Prenatal diagnosis and genetic analysis of X chromosome polysomy 49, XXXXY.
We report on the prenatal diagnosis, genetic analysis and clinical manifestations of a 49,XXXXY fetus. A 31-year-old, primigravida woman was referred for genetic counselling at 17 weeks' gestation with the sonographic findings of intrauterine growth retardation, generalized oedema, a large septated cystic hygroma colli measuring 5x4 cm, and abnormal posturing of the lower extremities. Quantitative fluorescent polymerase chain reaction (QF-PCR) with small tandem repeat (STR) markers specific for chromosome X and a pentanucleotide marker X22 for the Xq/Yq pseudoautosomal region PAR2 rapidly detected the X-chromosome polysomy from amniotic fluid cells. This abnormality appeared to arise from successive non-disjunction during maternal meiosis I and meiosis II. Cytogenetic analysis revealed a karyotype of 49,XXXXY. Our case shows that a 49,XXXXY fetus in the second trimester may demonstrate hydrops fetalis and a large septated cystic hygroma colli by prenatal ultrasound. Our case also shows that QF-PCR assays with sex chromosome specific STR markers provide rapid prenatal diagnosis of numerical sex chromosome aneuploidy as well as its genetic cause in fetal cystic hygroma.
Chen
C P
CP
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China. cpc_mmh@yahoo.com
Chern
S R
SR
Chang
C L
CL
Lee
C C
CC
Chen
W L
WL
Chen
L F
LF
Wang
W
W
D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging / Q000235:genetics*; D000025:Abortion, Eugenic; D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry; D000782:Aneuploidy; D004247:DNA / Q000032:analysis; D005260:Female; D005819:Genetic Markers; D006801:Humans; D007621:Karyotyping; D018191:Lymphangioma, Cystic / Q000000981:diagnostic imaging / Q000235:genetics*; D008297:Male; D018895:Microsatellite Repeats; D009630:Nondisjunction, Genetic; D016133:Polymerase Chain Reaction; D011247:Pregnancy / Q000097:blood; D011262:Pregnancy Trimester, Second; D012729:Sex Chromosome Aberrations / Q000000981:diagnostic imaging / Q000235:genetics*; D016216:Ultrasonography, Prenatal; D014960:X Chromosome / Q000235:genetics*
D005819:Genetic Markers; D004247:DNA