title: Prenatal detection and characterization of a psu idic(8)(p23.3) which likely derived from nonallelic homologous recombination between two MYOM2-repeats.
abstract: Mosaicism with an isodicentric 8 with a breakpoint at p23.3 [idic(8)(p23.3)] is very rare. We report the first prenatal case on a male fetus, in which obstetric ultrasound revealed multiple congenital anomalies at 28 weeks of gestation. Cytogenetic analysis of amniocytes showed mos 45,XY,-8,psu idic(8)(p23.3)[16]/46,XY,psu idic(8)(p23.3)[4], and that of cord blood lymphocytes revealed mos 46,XY, psu idic(8)(p23.3)[37]/45,XY,-8,psu idic(8)(p23.3)[13]. Fluorescence in situ hybridization studies revealed that the break-reunion occurred at the cytoband 8p23.3 within the physical position 2.08 Mb from the 8p telomere. Chromosomal microarray analyses further assigned the duplication/deletion breakpoint at 2.16 Mb (Agilent 244K) and at 2.19 Mb (Affymetrix SNP6.0). Analysis of microsatellite DNA indicated that the psu idic(8)(p23.3) was derived from the maternal chromosome 8. Together, these findings indicate that the fetus was nullisomic for ~2.2 Mb from 8pter, trisomic for the rest of chromosome 8 in mosaic condition, and likely had breaks in MYOM2 repeats of the maternal chromosome 8.
authors.affiliation: Departments of Biomedical Sciences and Medical Research, Chung Shan Medical University and Hospital, Taichung, Taiwan.
authors.forename: Yueh-Chun
authors.initials: YC
authors.lastname: Li
authors.affiliation: Departments of Obstetrics and Gynecology, China Medical University and Hospital, Taichung, Taiwan; Department of Medical Genetics, China Medical University and Hospital, Taichung, Taiwan.
authors.forename: Shu-Chin
authors.initials: SC
authors.lastname: Chien
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.
authors.forename: Sunita R
authors.initials: SR
authors.lastname: Setlur
authors.affiliation: Department of Medical Genetics, China Medical University and Hospital, Taichung, Taiwan.
authors.forename: Wei-De
authors.initials: WD
authors.lastname: Lin
authors.affiliation: Department of Medical Genetics, China Medical University and Hospital, Taichung, Taiwan.
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.affiliation: Department of Medical Research, China Medical University and Hospital, Taichung, Taiwan; Graduate Institute of Basic Medical Sciences, China Medical University and Hospital, Taichung, Taiwan. Electronic address: lincc@mail.cmu.edu.tw.
authors.forename: Chyi-Chyang
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis*; D000328:Adult; D002898:Chromosomes, Human, Pair 8; D020732:Cytogenetic Analysis; D005260:Female; D005865:Gestational Age; D059765:Homologous Recombination / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008279:Magnetic Resonance Imaging; D009030:Mosaicism; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014314:Trisomy / Q000175:diagnosis*; D024182:Uniparental Disomy / Q000175:diagnosis*
keywords: dicentric chromosome 8p; non-allelic recombination; prenatal diagnosis; segmental duplication