TrisomyChromosomesChromosome MappingDown SyndromeChromosome BandingChromosome AberrationsChromosomes, Human, Pair 21X ChromosomeKaryotypingChromosomes, Human, Pair 18Chromosome DisordersChromosomes, Human, Pair 13Chromosomes, Human, 16-18Chromosomes, Human, 6-12 and XSex ChromosomesChromosomes, Human, Pair 1Chromosomes, Human, Pair 7Chromosomes, HumanChromosomes, Human, Pair 11Chromosomes, Human, Pair 17Chromosomes, Human, 13-15Chromosomes, BacterialChromosomes, Human, Pair 9Chromosome DeletionChromosome SegregationChromosomes, Human, Pair 8Chromosomes, Human, Pair 6Chromosomes, Human, Pair 12Chromosomes, Human, 21-22 and YIn Situ Hybridization, FluorescenceChromosomes, Human, Pair 16Chromosomes, Human, 1-3Chromosomes, Human, Pair 22Chromosomes, Human, Pair 2Chromosomes, Human, Pair 10Chromosomes, PlantChromosomes, FungalChromosomes, Human, Pair 4Chromosomes, Human, Pair 5MosaicismChromosomes, MammalianChromosomes, Human, Pair 19Chromosome PairingAbnormalities, MultipleChromosomes, Human, Pair 15Chromosomes, Human, YChromosomes, Human, Pair 20Chromosomes, Human, XChromosomes, Human, 4-5Nondisjunction, GeneticChromosomes, Human, Pair 14AneuploidyPrenatal DiagnosisChromosomes, Artificial, BacterialTranslocation, GeneticChromosome PaintingChromosomes, Human, 19-20Genetic MarkersGenetic LinkageChromosome InversionChromosomes, Artificial, YeastChromosome BreakageRing ChromosomesNuchal Translucency MeasurementMolecular Sequence DataBase SequenceChorionic Gonadotropin, beta Subunit, HumanChromosome PositioningMaternal AgeMeiosisPregnancy Trimester, FirstPregnancyMonosomyUltrasonography, PrenatalFetal DiseasesPedigreeX Chromosome InactivationPhenotypeCentromereMetaphasePregnancy Trimester, SecondPregnancy-Associated Plasma Protein-AChromosomes, InsectRecombination, GeneticNasal BoneHybrid CellsMutationDermatoglyphicsMitosisAmniocentesisChromosome StructuresDNAMicrosatellite RepeatsPregnancy, High-RiskAllelesCytogenetic AnalysisCytogeneticsIntellectual DisabilityLod ScoreCrosses, Genetic