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Isodicentric Y Chromosome with Multiple Breakpoints in the Pseudoautosomal Region 1
Yasuko Ogiwara1,2, Yoshitomo Kobori3, Erina Suzuki1
1Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan.
Cytogenetic and Genome Research
|July 29, 2024
Summary
This study investigates the formation of isodicentric Y chromosomes [idic(Yq)] with breakpoints in the pseudoautosomal region 1 (PAR1). Findings suggest multiple DNA breaks in PAR1 facilitated by its chromatin structure caused this Y chromosome rearrangement.
Area of Science:
- Human genetics
- Genomics
- Molecular biology
Background:
- Isodicentric Y chromosomes are common structural genomic variants.
- The formation mechanism of isodicentric Y chromosomes with short arm breakpoints [idic(Yq)] is not fully understood.
Observation:
- A case study of a Japanese man with azoospermia and short stature revealed a 45,X/46,X,idic(Y)(qter→p11.32::p11.32→qter) karyotype with a terminal deletion.
- Whole-genome sequencing identified four breakpoints within a 7 kb region of pseudoautosomal region 1 (PAR1) on the Y chromosome.
Findings:
- The idic(Yq) in this patient likely resulted from multiple DNA double-strand breaks within PAR1.
- The specific chromatin structure of PAR1 may have promoted this Y chromosome rearrangement.
Implications:
- Clinical features, including azoospermia and short stature, are attributed to SHOX gene haploinsufficiency and the 45,X cell line.
- Y chromosome gene copy-number gains and PAR1 size reduction may also contribute to spermatogenic failure.
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