Single gene disease is a hereditary disease caused by a mutant allele of a single gene, e.g. alpha or beta-thalassemia, spinal muscular atrophy, duchenne muscular dystrophy, cystic fibrosis, etc.
How I can undergo PGD for single gene disorder to avoid the affected child?
- Couples who are at risk to have child with single gene disease are mostly not infertile. Before undergoing PGD-single gene disorder, investigation for disease-causing mutation, genetic and IVF counseling are mandatory for specific-PGD lab setup.
- Ovarian stimulation, egg retrieval and sperm collection, ICSI will be done. The embryo will be cultured to reach the blastocyst stage on the fifth and sixth day of development. Three to five trophectoderm cells, that will be destined to be the placenta, are removed and analyzed for genetic evaluation. In case of day 3 biopsy, 2 blastmeres will be removed for PGD-single gene disease. The biopsied embryos will be frozen immediately after biopsy.
- After extraction and amplification of the DNAs from sample cells, the amount of DNAs is increased by polymerase chain reaction technique (PCR). The specific part of amplified DNA samples will be checked with pre-set up PGD-lab to identify the mutant DNAs.
- The unaffected embryos will be transferred to the womb in the frozen-thawed cycle.
Is the result of PGD-single gene disorder reliable?
The reliability of the test is 95%. However, prenatal diagnosis for such disease is strongly recommended.
Risk of the PGD-single gene disease
- The results can be achieved in 95% of the tested embryos.
- 10-15% of the PGD cycles end up with no suitable embryos for transfer : all embryos carries the mutant genes or embryos without mutant genes may have other unrelated chromosomal errors.
- Risk of the IVF and biopsy process : please refer to patient information and overview for PGD