Prenatal diagnosis of a deletion of 18q in a fetus associated with multiple-marker screen positive results.
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.
Chen
C P
CP
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China.
Chern
S R
SR
Liu
F F
FF
Jan
S W
SW
Lee
C C
CC
Chang
Y C
YC
Yue
C T
CT
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*
D006063:Chorionic Gonadotropin; D005819:Genetic Markers