The eponymus Trisomy 18 is

(D) Edward's syndrome EXAMPLES OF CHROMOSOMAL DISORDERSChromosomesResult2n (46, XX)Normal female2n (46, XY)Normal maleNUMERICAL ABNORMALITIESTriploidy (3n), tetraploidy (4n)Spontaneous abortionParthenogenesis (2n from same parent)Spontaneous abortionAneuploidy (2n + specific chromosome) Trisomy 21 (47, XY,+21)Down's syndrome (characteristic facies, IQ usually < 50, congenital heart disease, reduced life expectancy)Trisomy 18 (47, XY, +18)Edwards'syndrome (characteristic skull and facies, frequent malformations of heart, kidney and other organs)Trisomy 13(47, XY,+13)Patau's syndrome (cleft lip and palate, polydactyly, small head, frequent congenital heart disease)Sex Chromosome Aneuploidies Phenotypically male 47, XXYKlinefelter's syndrome (infertility, gynaecomastia, small testes)47, XYYXYY male (usually asymptomatic, often tall)Phenotypically female 47, XXXTrisomy X (usually asymptomatic, 20% mentally handicapped)45, X0Turner's syndrome (short stature, webbed neck, primary amenorrhoea)STRUCTURAL CHROMOSOME ABERRATIONSInherited 46, XY, del(5p)Cri du chat syndrome, deletion of short arm of chromosome 545, XY,t(14;21)Fusion of 14 and 21, no essential chromosomal material lost (NORMAL, but balanced carrier of abnormal chromosome)46, XY, t(14;21)Fused 14;21 chromosome has segregated into gamete with normal chromosome 21, and fertilisation has generated trisomy 21 (Down's syndrome)AcquiredOccur in over 50% of haematological malignancies; also common in other neoplastic cells46, XY, t(9,22)Philadelphia chromosome (chronic myeloid leukaemia)46, XY, t(2,8) or t(8,14) or t(8,22)Burkitt's lymphoma