Preimplantation genetic testing

What is the CEN4GEN Preimplantation genetic testing ?
Preimplantation genetic testing helps doctors and patients identify genetic problems very early within embryos that are created by in vitro fertilization (IVF), before an official pregnancy starts. This benefits high risk couples by lowering the risk or even preventing the transmission of certain known genetic condition(s) to a child prior to implantation of the embryo into the uterine wall of the mother. It could eliminate the dilemma of pregnancy termination often associated with the unfavorable prenatal diagnosis of a genetic medical condition.

CEN4GEN uses a cutting edge molecular genomics based platform to thoroughly analyze the DNA from a single cell isolated from the human blastocyst to test single variants, multiple genes of a panel, as well as a genetic screen of several thousand genes. A negative test result can relieve the patient in knowing that there is a reduced risk of having a child with a genetic disorder(s). A positive test result helps the patient to pursue various reproductive options which may reduce the possibility of having an affected child with a genetic disorder(s). Depending on the nature of the finding, prenatal follow up genetic testing is recommended.

For any standard preimplantation genetic testing request, you must first contact CEN4GEN and provide the following information:

1) specify whether the parents were previously tested (genetic)
2) specify mutation(s) known in the parent(s)
3) specify what genetic disorder (s) is to be investigated

CEN4GEN shall review this information, and let you know whether to proceed with the standard preimplantation genetic testing. Standard preimplantation genetic testing can only proceed on the embryonic material, if one or both parents have already been genetically tested and identified to be carrier of one or more pathogenic or likely pathogenic variant(s). CEN4GEN currently does not offer preimplantation genetic screen or testing for chromosome abnormalities, gene repeat disorders, uniparental disomy, mitochondrial DNA disorders, or methylation disorders.

INDICATION

This test is indicated for:
– Preimplantation carrier testing of the blastocyst for a genetic disorder(s) that is X-linked or Autosomal in etiology.

What are CEN4GEN preimplantation genetic testing options ?
1) CEN4GEN preimplantation medical exome screen (Test code: 800000)
This is a comprehensive exome screening of all coding exons of more than 22000 nuclear genes of the human genome for any known pathogenic or likely pathogenic variants.

2) CEN4GEN preimplantation targeted medical exome screen (Test code: 800001)
This is a comprehensive exome screening of all coding exons of about 5600 disease causing nuclear genes of the human genome for any known pathogenic or likely pathogenic variants.

3) CEN4GEN preimplantation whole nuclear genome screen (Test code: 800002)
This is a comprehensive whole genome screen of the entire nuclear genome for any known pathogenic or likely pathogenic variants.

4) CEN4GEN preimplantation single gene variant test (Test code: 800003)
This test analyzes only a single variant/mutation within a nuclear gene.

5) CEN4GEN preimplantation custom gene panel test (Test code: 800004)
This test analyzes the full coding exons of one or more nuclear genes for any known pathogenic or likely pathogenic variants.

What is the average turnaround time ?
Depending on the type of test ordered, 2 to 5 weeks.

METHODOLOGY

In-solution hybridization of the regions encompassing full exonic gene sequences or whole nuclear genome (when applicable) is performed on the genomic DNA. Direct sequencing of the captured regions is performed using next generation sequencing (NGS). When applicable, bi-directional sanger sequencing is performed on the genomic DNA. The gene sequences are then compared to a standard reference sequence. All sequence variants are evaluated using current scientific data to identify pathogenic and likely pathogenic variants, and carrier status.

DETECTION

Next Generation Sequencing: Clinical Sensitivity: Pathogenic variants in regions other than the targeted area, including the promoter region, some mutations in the introns and other regulatory element mutations, cannot be detected by this analysis. Large deletions/duplications will not be detected by this analysis. This test will not detect chromosome abnormalities, gene repeat disorders, uniparental disomy, mitochondrial DNA disorders or methylation disorders. This test analyzes the nuclear genome.  Results of molecular analysis should be interpreted in the context of the parents’ clinical/biochemical phenotype.

Analytical Sensitivity: ~99%.

Specimen requirements:
At least one blastomere in 1X PBS buffer (excluding calcium and magnesium). Freeze very well, and ship to CEN4GEN on dry ice or on ice pack with overnight delivery.

Or

At least one blastomere in DNAStable Plus reagent. Ship to CEN4GEN at room temperature with overnight delivery.

Contact CEN4GEN for more information at diagnostics@cen4gen.org.