Kawamura R, Inagaki H, Yamada M, Suzuki F, Naru Y, Kurahashi H. A Turner syndrome case associated with dic(Y;22).
Mol Cytogenet 2021;
14:34. [PMID:
34238329 PMCID:
PMC8264959 DOI:
10.1186/s13039-021-00556-z]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/29/2021] [Indexed: 11/25/2022] Open
Abstract
Background
Constitutional telomeric associations are very rare events and the mechanism underlying their development is not well understood.
Case presentation
We here describe a female case of Turner syndrome with a 45,X,add(22)(p11.2)[25]/45,X[5]. We reconfirmed this karyotype by FISH analysis as 45,X,dic(Y;22)(p11.3;p11.2)[28]/45,X[2].ish dic(Y;22)(SRY+,DYZ1+). A possible mechanism underlying this mosaicism was a loss of dic(Y;22) followed by a monosomy rescue of chromosome 22. However, SNP microarray analysis revealed no loss of heterozygosity (LOH) in chromosome 22, although a mosaic pattern of LOH was clearly detectable at the pseudoautosomal regions of the sex chromosomes.
Conclusions
Our results suggest that the separation of the dicentric chromosome at the junction resulted in a loss of chromosome Y without a loss of chromosome 22, leading to this patient’s unique mosaicism. Although telomere signals were not detected by FISH at the junction, it is likely that the original dic(Y;22) chromosome was generated by unstable telomeric associations. We propose a novel “pulled apart” mechanism as the process underlying this mosaicism.
Supplementary Information
The online version contains supplementary material available at 10.1186/s13039-021-00556-z.
Collapse