title: Prenatal diagnosis and genetic analysis of a fetus with 47,XX,+21/46,XX mosaicism and XX/XY chimerism.
abstract: Prenatal diagnosis of simultaneous occurrence of chimerism and autosomal mosaicism is extremely rare. We report the prenatal diagnosis and genetic analysis of a fetus in a twin pregnancy with mosaic 47,XX,+21/46,XX with chimeric XX/XY. A 36-year-old, para 1, woman was referred for genetic counseling at 20 weeks' gestation because of abnormal karyotype (47,XX,+21/46,XX) in one fetus in a twin pregnancy. Cordocentesis revealed 47,XX,+21[3]/46,XX[35]/46,XY[7] in this fetus. Postnatal cytogenetic analysis of cord blood confirmed three cell lines in this twin (A) and 46,XY in the co-twin (B). Postmortem pathologic findings of both fetuses were normal. Fluorescence in situ hybridization identified three cell lines in the cord blood of twin A. Molecular genetic analysis using polymorphic DNA markers revealed parental origin of fetal tissue, and confirmed the chimeric status. Molecular genetic analysis with polymorphic DNA markers help to differentiate chimerism from mosaicism and define the origin of cell lines, which may have importance in genetic counseling.
authors.affiliation: Department of Obstetrics and Gynecology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. hwahl013@ms10.hinet.net
authors.forename: Hsiao-Lin
authors.initials: HL
authors.lastname: Hwa
authors.forename: Tsang-Ming
authors.initials: TM
authors.lastname: Ko
authors.forename: Chien-Hao
authors.initials: CH
authors.lastname: Huang
authors.forename: Li-Shu
authors.initials: LS
authors.lastname: Chang
mesh_terms: D000328:Adult; D046528:Chimerism; D004200:Diseases in Twins; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009030:Mosaicism; D011296:Prenatal Diagnosis
chemical_list: D005819:Genetic Markers