Hong Kong Reproductive Medicine Centre Genetic Testing Projects and Procedures Explained
Hong Kong Reproductive Medicine Centre offers genetic testing capabilities including preimplantation genetic testing (PGT), carrier screening, and chromosome karyotype analysis. This article provides factual knowledge base content covering procedures, suitable candidates, timelines, and precautions, without marketing or promotion.
Direct answer opening (randomly selected module 10)
Yes. Hong Kong Reproductive Medicine Centres generally possess genetic testing capabilities, particularly in preimplantation genetic testing (PGT), with technical levels aligned with international frontiers. However, the specific projects available, applicable conditions, and procedures depend on the centre's qualifications, laboratory configuration, and the patient's medical indications. The following is explained from a clinical practice perspective.
1. What genetic tests can Hong Kong Reproductive Medicine Centres perform?
Currently, medical centres in Hong Kong offering assisted reproductive services primarily cover the following categories of genetic testing:
- Preimplantation Genetic Testing (PGT), including:
- PGT-A (Aneuploidy Screening): Detects abnormalities in the number of embryonic chromosomes, suitable for recurrent miscarriage, repeated implantation failure, advanced maternal age, etc.
- PGT-M (Monogenic Disease Testing): Targets known single-gene genetic disorders (e.g., thalassemia, cystic fibrosis, spinal muscular atrophy).
- PGT-SR (Structural Rearrangement Testing): Suitable for couples carrying balanced chromosomal translocations, Robertsonian translocations, etc.
- Carrier Screening: Blood tests for both partners to detect carrier status for common recessive genetic disease genes, assessing the genetic risk for offspring.
- Chromosome Karyotype Analysis: Analysis of chromosome number and structure from peripheral blood or embryonic cells.
- Y Chromosome Microdeletion Testing: Investigation of male infertility causes.
Some centres also offer expanded carrier screening based on NGS (Next-Generation Sequencing) (e.g., for 300+ diseases), and mitochondrial disease testing (requiring special ethical approval).
2. Why do patients frequently ask about this topic?
Based on practitioner observations, it mainly stems from the following three types of needs:
- Genetic Risk Avoidance: Individuals with a family history of genetic diseases, advanced age (≥35 years), recurrent miscarriage, or adverse pregnancy history hope to reduce the risk of disease in their offspring through genetic testing.
- Trust in Hong Kong Healthcare: Hong Kong's reproductive medicine started early, has strict regulations, and PGT technology is mature. Some mainland Chinese patients actively compare the differences between the two regions.
- Information Asymmetry: Some users mistakenly believe all reproductive centres can perform all genetic tests. In reality, PGT-M and PGT-SR require specific genetic counselling and laboratory conditions, and are not offered by all centres.
3. How do reproductive doctors view the applicability of genetic testing?
Doctor's Decision Logic: Whether to recommend genetic testing primarily depends on medical indications, not patient preference.
- Clear Indications: One or both partners diagnosed with a genetic disease or chromosomal abnormality; repeated implantation failure (≥3 times); ≥38 years old; history of aneuploid pregnancy.
- Not Necessarily Required: For young individuals with normal fertility, no genetic history, and no miscarriage history, PGT-A does not improve live birth rates and may even cause harm due to embryo biopsy.
Doctors will assess indicators such as AMH, antral follicle count, and semen analysis to evaluate whether the number of embryos is sufficient to support biopsy and testing. If the number of retrieved eggs is too low (≤3 mature eggs), the clinical benefit of PGT is often limited.
