Multiplex ligation dependent probe amplification (MLPA) for rapid distinction between unique sequence positive and negative marker chromosomes in prenatal diagnosis

Background: Small supernumerary marker chromosomes (sSMC) are extra structurally abnormal chromosomes that cannot be unambiguously identified with conventional chromosome banding techniques. These marker chromosomes may cause an abnormal phenotype or be harmless depending on different factors such as genetic content, chromosomal origin and level of mosaicism. When a sSMC is found during prenatal diagnosis, the main question is whether the sSMC contains euchromatin since in most cases this will lead to phenotypic abnormalities. We present the use of Multiplex Ligation Dependent probe Amplification (MLPA) for rapid distinction between non-euchromatic and euchromatic sSMC. Results: 29 well-defined sSMC found during prenatal diagnosis were retrospectively investigated with MLPA with the SALSA MLPA centromere kits P181 and P182 as well as with the SALSA MLPA telomere kits P036B and P070 (MRC Holland BV, Amsterdam, The Netherlands). All unique-sequence positive sSMC were correctly identified with MLPA, whereas the unique-sequence negative sSMC had normal MLPA results. Conclusions: Although different techniques exist for identification of sSMC, we show that MLPA is a valuable adjunctive tool for rapidly distinguishing between unique-sequence positive and negative sSMC. In case of positive MLPA results, genetic microarray analysis or, if not available, targeted FISH can be applied for further identification and determination of the exact breakpoints, which is important for prediction of the fetal phenotype. In case of a negative MLPA result, which means that the sSMC most probably does not contain genes, the parents can already be reassured and parental karyotyping can be initiated to assess the heritability. In the mean time, FISH techniques are needed for determination of the chromosomal origin

Vier scenario’s voor de inrichting van Nederland in 2050 : Ruimtelijke Verkenning 2023

In de Ruimtelijke Verkenning 2023 heeft het PBL scenario’s ontwikkeld voor de inrichting van Nederland in 2050. In dit hoofdrapport worden vier mogelijke ruimtelijke toekomsten gepresenteerd. Dat zijn: Mondiaal Ondernemend (een toekomstscenario waarin grote bedrijven de lead hebben), Snelle Wereld (de nog verder toegenomen digitalisering doet afstanden verdwijnen), Groen Land (veel ruimte voor de natuur) en Regionaal Geworteld (burgers nemen het initiatief in hun eigen leefomgeving). Voor elk scenario zijn op basis van ruimtelijke modellering en ontwerpend onderzoek gedetailleerde kaarten van het bijbehorende Nederland van 2050 gemaakt. Deze scenariokaarten brengen in beeld welke gevolgen verschillende keuzes hebben