Intellectual DisabilityMental Retardation, X-LinkedFragile X Mental Retardation ProteinFragile X SyndromeAbnormalities, MultipleSyndromeMicrocephalyX ChromosomePedigreeSex Chromosome AberrationsFetal Growth RetardationChromosomes, Human, XFaciesGrowth DisordersConsanguinityAtaxiaDevelopmental DisabilitiesChromosome DeletionPhenotypeMutationEducation of Intellectually DisabledKaryotypingGenetic LinkageMethyl-CpG-Binding Protein 2In Situ Hybridization, FluorescenceRett SyndromeGenes, RecessiveRNA-Binding ProteinsSpasms, InfantileMuscle HypotoniaMolecular Sequence DataChromosome DisordersAutistic DisorderChromosome BandingChromosome AberrationsCraniofacial AbnormalitiesChromosome MappingDown SyndromeEpilepsyHypertelorismBase SequenceFaceInfant, Newbornalpha-ThalassemiaNerve Tissue ProteinsPsychomotor DisordersTrisomyBrainIntelligence TestsRing ChromosomesDNA Mutational AnalysisHeterozygoteHand Deformities, CongenitalColobomaTrinucleotide Repeat ExpansionHemoglobin HTranslocation, GeneticNervous System MalformationsPregnancyHeterozygote DetectionOculocerebrorenal SyndromeTuberous SclerosisFacial BonesInterleukin-1 Receptor Accessory ProteinMonosomySeizuresDosage Compensation, GeneticRubinstein-Taybi SyndromeAngelman SyndromeChromosome BreakageChromosomes, Human, Pair 15IntelligenceMice, KnockoutGenetic Diseases, X-LinkedNeuronsGene DuplicationGenetic TestingPhenylketonuriasCerebellar AtaxiaGene DeletionAmino Acid SequenceCodon, NonsenseCoffin-Lowry SyndromeLanguage Development DisordersMutation, MissenseNuclear ProteinsGenetic MarkersChromosomes, Human, Pair 21Chromosome FragilityReceptors, Metabotropic GlutamateFailure to ThriveDendritic SpinesWAGR SyndromeLearning DisordersDendritesSex Chromosome DisordersRNA, MessengerClassical Lissencephalies and Subcortical Band HeterotopiasSjogren-Larsson SyndromeWolf-Hirschhorn Syndrome