4. Differences in assisted reproductive genetic testing between Hong Kong and Mainland China
| Comparison Dimension | Hong Kong | Mainland China (some centres) |
|---|---|---|
| PGT Application Regulations | PGT is permitted for genetic diseases and chromosomal abnormalities. No specific age limit, but requires ethics committee approval. | Must comply with "Human Assisted Reproductive Technology Standards". PGT is limited to specific genetic diseases, and only a limited number of centres hold national licenses. |
| Testing Technology Platform | NGS, SNP array, CMA, aCGH are widely used, allowing simultaneous detection of chromosomal copy number variations and single-gene diseases. | Mainstream centres also use NGS, but some still rely on FISH. PGT-M often requires establishing an in-house single-gene testing system. |
| Embryo Biopsy Timing | Often performed on Day 3 (cleavage stage) or Day 5/6 (blastocyst). Blastocyst biopsy has less impact on the embryo. | Primarily blastocyst biopsy, though some centres still perform cleavage-stage biopsy. |
| Carrier Screening | Expanded screening (300+ diseases) is available, with more international result interpretation. | Mostly focuses on a few common genetic diseases (e.g., thalassemia, deafness). Expanded screening is not yet widespread. |
| Average Cost Reference | PGT-A approx. HKD 30,000-50,000; PGT-M approx. HKD 60,000-100,000 (excluding IVF cycle costs). | PGT-A approx. RMB 15,000-30,000, but some centres charge additional genetic counselling fees. |
It is important to note that the speed of ethical review for embryo genetic testing differs significantly between Hong Kong and Mainland China. Complex genetic diseases may require a longer preparation time.
5. Specific process for embryo genetic testing in Hong Kong
- Initial Consultation and Genetic Counselling: Both partners attend together. A genetic counsellor or reproductive doctor assesses family history and previous pregnancy history to determine the necessity and type of testing.
- Family Pedigree Verification (Essential for PGT-M): Blood samples from both partners and known affected family members are collected to construct haplotypes and design testing probes. This step takes approximately 4-8 weeks.
- Standard IVF Cycle: Ovarian stimulation, egg retrieval, in vitro fertilisation, and embryo culture to the blastocyst stage.
- Embryo Biopsy: 3-5 trophectoderm cells are aspirated at the blastocyst stage, and the embryo is vitrified.
- Genetic Testing: The biopsy sample is sent to the laboratory for analysis using NGS or array platforms. PGT-A takes about 2 weeks; PGT-M takes about 3-4 weeks (including probe design time).
- Genetic Counselling Report Interpretation: The doctor or genetic counsellor explains the results, marking euploid embryos or those not carrying the pathogenic gene as suitable for transfer.
- Frozen Embryo Transfer: A normal embryo is selected for thawing and transfer, followed by luteal phase support and pregnancy testing.
6. How long does it take? Timeline reference
| Stage | Estimated Duration |
|---|---|
| Genetic Counselling + Family Pedigree Verification (if needed) | 4-8 weeks (if no prior proband testing has been done) |
| IVF Stimulation, Egg Retrieval, Blastocyst Culture | Approx. 4-6 weeks (depends on individual ovarian response) |
| Blastocyst Biopsy + Vitrification | 1 day (embryo is vitrified immediately after biopsy) |
| Genetic Testing (PGT-A / PGT-M) | 2-4 weeks |
| Report Interpretation + Transfer Preparation | 1-2 weeks |
| Total Cycle (from start to transfer) | Approx. 3-5 months, can be shortened to 2-3 months if family pedigree verification is not required |
The most easily overlooked aspect is the family pedigree verification phase for PGT-M. If proband samples are incomplete or family members are uncooperative, the time may extend to over 3 months.
7. Key testing indicators and clinical significance
- Euploid/Aneuploid: An embryo with 46 chromosomes (23 pairs) is euploid and suitable for transfer. Aneuploidy (e.g., trisomy 21, trisomy 18) increases the risk of miscarriage or birth defects.
- Single-Gene Pathogenic Variants: The PGT-M report indicates whether the embryo carries the same pathogenic mutation as the parents. It is recommended to transfer only embryos not carrying the pathogenic mutation.
- Mosaicism: Some embryos have both normal and abnormal cell lines. If the mosaicism ratio is below 20%, the embryo may still be considered for transfer, but genetic counselling is required.
- Mitochondrial DNA Mutation Load (in rare cases): If there is a high risk of maternal mitochondrial disease, the embryo's mitochondrial mutation load needs to be tested. Only a few centres in Hong Kong have this technology.
