Tetrasomy 13q31.1qter due to an inverted duplicated neocentric marker chromosome in a fetus with multiple malformations

Am J Med Genet A. 2012 Apr;158A(4):894-900. doi: 10.1002/ajmg.a.35258. Epub 2012 Mar 14.

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.

Publication types

  • Case Reports

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Cerebellum / abnormalities
  • Chromosome Banding
  • Chromosome Inversion*
  • Chromosomes, Human, Pair 13 / genetics*
  • Comparative Genomic Hybridization
  • Female
  • Fetus / abnormalities*
  • Genetic Association Studies
  • Humans
  • In Situ Hybridization, Fluorescence
  • Karyotype
  • Lymphangioma, Cystic
  • Male
  • Pregnancy
  • Pregnancy Complications / genetics
  • Tetrasomy*
  • Ultrasonography, Prenatal