Chromosomal segregation of non-human Robertsonian translocations: insights from first genetic experiments – European Journal of Human Genetics

There were 296 couples referred for PGT because either the female (55.1%; 163/296) or the male (44.9%; 133/296) partner was a carrier of the parasite. Table 1 summarizes the translocations tested, the age of the parents at the time of testing, the frequency of use, biopsy re-examination, and the rate of non-resulting tests (due to complete DNA or SNP data without knowledge).

Table 2 summarizes the number of blastocysts analyzed per cycle for rob (13;14), Rob (14;21), and all robs combined. There are fewer blastocysts when the carrier is the mother compared to the father (average 4.60 and 5.49 per IVF cycle, respectively), and the defect is associated with theft (13;14). This does not appear to be a factor in the child’s age; There was no significant difference between the age of female carriers and female carriers (mean age 34.84 years than mean age 34.81 years, P= 0.873.

The division products in the blastocysts are summarized in detail in Table 3. Male carriers can have blastocysts with a chromosomally balanced chromosome complement (another division); The accuracy rate was 84.8% for male carriers and 62.8% for female carriers.P0.00001). A restricted subset analysis of theft (13;14) and theft (14;21) showed a higher number of correct products for male carriers for each of the common types of theft.

Table 3 also shows the breakdown of monosomy versus trisomy and the divisions are interpreted as side by side. For all carriers combined, the proportion of blastocysts with monosomy was significantly lower for male carriers (60/152, 39.5%) than for female carriers (218/396, 55.1%) (test for two independent groups they, P= 0.001). However, this difference depends on the specific type of theft. For theft (13;14), the same pattern was found; Less monosomy for chromosomes 13 or 14 was observed for male carriers (36/103, 35.0%) compared to monosomy for chromosomes 13 or 14 for female carriers (140/251, 55.8 %)P= 0.0004). For male carriers (14;21), no such difference was evident with monosomy of chromosome 14 or 21 for male carriers (12/24, 50%) with monosomy of chromosome 14 or was 21 for female carriers (50/93, 53.8%) (P= 0.74).

There was also evidence for non-self segregation products for 21 blastocysts with chromosome complements corresponding to 3:0 segregation (16 with double trisomy and 5 with double monosomy). For maternal carriers, 16 cases showed a 3:0 split including double trisomy and one case showed double monosomy. In contrast, double trisomy was not observed for paternal carriers, but quadruple monosomies were detected (Fisher’s test, P0.05).

In six blastocysts (0.7%), there is a combination of trisomy and monosomy that does not correspond to the product of division eight that can arise during the division of theft. We refer to these as “noncanonical”. Six are the products of maternal carriers, with five related to steal (13;14) with trisomy 13 and monosomy 14, and one related to rob (14;21) with trisomy 14 and monosomy 21. There is only one cases of UPD (heterodisomy) found in our dataset. This case involves a man who is a thief (15;21) with arr [15]x2 htz mat blastocyst sample.

In order to provide robust data for genetic counseling for individuals with extortion (13;14) and theft (14;21), we combined our findings on the probability of correct separation with judgments from the literature. two more recently (Table 4). We then calculated the probability of at least one normal blastocyst using the binomial equation, under the assumption that each embryo was completely independent of others from the same patient. These observations show that for an average reference with four or six blastocysts available (Table 2), PGT should increase the chance of being able to select for the right embryo. These calculations do not include abnormal chromosomes that have nothing to do with the theft.

To determine the possible relationship between the age of the carriers and the classification criteria, the data for the female and male carriers were analyzed separately, combining the data in the 3-year period. Figure 1A shows that there is no difference in the rate of nonsignificant odds for maternal carriers across different maternal ages (Armitage-Cochran test, P= 0.58, slope = 0.006). Since maternal and paternal age were correlated, it was expected and observed that no age association was observed for paternal age (P= 0.23, slope = 0.014) (Fig. 1B). To obtain more evidence of a maternal age effect, we considered only 3:0 splits from female carriers. For 17 cases (sixteen series) and 3:0 separation of blastocysts from female carriers, the age of the mother at the time of the test was 34.6 years compared to 34.8 years for female carriers and separation type others (Mann-Whitney test, P= 0.624).

x-axis, age group; the y-axis ratio (%) has an irregular distribution. A Mother’s age for female carriers. B Father’s year for mothers. C Mother’s age for men. d Father’s year for men. The vertical line indicates the 95% confidence interval.

For paternal carriers, there was a continuous trend in the lower number of non-paired divisions with increasing parental age (Fig. 1C, D). For father’s age, this did not reach statistical significance (P= 0.052, slope -0.017) but for maternal age, a stronger trend was observed (P= 0.0035, slope -0.026) which is significantly different from linearity and shows that it may be a non-linear relationship.

To find out whether the genetic factors are associated with an increase in other chromosomal abnormalities (interchromosomal effects) [10, 21]or a decrease in level due to a decrease in the ability of embryos with multiple chromosome imbalances, we considered the number of abnormal chromosomes (that is, unrelated to theft). When the embryo has an abnormality, the abnormality rate is sometimes 38.7%. For those embryos that were suitable or appropriate for the chromosomes to be stolen, the number of occasional abnormalities was 42.8%. The difference between the two rates did not reach statistical significance (P= 0.086. For the age-matched control group of mothers (excluding those who provide diapers) who were not carriers, the rate of occasional abnormalities was 44.1%. These data do not fully exclude interchromosmal effects related to specific chromosomes (for example, acrocentrics are not involved in translocation).