Molecular characterization of 39 de novo sSMC: contribution to prognosis and genetic counselling, a prospective study. (5th April 2013)

• Record Type: Journal Article
• Authors: Marle, N.; Martinet, D.; Aboura, A.; Joly‐Helas, G.; Andrieux, J.; Flori, E.; Puechberty, J.; Vialard, F.; Sanlaville, D.; Fert Ferrer, S.; Bourrouillou, G.; Tabet, A.C.; Quilichini, B.; Simon‐Bouy, B.; Bazin, A.; Becker, M.; Stora, H.; Amblard, S.; Doco‐Fenzy, M.; Molina Gomes, D.; Girard‐Lemaire, F.; Cordier, M.P.; Satre, V.; Schneider, A.; Lemeur, N.; Chambon, P.; Jacquemont, S.; Fellmann, F.; Vigouroux‐Castera, A.; Molignier, R.; Delaye, A.; Pipiras, E.; Liquier, A.; Rousseau, T.; Mosca, A.L.; Kremer, V.; Payet, M.; Rangon, C.; Mugneret, F.; Aho, S.; Faivre, L.; Callier, P.;
• Is Part Of: Clinical genetics. Volume 85:Number 3(2014:Mar.)
• Page Start: 233
• Page End: 244
• Publication Date: 2013-04-05
• Subjects: Medical genetics -- Periodicals; 616.0420
• DOI: 10.1111/cge.12138
• Languages: English
• ISSNs: 0009-9163

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that cannot be characterized by karyotype. In many prenatal cases of <italic>de novo</italic> sSMC, the outcome of pregnancy is difficult to predict because the euchromatin content is unclear. This study aimed to determine the presence or absence of euchromatin material of 39 <italic>de novo</italic> prenatally ascertained sSMC by array‐comparative genomic hybridization (array‐CGH) or single nucleotide polymorphism (SNP) array. Cases were prospectively ascertained from the study of 65, 000 prenatal samples [0.060%; 95% confidence interval (CI), 0.042–0.082]. Array‐CGH showed that 22 markers were derived from non‐acrocentric markers (56.4%) and 7 from acrocentic markers (18%). The 10 additional cases remained unidentified (25.6%), but 7 of 10 could be further identified using fluorescence <italic>in situ</italic> hybridization; 69% of <italic>de novo</italic> sSMC contained euchromatin material, 95.4% of which for non‐acrocentric markers. Some sSMC containing euchromatin had a normal phenotype (31% for non‐acrocentric and 75% for acrocentric markers). Statistical differences between normal and abnormal phenotypes were shown for the size of the euchromatin material (more or less than 1 Mb, p = 0.0006) and number of genes (more or less than 10, p = 0.0009). This study is the largest to date and shows the utility of array‐CGH or SNP array in the detection and characterization of <italic>de novo</italic> sSMC in a prenatal context.</p> </abstract>