title: Prenatal diagnosis of a rare inherited heterochromatic variant chromosome 4.
abstract: Heterochromatic chromosome polymorphisms have been extensively reported. Most are associated with C-band positive regions located on chromosomes 1, 9, 16, and Y. We report a prenatal case of a rare heterochromatic variant on chromosome 4. Amniocentesis was performed on a 35-year-old white female for AMA. The karyotype was 46,XY,add(4)(q35)?. One chromosome 4 homolog had an additional dark band at the terminus of the long arm. Parental chromosome analyses revealed that the chromosome 4 was maternally inherited. The mother and fetus were both Q and C-band positive and NOR and DAPI Distamycin staining negative. FISH using Y, 4, and 9 whole chromosome paint (WCP), centromere probes for all chromosomes (Cytocell, Chromoprobe Multiprobe-I System, Rainbow Scientific, Inc., Windsor, CT), alpha-satellite probes for 13/21, 14/22 (D13Z1/D21Z1; D14Z1/D22Z1, Oncor, Gaithersburg, MD), and the 15 PWS/Angelman probe (LSI SNRPN, D15Z1, PML, Vysis, Inc., Downers Grove, IL) were negative. The TelVysion 4q telomere probe (D4S2930, Vysis, Inc.) was positive. A phenotypically normal male was born at 37 weeks. Follow up studies on placenta, cord, cord blood, and foreskin confirmed the prenatal results. Based on these findings, it appears that this chromosome 4 was a rare heterochromatic variant. Heterochromatic variants have been demonstrated to have no phenotypic effect on carriers. This case illustrates the importance of reporting unusual variant chromosomes for genetic counseling purposes. To the best of our knowledge, this is the first report of a heterochromatic variant involving part of the long arm of chromosome 4 in a phenotypically normal mother and child.
authors.affiliation: Department of Laboratory Medicine, Long Island Jewish Medical Center, The Long Island Campus of The Albert Einstein College of Medicine, New Hyde Park, New York 11040, USA. azaslav@lij.edu
authors.forename: Ann-Leslie
authors.initials: AL
authors.lastname: Zaslav
authors.forename: Guy
authors.initials: G
authors.lastname: Pierno
authors.forename: Arthur
authors.initials: A
authors.lastname: Fougner
authors.forename: Jessy
authors.initials: J
authors.lastname: Jacob
authors.forename: Geraldine
authors.initials: G
authors.lastname: Shikora
authors.forename: Rehana
authors.initials: R
authors.lastname: Kazi
authors.forename: Donna
authors.initials: D
authors.lastname: Blumenthal
authors.forename: Fakhry
authors.initials: F
authors.lastname: Alexander
authors.forename: Joyce E
authors.initials: JE
authors.lastname: Fox
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000166:cytology; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D005260:Female; D006570:Heterochromatin / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping; D010920:Placenta / Q000166:cytology; D011247:Pregnancy; D011296:Prenatal Diagnosis
chemical_list: D006570:Heterochromatin