title: Dicentric chromosome 13 and centromere inactivation.
abstract: The karyotype of a child with dysmorphic findings suggestive of both trisomy 13 and the 13q--syndrome was found to have cells with one of two different dicentric chromosomes: one bearing a duplication of chromosome 13q [46,XX,-13, + psu dic (13)t(13;13)(pter leads to cen leads to q34::q34 leads to pter)] and the other a deletion of 13q [46,XX,-13, + psu dic (13)t(13;13)(pter leads to cen leads to q22::q11 leads to pter]. Longitudinal cytogenetic studies in leukocytes demonstrated a loss of those cells possessing the small dicentric [psu dic(13)(q22;q11)], whereas fibroblasts from two separate skin biopsies contained only this marker. Q-band polymorphisms indicated that both dicentrics were of paternal origin, with the smaller dicentric derived from the larger via the bridge-breakage-fusion cycle. The presence of two active centromeres could not be confirmed in either dicentric.
mesh_terms: D002503:Centromere / Q000502:physiology*; D002869:Chromosome Aberrations / Q000235:genetics*; D002871:Chromosome Banding; D002872:Chromosome Deletion; D025063:Chromosome Disorders; D002875:Chromosomes / Q000502:physiology*; D002901:Chromosomes, Human, 13-15 / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008938:Mitosis; D014314:Trisomy