title: Prenatal diagnosis of a deletion of 18q in a fetus associated with multiple-marker screen positive results.
abstract: We report here the observations of positive maternal serum screening tests for Down syndrome, cytogenetic and molecular analysis, and dysmorphic fetal features in a pregnancy with 18q-syndrome. A 33-year-old primigravida was referred for genetic counselling because of multiple-marker screen positive results. At 14 weeks' gestation, the woman had a Down syndrome risk of 1:107 calculated from a maternal serum alpha-fetoprotein (MSAFP) level of 1.49 multiples of the median (MOM), a total human chorionic gonadotrophin (hCG) level of 2.42 MOM, and a serum unconjugated oestriol (uE3) level of 0.55 MOM. At 17 weeks' gestation, a repeat test showed a Down syndrome risk of 1:10 calculated from an MSAFP level of 1.09 MOM and a free beta-hCG level of 12.3 MOM. Genetic amniocentesis revealed a de novo deletion of 18q22.2-qter. Intrauterine fetal death occurred at 21 weeks' gestation. At birth, the fetus manifested clinical findings of the 18q-syndrome. The phenotype was correlated with the extent of the deletion. Linkage analysis of the family confirmed the extent and paternal origin of the deletion.
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: C P
authors.initials: CP
authors.lastname: Chen
authors.forename: S R
authors.initials: SR
authors.lastname: Chern
authors.forename: F F
authors.initials: FF
authors.lastname: Liu
authors.forename: S W
authors.initials: SW
authors.lastname: Jan
authors.forename: C C
authors.initials: CC
authors.lastname: Lee
authors.forename: Y C
authors.initials: YC
authors.lastname: Chang
authors.forename: C T
authors.initials: CT
authors.lastname: Yue
mesh_terms: D000328:Adult; D000649:Amniocentesis; D006063:Chorionic Gonadotropin / Q000097:blood; D002872:Chromosome Deletion; D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000235:genetics; D008040:Genetic Linkage; D005819:Genetic Markers; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D007621:Karyotyping; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*
chemical_list: D006063:Chorionic Gonadotropin; D005819:Genetic Markers