Long-term follow-up of females with unbalanced X;Y translocations-reproductive and nonreproductive consequences

Duplication of Yq- and proximal Yp-arms with deletion of almost all PAR1 (including SHOX) in a young man with non-obstructive azoospermia, short stature and skeletal defects

Duplications of Yq arm (and AZF) seems to be tolerated by fertile males, while mutations, deletions, duplications or haploinsufficiency of SHOX can originate a wide range of phenotypes, including short stature and skeletal abnormalities. We report a case of non-obstructive azoospermia in a young man with short stature, skeletal anomalies, normal intelligence and hormonal parameters. This male showed a very singular Y-chromosome aberration, consisting of a duplication of Yq and proximal regions of Yp, with a deletion of almost all PAR1 in Yptel, including SHOX. CBA- and RBA-banding and FISH-mapping with telomeric, centromeric, AZF and SHOX probes were used. These results were confirmed by array CGH, which revealed the following karyotype constitution: arr [hg19] Xp22.33 or Yp11.32p11.31 (310,932-2,646,815 or 260,932-2,596,815) ×1, Yp11.2q12 (8,641,183-59,335,913) ×2. We conclude that the haploinsufficience of SHOX may be the cause of short stature and skeletal defects in the patient, while the non-obstructive azoospermia could be related to the lack of X-Y pairing during meiosis originated by the anomalous configuration of this chromosome abnormality and large deletion which occurred in Yp-PAR1.

A balanced chromosomal translocation involving chromosomes 3 and 16 in a patient with Mayer-Rokitansky-Kuster-Hauser syndrome reveals new candidate genes at 3p22.3 and 16p13.3

BACKGROUND

Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome, or the congenital absence of uterus and vagina, is the most severe anomaly of the female reproductive tract. It affects 1 in 5,000 females, and is the second most common cause of primary amenorrhea. The etiology remains unknown in most patients, although four single gene defects and some repetitive copy number variants (CNVs) have been identified. Translocations in MRKH patients are very rare, and reported only in three patients previously without breakpoint mapping. We have identified the fourth MRKH translocation patient and are the first to characterize the breakpoints mapped by molecular methods.

RESULTS

The proband is a 17- year old white female with agenesis of the uterus and vagina who had a peripheral blood karyotype revealing a de novo balanced translocation 46,XX,t(3;16)(p22.3;p13.3)dn. There were no known related anomalies present in the proband or her family. No CNVs were found by chromosomal microarray analysis, and no genes were directly disrupted by the translocation. DNA sequencing of six nearby candidate genes-TRIM71, CNOT10, ZNF200, OR1F1, ZNF205, and ZNF213-did not reveal any mutations. RT-qPCR of proband lymphoblast RNA for 20 genes near the breakpoints of 3p22.3 and 16p13.3 showed significantly altered expression levels for four genes in the proband compared to three white female controls, after correction for multiple comparisons. Reduced expression was seen for CMTM7 and CCR4 on 3p22.3, while increased expression was observed for IL32 and MEFV on 16p13.3.

CONCLUSION

We have mapped the breakpoints of our t(3;16)(p22.3;p13.3) translocation patient using molecular methods to within 13.6 kb at 3p22.3 and within 1.9 kb for 16p13.3 and have suggested 10 nearby genes that become plausible candidate genes for future study.