Chapters authored
Gender Affects Clinical Suspicion of Down Syndrome
Part of the book: Prenatal Diagnosis and Screening for Down Syndrome
Resolving Paradoxes of Robertsonian Translocations
Since Robertsonian translocations (ROB) are essential in the etiology of congenital malformations and reproductive disorders, it is natural to assume that they represent a thoroughly studied subject. However, on closer inspection, there are poorly studied areas within this field. The aim of this report is to present results of a comprehensive analysis of available data collected by researchers worldwide that allows a new look at the problems mentioned above. There were determined rates and spectrums of ROB in the general population and in patients with reproductive disorders. The comprehension of a female-based sex ratio (male-to-female ratio) among newborn carriers of balanced nonhomologous ROB in the general population leads to a conclusion on the mechanism of sex-specific correction of translocation trisomy, which might explain both inexplicably low occurrence of rob-associated uniparental disomy and phenomenon of “non-Mendelian-inheritance.” The data obtained indicate that female ROB carriers are at a much higher risk of uniparental disomy compared to male ROB carriers. In the majority of asymptomatic male carriers of homologous translocation/isochromosome (HT), spermatogenesis is not impaired. An analysis of sex ratio among ill-defined HT carriers showed a difference between patients with Prader-Willi syndrome and Angelman syndrome, indicating different mechanisms of HT formation.
Part of the book: Cytogenetics