title: A dispermic chimerism in a 2-year-old Caucasian boy.
abstract: Detection of two different cell populations in a child is a rare event. The following case of a dispermic chimera was diagnosed before surgery due to problems in blood group determination. A 2-year-old phenotypically male child was admitted for correction of a penoscrotal hypospadia and unilateral cryptorchism. During presurgical laboratory investigation, difficulties in blood group determination occurred. Blood group typing was performed by the DiaMed-ID Micro Typing System and by FACS. Additionally, cytogenetic analysis of lymphocytes and analysis of DNA polymorphisms in different tissues were performed. Two populations of red blood cells were detected, O cells accounting for 75% and B cells for 25%. Analysis of DNA-PCR polymorphisms in lymphocytes, nails, and in cells of the oral mucous membrane demonstrated a chimerism, with two alleles inherited from the father and one from the mother. A cytogenetic analysis of cultured lymphocytes showed a mosaic 46, XY/46,XX. Surgery revealed a prostatic utricle grade III, also called pseudovagina; genitography confirmed a vagina. Bilateral gonad biopsy showed a testis on one side and an ovary on the other. This case of chimerism represents a true hermaphroditism that most probably developed by double fertilization of one or more egg nuclei by two sperms.
authors.affiliation: Department of Pediatrics, University Hospital of Göttingen, Robert-Koch-Strasse 40, D-37075 Göttingen, Germany. ahumpe@med.uni-goettingen.de
authors.forename: L M
authors.initials: LM
authors.lastname: Repas-Humpe
authors.forename: A
authors.initials: A
authors.lastname: Humpe
authors.forename: R
authors.initials: R
authors.lastname: Lynen
authors.forename: B
authors.initials: B
authors.lastname: Glock
authors.forename: E M
authors.initials: EM
authors.lastname: Dauber
authors.forename: G
authors.initials: G
authors.lastname: Simson
authors.forename: W R
authors.initials: WR
authors.lastname: Mayr
authors.forename: M
authors.initials: M
authors.lastname: Köhler
authors.forename: S
authors.initials: S
authors.lastname: Eber
mesh_terms: D001788:Blood Grouping and Crossmatching; D002675:Child, Preschool; D002678:Chimera; D012734:Disorders of Sex Development / Q000235:genetics*; D005837:Genitalia, Male / Q000002:abnormalities; D006801:Humans; D008297:Male; D010641:Phenotype