Successful pregnancy after preimplantation genetic diagnosis for carrier of t(2;7)(p11.2;q22) with high rates of unbalanced sperm and embryos: a case report

Abstract

Background Regarding the literature on the results of preimplantation genetic diagnosis (PGD) in reciprocal chromosomal translocation carriers seems to prevail a view that this method reduces the frequency of miscarriages, and the pregnancy rate is directly proportional to the number of normal spermatozoa. Therefore, we compared the results of sperm karyotype analysis of a carrier of familial t(2;7)(p11.2;q22) with PGD results. The carrier was ascertained as his wife had had two miscarriages.Methods Empirical data from a pedigree of t(2;7)(p11.2;q22) carrier was collected. A tri-color fluorescence in situ hybridization method (FISH) was used to show the meiotic segregation pattern in sperm of the proband. PGD of blastomeres from a single ICSI cycle and standard prenatal diagnosis procedures to confirm the PGD results was performed.Results Meiotic segregation pattern showed only 34.2% of normal/balanced spermatozoa. The high rate (42%) of miscarriages was observed in this family, which could be explained by chromosomal unbalanced karyotypes as a product of fertilization by unbalanced spermatozoa found with a frequency of approximately 66%. The lack of unbalanced progeny at birth suggests a natural selection of unbalanced fetuses. The 37.5% of normal/balanced embryos received after a single ICSI cycle and PGD was similar to the percentage of normal/balanced spermatozoa (34.2%). After 38 weeks a healthy girl with normal karyotype was born. ConclusionThe presented study is an optimistic message for translocation carriers showing that even in case with more than 60% of genetically unbalanced sperm there is a reasonable chance for reproductive success.

Sperm Nuclear Architecture Is Locally Modified in Presence of a Robertsonian Translocation t(13;17)

“…We did not observe that Robertsonian translocation t(13;17) affects the global nuclear architecture of the pig sperm nucleus (either looking at centromeres, telomeres or gonosomes). The effect of translocations on gonosomes topology described in Wiland et al 2008 [29] may be due to the important rate of unbalanced gametes in sperm from the analyzed infertile patients [54], [55]. We observed a strong impact of the Robertsonian translocation on SSC13 position within the nucleus.…”

Interindividual differences and alterations in the topology of chromosomes in human sperm nuclei of fertile donors and carriers of reciprocal translocations

“…Sperm cells from all carriers were able to fertilize in vivo. The case of T3 was earlier described by Midro et al (2006); T2 was described by Wiland et al (2008), T4 was described by Midro et al (personal communication). For our analysis chromosomes 7, 9, X, and Y were chosen.…”

Reproductive outcome of a case with familial balanced translocation t(3;6): implications for genetic counseling

“…Scriven et al (2013) reported that PGD can reduce the risk of miscarriage to the level found in the general population, and that PGD benefits couples with high-risk translocations. Other studies have reported successful birth after PGD for couples carrying an identical balanced reciprocal translocation (Wiland et al, 2008;Mackie et al, 2010;Beyazyurek et al, 2010). However, there are also risks associated with assisted reproduction treatment.…”