Practitioner Observation: Approximately 30% of blastocysts are found to be aneuploid on PGT-A, and this rate increases significantly with female age. The euploidy rate is about 50% for women under 35, and may be less than 25% for those over 40.
8. Typical scenario: Advanced maternal age + recurrent miscarriage
Case Description: Ms. Li (pseudonym), 40 years old, with a history of 2 spontaneous miscarriages (at 8 weeks and 11 weeks of gestation). Both partners have normal chromosome karyotypes and no genetic history. AMH 1.1 ng/mL, antral follicle count 5.
Assessment and Choice:
- PGT-A is suitable because age and miscarriage history indicate a high risk of embryonic aneuploidy.
- PGT-M or PGT-SR are not suitable (no indication).
- Caution: Due to low AMH, the number of retrieved eggs may be limited. The doctor needs to assess whether enough embryos (at least 3-4 blastocysts) can be formed for biopsy. If only 1-2 embryos are available, there may be no normal embryo for transfer after PGT-A.
Process and Timeline: From starting the cycle to transfer, it took about 3 months. Ultimately, 6 eggs were retrieved, forming 4 blastocysts. PGT-A results showed 2 euploid embryos. One was transferred, resulting in a successful pregnancy.
9. Five frequently asked questions from patients
- How accurate is genetic testing in Hong Kong? The accuracy of PGT-A (for determining euploidy/aneuploidy) is over 95%, but false positives and false negatives are possible. Prenatal diagnosis (amniocentesis) is still recommended.
- What materials need to be prepared? ID cards and marriage certificates for both partners, all previous genetic testing reports, miscarriage tissue testing reports (if any), and family genetic disease medical records.
- Are there risks? Embryo biopsy causes minimal damage to the blastocyst but may lead to a slight delay in embryo development or a minor decrease in survival rate after vitrification. In rare cases (<1%), the embryo stops developing after biopsy.
- Is prenatal diagnosis still needed after PGT? Yes. PGT cannot rule out all chromosomal or genetic abnormalities. Chorionic villus sampling or amniocentesis is still recommended during pregnancy.
- What if all embryos are abnormal? Options may include considering egg donation, sperm donation, or embryo donation. This needs to be discussed with the doctor and an ethics consultant.
10. Practitioner observations: Common pitfalls
- Over-reliance on PGT-A: PGT-A does not increase the pregnancy rate per single transfer; it only reduces the risk of miscarriage and birth defects. If the number of embryos is low, it is not advisable to do it blindly.
- Ignoring the timing of genetic counselling: Many patients proceed with IVF first and then consider genetic testing, resulting in no proband sample being collected, making it impossible to design PGT-M probes. It is recommended to undergo genetic counselling before starting IVF.
- Unaware of mutual recognition issues between Hong Kong and Mainland China reports: Some hospitals in Mainland China do not recognise genetic testing reports from Hong Kong and require retesting. If planning to have the transfer in Mainland China, it is best to confirm this first.
- Assuming all centres can perform PGT-M: Currently, only a few large reproductive medicine centres in Hong Kong have the capability to independently design single-gene probes. Most centres need to send samples to partner laboratories (e.g., University of Hong Kong or Chinese University of Hong Kong laboratories).
⚠️ Important Risk Reminder:
- Embryo genetic testing is an invasive procedure. Although the technology is mature, there is still a possibility of embryo damage.
- PGT cannot detect all genetic diseases (e.g., polygenic diseases, de novo mutations), and there may be minor chromosomal abnormalities beyond the scope of testing.
- It is recommended to have at least one face-to-face genetic counselling session before deciding, to fully understand the benefits and limitations.
- Ethical review for embryo genetic testing in Hong Kong is strict. Some diseases require case-by-case approval, and the timeline can be unpredictable.
#PGT-A #PGT-M #BalancedChromosomalTranslocation #BlastocystBiopsy #GeneticCounselling #HongKongIVF #SingleGeneDiseaseScreening #CarrierScreening
This content is sourced from the Reproductive Medicine Knowledge Base, compiled by medical editors for learning reference only and does not constitute medical advice. For specific diagnosis and treatment, please consult a licensed physician.
0 comments