title: Tetrasomy 13q31.1qter due to an inverted duplicated neocentric marker chromosome in a fetus with multiple malformations.
abstract: Small supernumerary marker chromosome (sSMC) lacking alpha satellite DNA or endogenous centromere regions are rare and contain fully functional centromeres, called neocentromeres. We report on a woman with a 14-week gestation pregnancy with a cystic hygroma and cerebellar hypoplasia at ultrasound examination. Cytogenetic studies showed a karyotype 47,XY,+mar dn. This sSMC was observed in chorionic villi, lung, and muscle tissue. Array Comparative Genomic Hybridization showed a gain from 13q31.1 to 13qter region. Fluorescent in situ hybridization with pan alpha satellite probe and probes specific for chromosome 13 showed a marker corresponding to an inversion duplication of the 13q distal chromosomal region without alpha satellite DNA sequence, suggesting the presence of a neocentromere. Examination of the fetus showed dysmorphic features, cystic cervical hygroma, postaxial polydactyly of the right hand and left foot with short fingers, malrotation of the gut, and a micropenis with hypospadias. Genotype-phenotype correlation in tetrasomy 13q is discussed according to the four 13q chromosomal breakpoints reported (13q32, 13q31, 13q21, 13q14) for chromosome 13 supernumerary markers.
authors.affiliation: Université Paris-Sud, Service d'Histologie Embryologie et Cytogénétique, APHP, Hôpital Antoine Béclère, Clamart, France. veronique_haddad@yahoo.fr
authors.forename: Véronique
authors.initials: V
authors.lastname: Haddad
authors.forename: Azzedine
authors.initials: A
authors.lastname: Aboura
authors.forename: Lucie
authors.initials: L
authors.lastname: Tosca
authors.forename: Narjes
authors.initials: N
authors.lastname: Guediche
authors.forename: Anne-Elisabeth
authors.initials: AE
authors.lastname: Mas
authors.forename: Aurore Coulomb
authors.initials: AC
authors.lastname: L'Herminé
authors.forename: Luc
authors.initials: L
authors.lastname: Druart
authors.forename: Olivier
authors.initials: O
authors.lastname: Picone
authors.forename: Sophie
authors.initials: S
authors.lastname: Brisset
authors.forename: Gérard
authors.initials: G
authors.lastname: Tachdjian
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D002531:Cerebellum / Q000002:abnormalities; D002871:Chromosome Banding; D007446:Chromosome Inversion; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D055028:Comparative Genomic Hybridization; D005260:Female; D005333:Fetus / Q000002:abnormalities*; D056726:Genetic Association Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D018191:Lymphangioma, Cystic; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000235:genetics; D058670:Tetrasomy; D016216:Ultrasonography, Prenatal