title: Blood chimerism in a girl with Down syndrome and possible freemartin effect leading to aplasia of the Müllerian derivatives.
abstract: Cytogenetic and molecular genetic analysis in a case of sex-discordant dizygotic twins revealed blood chimerism in the girl (46,XY in blood and 47,XX, + 21 in fibroblasts) caused by feto-fetal transfusion from her healthy brother. The girl presented with Down syndrome, aplasia of the uterus and the Fallopian tubes and normal female external genitalia. We propose that the lack of Müllerian structures is caused by the effect of the Müllerian inhibiting substance transferred from the male to the female twin in early pregnancy. This disorder of sex development is known as freemartin phenomenon in female cattle from sex-discordant twin pairs.
authors.affiliation: Institute of Human Genetics, ZMBE Westfalian Wilhelms-University of Münster and University Clinics Münster, Münster, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Bogdanova
authors.forename: U
authors.initials: U
authors.lastname: Siebers
authors.forename: R
authors.initials: R
authors.lastname: Kelsch
authors.forename: A
authors.initials: A
authors.lastname: Markoff
authors.forename: A
authors.initials: A
authors.lastname: Röpke
authors.forename: R
authors.initials: R
authors.lastname: Exeler
authors.forename: J
authors.initials: J
authors.lastname: Tsokas
authors.forename: P
authors.initials: P
authors.lastname: Wieacker
mesh_terms: D000328:Adult; D000818:Animals; D002417:Cattle; D002675:Child, Preschool; D002678:Chimera / Q000235:genetics*; D041322:Chromosomes, Human, Y; D004314:Down Syndrome / Q000097:blood / Q000235:genetics* / Q000276:immunology; D005260:Female; D005330:Fetofetal Transfusion / Q000097:blood / Q000235:genetics; D005611:Freemartinism / Q000235:genetics*; D006239:Haplotypes; D006650:Histocompatibility Testing; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping; D008214:Lymphocytes / Q000648:ultrastructure; D008297:Male; D009095:Mullerian Ducts / Q000002:abnormalities*; D010375:Pedigree; D011247:Pregnancy; D014429:Twins, Dizygotic