Meiotic segregation and interchromosomal effect in the sperm of a double translocation carrier: a case report

Abstract Background Infertility is a natural mechanism of selection intended to prevent the delivery of a child with malformations or mental retardation. Male infertility is closely related to chromosomal abnormalities. This study was focused on the analysis of meiotic segregation involving a Robertsonian translocation, 45,XY,der(13;13) [56]/45,XY,der(13;14) [44] and the evaluation of possible interchromosomal effects. Results Hybridisation with LSI 13q14 and subtelomere 14q probes and WCP13 SpectrumGreen and WCP14 SpectrumOrange probes showed a high proportion of unbalanced gametes, corresponding to 71.2% of the spermatozoa. The disomic frequencies of the sexual chromosomes and chromosome 18 of the patient were higher (5.28% and 2.55%, respectively) than those of the control (0.6% and 0.59%, respectively). Conclusion Meiotic segregation studies in sperm are an important tool for genetic counselling of chromosomal aberrations, allowing for a prediction of the risks and consequent implications for the reproductive life. The patient with this rare translocation exhibited meiotic segregation fidelity, and a high rate of unbalanced gametes with disomic spermatozoa.

Longitudinal brain volumetric changes during one year in non-elderly healthy adults: a voxel-based morphometry study

Previous cross-sectional magnetic resonance imaging (MRI) studies of healthy aging in young adults have indicated the presence of significant inverse correlations between age and gray matter volumes, although not homogeneously across all brain regions. However, such cross-sectional studies have important limitations and there is a scarcity of detailed longitudinal MRI studies with repeated measures obtained in the same individuals in order to investigate regional gray matter changes during short periods of time in non-elderly healthy adults. In the present study, 52 healthy young adults aged 18 to 50 years (27 males and 25 females) were followed with repeated MRI acquisitions over approximately 15 months. Gray matter volumes were compared between the two times using voxel-based morphometry, with the prediction that volume changes would be detectable in the frontal lobe, temporal neocortex and hippocampus. Voxel-wise analyses showed significant (P < 0.05, family-wise error corrected) relative volume reductions of gray matter in two small foci located in the right orbitofrontal cortex and left hippocampus. Separate comparisons for males and females showed bilateral gray matter relative reductions in the orbitofrontal cortex over time only in males. We conclude that, in non-elderly healthy adults, subtle gray matter volume alterations are detectable after short periods of time. This underscores the dynamic nature of gray matter changes in the brain during adult life, with regional volume reductions being detectable in brain regions that are relevant to cognitive and emotional processes.