title: Molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 8 or r(8)(::p12→q13.1::) associated with phenotypic abnormalities.
abstract: OBJECTIVE
  We present molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 8.
  
  
  METHODS
  A 35-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+mar[20]/46,XY[39]. However, array comparative genomic hybridization analysis on the subcultured amniocytes revealed no genomic imbalance. Prenatal ultrasound showed bilateral ventriculomegaly, intrauterine growth restriction, and an enlarged right atrium. At 36 weeks of gestation, a 2380-g baby was delivered with mild facial dysmorphism. The baby postnatally manifested right hydronephrosis, vesicoureteral reflux, hypospadias, hypotonia, strabismus, developmental delay and mild mental retardation. Array comparative genomic hybridization and metaphase fluorescence in situ hybridization analyses were performed on the peripheral blood to determine the origin and mosaicism of the sSMC, and quantitative fluorescent polymerase chain reaction was used to exclude uniparental disomy.
  
  
  RESULTS
  The blood had a karyotype of 47,XY,+mar[17]/46,XY[23]. Array comparative genomic hybridization revealed arr 8p12q13.1 (33,476,753-67,428,722)×2.40 (Log2 ratio=0.24) encompassing 98 Online Mendelian Inheritance in Man (OMIM) genes including CHD7, consistent with 30-40% mosaicism for r(8)(::p12→q13.1::). Metaphase fluorescence in situ hybridization identified the sSMC(8) in 21/33 of cultured lymphocytes. Quantitative fluorescent polymerase chain reaction excluded uniparental disomy 8.
  
  
  CONCLUSIONS
  Mosaic sSMC(8) derived from r(8)(::p12→q13.1::) can present phenotypic abnormalities. Chromosome 8q12 duplication syndrome should be included in differential diagnosis when an sSMC(8) contains 8q12.2 and CHD7.
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan. Electronic address: cpc_mmh@yahoo.com.
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chen
authors.affiliation: Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan; Department of Early Childhood Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
authors.forename: Shuan-Pei
authors.initials: SP
authors.lastname: Lin
authors.affiliation: Department of Obstetrics and Gynecology, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan.
authors.forename: Yi-Hui
authors.initials: YH
authors.lastname: Lin
authors.affiliation: Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan.
authors.forename: Schu-Rern
authors.initials: SR
authors.lastname: Chern
authors.affiliation: Gene Biodesign Co. Ltd, Taipei, Taiwan.
authors.forename: Peih-Shan
authors.initials: PS
authors.lastname: Wu
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Yen-Ni
authors.initials: YN
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Shin-Wen
authors.initials: SW
authors.lastname: Chen
authors.affiliation: Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan.
authors.forename: Chien-Wen
authors.initials: CW
authors.lastname: Yang
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Chen
authors.affiliation: Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Bioengineering, Tatung University, Taipei, Taiwan.
authors.forename: Wayseen
authors.initials: W
authors.lastname: Wang
mesh_terms: D000328:Adult; D000649:Amniocentesis; D058674:Chromosome Duplication; D002898:Chromosomes, Human, Pair 8; D055028:Comparative Genomic Hybridization; D019465:Craniofacial Abnormalities / Q000235:genetics*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics; D007621:Karyotyping; D008297:Male; D009030:Mosaicism; D010641:Phenotype; D011247:Pregnancy; D016216:Ultrasonography, Prenatal
chemical_list: D005819:Genetic Markers
keywords: CHD7; chromosome 8q12 duplication syndrome; mosaicism; ring chromosome 8; small supernumerary marker chromosome 8