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Karyomapping-a comprehensive means of simultaneous monogenic and cytogenetic PGD: comparison with standard approaches in real time for Marfan syndrome.

Thornhill AR, Handyside AH, Ottolini C, Natesan SA, Taylor J, Sage K, Harton G, Cliffe K, Affara N, Konstantinidis M, Wells D, Griffin DK - J. Assist. Reprod. Genet. (2015)

View Article: PubMed Central - PubMed

Affiliation: School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK.

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Targeted haplotyping by multiplex fluorescent polymerase chain reaction (PCR) of closely linked or intragenic short tandem repeat (STR) markers combined with direct mutation detection improves the accuracy of single cell analysis significantly and minimizes potential errors caused by undetected allele dropout (ADO) or contamination... Mitotic chromosome duplication, which can arise through malsegregation of chromosomes in the cleavage divisions following fertilization, cannot be detected by Karyomapping per se, since the sequence of both chromosomes is identical... However, chromosome duplications may be clinically less significant, since they are often associated with poor morphology and developmental arrest... In the case of PGD for Marfan syndrome, ADO affecting the mutation site on the copy of chromosome 15 carrying the mutation, could cause an affected embryo appear normal (as only the normal allele is successfully amplified)... To reduce the risk of misdiagnosis, a strategy employing a combination of mutation detection and analysis of closely linked short tandem repeat (STRs) was used, revealing the paternal 15q21.1 haplotype associated with the mutation... Following whole genome amplification, targeted haplotyping, with all three STR markers, and direct mutation analysis was successful in 7/8 (87.5 %) of the single cells biopsied from six cleavage stage embryos (Table 2; Fig.  1)... Analysis of the STR alleles present at the FBN 1 locus were consistent with the mutation status in five embryos and identified four as unaffected (Embryos 1, 3–5) and one as affected (Embryo 2)... In the remaining single cell biopsied from Embryo 6 with a normal allele for the mutation, only one of the maternal alleles (200 bp) and neither of the paternal specific alleles (176 and 180 bp) were detected with D15S659... The remaining twin boy was healthy at 2 years... Another of the unaffected embryos (Embryo 1; Table 2), cryopreserved by vitrification at the blastocyst stage on Day 6 post ICSI, was successfully thawed 16 months later and transferred in an unstimulated cycle; no pregnancy resulted... Karyomapping however had the added advantage of not requiring the clinical work-up of a specific test beforehand (only the SNP array information from the parents and an affected child was needed)... Minisequencing in combination with the analysis of several STR markers, yielded results within 24 h for all six embryos in which whole genome amplification of the single cells was successful... In theory, screening for spontaneously arising aneuploidies should increase the likelihood that the embryo chosen for transfer will establish a viable pregnancy and ultimately a healthy child... Indeed, as a selection tool, aneuploidy screening can prioritize the embryo for transfer to achieve improved implantation rates and lower miscarriage rates in fresh transfer cycles as well as support single embryo transfer policy as part of the drive towards reducing multiple birth rates.

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Karyomap of a single blastomere focussing on a region of chromosome 6. The image indicates that there are 11 loci in this region corresponding to disorders currently licensed for PGD by the HFEA. This includes the HLA regions used for diagnoses of saviour siblings
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Fig3: Karyomap of a single blastomere focussing on a region of chromosome 6. The image indicates that there are 11 loci in this region corresponding to disorders currently licensed for PGD by the HFEA. This includes the HLA regions used for diagnoses of saviour siblings

Mentions: Figure 3 illustrates also the flexibility and utility of Karyomapping in that it can in theory be used for multiple loci simultaneously. For instance there are 11 loci corresponding to disorders licensed for PGD by the HFEA (Human Fertilization and Embryology Authority) in the region captured in this figure including the HLA regions which is used for diagnoses involving so called “saviour siblings.”Fig. 3


Karyomapping-a comprehensive means of simultaneous monogenic and cytogenetic PGD: comparison with standard approaches in real time for Marfan syndrome.

Thornhill AR, Handyside AH, Ottolini C, Natesan SA, Taylor J, Sage K, Harton G, Cliffe K, Affara N, Konstantinidis M, Wells D, Griffin DK - J. Assist. Reprod. Genet. (2015)

Karyomap of a single blastomere focussing on a region of chromosome 6. The image indicates that there are 11 loci in this region corresponding to disorders currently licensed for PGD by the HFEA. This includes the HLA regions used for diagnoses of saviour siblings
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4363232&req=5

Fig3: Karyomap of a single blastomere focussing on a region of chromosome 6. The image indicates that there are 11 loci in this region corresponding to disorders currently licensed for PGD by the HFEA. This includes the HLA regions used for diagnoses of saviour siblings
Mentions: Figure 3 illustrates also the flexibility and utility of Karyomapping in that it can in theory be used for multiple loci simultaneously. For instance there are 11 loci corresponding to disorders licensed for PGD by the HFEA (Human Fertilization and Embryology Authority) in the region captured in this figure including the HLA regions which is used for diagnoses involving so called “saviour siblings.”Fig. 3

View Article: PubMed Central - PubMed

Affiliation: School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Targeted haplotyping by multiplex fluorescent polymerase chain reaction (PCR) of closely linked or intragenic short tandem repeat (STR) markers combined with direct mutation detection improves the accuracy of single cell analysis significantly and minimizes potential errors caused by undetected allele dropout (ADO) or contamination... Mitotic chromosome duplication, which can arise through malsegregation of chromosomes in the cleavage divisions following fertilization, cannot be detected by Karyomapping per se, since the sequence of both chromosomes is identical... However, chromosome duplications may be clinically less significant, since they are often associated with poor morphology and developmental arrest... In the case of PGD for Marfan syndrome, ADO affecting the mutation site on the copy of chromosome 15 carrying the mutation, could cause an affected embryo appear normal (as only the normal allele is successfully amplified)... To reduce the risk of misdiagnosis, a strategy employing a combination of mutation detection and analysis of closely linked short tandem repeat (STRs) was used, revealing the paternal 15q21.1 haplotype associated with the mutation... Following whole genome amplification, targeted haplotyping, with all three STR markers, and direct mutation analysis was successful in 7/8 (87.5 %) of the single cells biopsied from six cleavage stage embryos (Table 2; Fig.  1)... Analysis of the STR alleles present at the FBN 1 locus were consistent with the mutation status in five embryos and identified four as unaffected (Embryos 1, 3–5) and one as affected (Embryo 2)... In the remaining single cell biopsied from Embryo 6 with a normal allele for the mutation, only one of the maternal alleles (200 bp) and neither of the paternal specific alleles (176 and 180 bp) were detected with D15S659... The remaining twin boy was healthy at 2 years... Another of the unaffected embryos (Embryo 1; Table 2), cryopreserved by vitrification at the blastocyst stage on Day 6 post ICSI, was successfully thawed 16 months later and transferred in an unstimulated cycle; no pregnancy resulted... Karyomapping however had the added advantage of not requiring the clinical work-up of a specific test beforehand (only the SNP array information from the parents and an affected child was needed)... Minisequencing in combination with the analysis of several STR markers, yielded results within 24 h for all six embryos in which whole genome amplification of the single cells was successful... In theory, screening for spontaneously arising aneuploidies should increase the likelihood that the embryo chosen for transfer will establish a viable pregnancy and ultimately a healthy child... Indeed, as a selection tool, aneuploidy screening can prioritize the embryo for transfer to achieve improved implantation rates and lower miscarriage rates in fresh transfer cycles as well as support single embryo transfer policy as part of the drive towards reducing multiple birth rates.

Show MeSH