title: Chromosome 18 variant with increased centromeric tandemly repeated DNA in a family.
abstract: At amniocentesis of a woman in her forties, a familial abnormal chromosome 18 is found. The very elongated short arm is shown to consist partially of centromeric heterochromatin of 18 by specific DNA probe. The newborn develops normally.
mesh_terms: D000328:Adult; D000368:Aged; D002503:Centromere / Q000648:ultrastructure*; D002648:Child; D002871:Chromosome Banding; D002875:Chromosomes / Q000648:ultrastructure*; D002887:Chromosomes, Human, Pair 18; D004247:DNA / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D006570:Heterochromatin / Q000648:ultrastructure; D006801:Humans; D007621:Karyotyping; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D010375:Pedigree; D011247:Pregnancy; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D006570:Heterochromatin; D004247:DNA