SNP array embryo genetic testing

New hope for couples wanting to become parents – SNP array embryo genetic testing

Couples who have experienced the heartbreak of miscarriage or the disappointment of numerous failed IVF cycles are among those now being offered new hope of realising their dream of having a healthy baby.

Leading Australian infertility treatment provider Monash IVF is offering “at risk” couples the chance to access the latest form of preimplantation genetic screening (PGS) that includes a full chromosome count of embryos to ensure only the healthiest are implanted.

Monash IVF geneticist and PGS coordinator, Dr Elissa Osborne, explained that PGS is available to couples at risk of passing on a chromosome abnormality or a specific genetic disease to their children.

She said the test could be useful for older women, couples who have suffered multiple miscarriages, couples who have experienced repeat IVF failure, as well as those who know they have a specific gene disorder such as cystic fibrosis in the family.

Through testing, embryos can be screened for a range of genetic conditions including Down Syndrome, Huntington’s disease and Spinal Muscular Atrophy before pregnancy is established, Dr Osborne said.

“Until the development of array testing, PGS tests could only analyse several genetic sites at a time, therefore limiting the diagnostic capability of PGS,’’ Dr Osborne said. SNP (single nucleotide polymorphism) arrays represent a further advancement in genetic testing of IVF embryos.

SNP array testing is performed on cells that have been sampled from an IVF embryo that is 5 or 6 days old. The testing involves analysis of more than 300,000 different DNA sites within those cells. A blood sample is taken from each parent and is screened in parallel with the cells from the embryo.

By using parent DNA as reference data to compare to the embryonic DNA, it is possible to produce results that are far more precise than conventional testing methods.

“The breakthrough with the latest SNP array testing is that in addition to screening all 23 chromosome pairs, it detects a far wider range of chromosome abnormalities and can determine the genetic source of any additional or missing chromosomes. It can also detect whether these abnormalities occurred before or after fertilisation.

“With the old testing we couldn’t tell whether the chromosome abnormality came from the egg or the sperm. Now that we have this information through SNP array testing couples can make informed decisions and potentially consider whether they want to use donor eggs or donor sperm,’’ Dr Osborne said.

“We’re very excited to be the only provider in Australia offering this test and there’s a lot of interest among the scientific community as well as couples looking at IVF.’’

The process is capable of screening all 23 pairs of chromosomes with results that are typically more than 99 percent accurate. Other PGS methods that miss certain types of chromosome problems or that only test some of the chromosomes, are at risk of missing important genetic information.

“Each embryo is precious and accuracy is critical to avoid discarding normal embryos or transferring abnormal embryos,’’ Dr Obsorne said.

If you would like further information about this testing please complete our online enquiry form or call 1800 628 533.

 

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