disability (ID) allows significant improvement in delineation of the regions of the genome that are associated with brain development and function. However, these chromosomal regions usually contain several protein-coding genes and regulatory elements, complicating the understanding of genotype-phenotype correlations. We report two siblings with ID and an unrelated patient with atypical autism who had 3p26.3 microdeletions and one intellectually disabled patient with a 3p26.3 microduplication encompassing only the CNTN6 gene.ResultsTwo 295.1-kb microdeletions and one 766.1-kb microduplication of 3p26.3 involving a single gene, CNTN6, were identified with an Agilent 60K array. Another 271.9-kb microdeletion of 3p26.3 was detected using an Affymetrix CytoScan HD chromosome microarray platform. The CHL1 and CNTN4 genes, although adjacent to the CNTN6 gene, were not affected in either of these patients.ConclusionsThe protein encoded by CNTN6 is a member of the immunoglobulin superfamily and functions as a cell adhesion molecule that is involved in the formation of axon connections in the developing nervous system. Our results indicate that CNTN6 may be a candidate gene for ID.Electronic supplementary materialThe online version of this article (doi:10.1186/s13039-014-0097-0) contains supplementary material, which is available to authorized users.
Background: The majority of miscarriages are sporadic; however, 1-5% of couples experience recurrent pregnancy loss (RPL). Approximately 50-60% of miscarriages result from chromosomal abnormalities. Currently, there are conflicting reports regarding the rates of chromosomal abnormalities between recurrent and sporadic pregnancy losses. Methods: A retrospective comparative cytogenetic analysis of 442 RPL and 466 sporadic abortions (SA) was performed. Maternal age and medical background were evaluated, and chromosomal abnormality rates were compared between groups. Results: The frequency of embryos with abnormal karyotypes was significantly higher in SA compared to RPL (56.7 and 46.6%, respectively), and abortions from women under 30 years of age were the main contributor to this difference. An age-dependent increase in the abnormal karyotype rate was observed in two groups of women - those with SA [53.0 and 70.1% for younger and older (≥35-year-old) mothers, respectively] and those with idiopathic RPL without any concomitant reproductive pathology (46.5 and 78.4% for younger and older mothers) - but not in the group of women with RPL associated with concomitant reproductive pathology. The incidence of recurrent abnormal karyotypes in subsequent miscarriages was significantly higher than random probability (odds ratio = 22.75). Conclusion: Our findings highlight the variability in the risk of aneuploidy in recurrent abortion.