Prenatal Diagnosis

Introduction

Prenatal diagnosis is the process of evaluating the presence of disease or potential disease in the fetus. This enables families to be better prepared before the birth of the baby.

The Prenatal Diagnostic & Counselling Service including Mrs. Wu Chung Prenatal Diagnostic Laboratory was established at Tsan Yuk Hospital in 1981.

The Prenatal Diagnostic & Counselling team accepts referrals for prepregnancy counselling, pre-implantation genetic diagnosis, prenatal diagnosis, counselling & therapy, and provides prenatal screening and diagnosis of chromosomal disorders, metabolic and genetic disorders and fetal anomalies.

Clinical Services

  • Prenatal Screening for thalassaemia, Down syndrome, and structural abnormalities

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    • Antenatal screening for thalassaemia
    • Nuchal translucency for fetal Down syndrome screening in multiple pregnancy
    • First trimester combined, integrated, or second trimester serum screening for fetal Down syndrome
    • 19 to 21 week fetal morphology scan
  • Non-invasive and invasive prenatal diagnosis

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    • Targeted 2D ultrasound examination in 1st and 2nd trimester
    • Fetal echocardiography (joint consultation with paediatric cardiologist)
    • 3D/4D ultrasound examination
    • Noninvasive ultrasound diagnosis of a-thalassaemia
    • Invasive diagnostic procedures including amniocentesis, chorionic villus sampling, cordocentesis, embryoscopy, hysterofetoscopy
  • Medical and surgical fetal therapy

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    • Various shunting procedures for fetal disorders such as urethral obstruction or pleural effusion
    • Laser photocoagulation for twin abnormalities such as severe twin-twin transfusion syndrome
    • In-utero transfusion for treatment of fetal anaemia
    • Amnio-reduction
    • Medical treatment for cardiac arrhythmia
    • Radiofrequency ablation for complicated multiple pregnancies
  • Fetal monitoring for high risk pregnancies

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    • Multiple pregnancies
    • Intrauterine growth restriction
    • Fetal abnormalities
    • Rhesus isoimmunisation
  • Multidisciplinary genetic counseling

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    • Joint counseling for fetal anomalies with clinical geneticists, paediatricians or paediatric surgeons
    • Prepregnancy counselling
    • Pre-implantation genetic diagnosis
    • Pregnancy following preimplantation genetic diagnosis

Laboratory Services

History of Prenatal Diagnostic Laboratory

The Mrs. Wu Chung Prenatal Diagnostic Laboratory was established by the Department of Obstetrics and Gynaecology of the University of Hong Kong in 1981. The capital cost of the laboratory was paid by the Hong Kong Government and by a donation from Mrs. Wu Chung. The operation cost was paid by the Hong Kong Government until December 1991 and then by the Hospital Authority who came over the management of all the government hospitals in December 1991. Staff members of the laboratory are employed by the Hospital Authority and the University of Hong Kong. The laboratory is providing prenatal diagnostic and screening laboratory service in Hong Kong. The laboratory is accredited by HOKLAS (ISO 15189, International Organisation for Standardization (ISO) standard for medical laboratories) with scope of tests as specified in HOKLAS Directory of Accredited Laboratories.

Information on requesting Cytogenetic, Molecular, Thalassaemia, Down
Syndrome Screening Tests and Reproductive Medicine Investigations

Cytogenetic study (Karyotypes) Instructions to doctors on sending samples Download PDF Download PDF
Rapid Aneuploidy Detection
(Chr 13, 18, 21, XY)
Request form (for HA / Private) Download PDF Download PDF
22q11.2 microdeletion
Thalassaemia genetic testing Instructions to doctors on sending samples for Thalassaemia genetic testing Download PDF Download PDF
Thalassaemia Screen Request (for HA/Private) Download PDF
+ Request form (for HA / Private) Download PDF Download PDF
Reproductive medicine investigations Instructions to doctors on sending samples for reproductive medicine investigations Download PDF Download PDF
Request form for Laboratory Studies (for Private) Download PDF
Down syndrome screening Instructions to doctors on sending samples for Down syndrome screening Download PDF Download PDF
Request forms for
  • 1st trimester nuchal screening
  • 1st trimester (combined) screening test
  • 2nd trimester quadruple screening test
Provide upon request
Other molecular genetic testing (FISH, UPD, etc.) Request form (for HA / Private) Download PDF Download PDF
Whole Genome aCGH testing For prenatal and postnatal See below

Whole Genome aCGH testing (Resources Download)

Whole genom aCGH testing service can be requested by doctors from Hospital Authority obstetrics units and private doctors for prenatal and postnatal investigation. We will have joint counselling with clinical geneticist for fetal anomalies with abnormal aCGH results.

Basic information of whole genome aCGH testing
Diagrams for Prenatal whole genome aCGH testing
(產前晶片全基因體定量分析(aCGH)檢測圖表說明)
Download PDF
Disorders tested (from Signature Genomics) Download PDF
Autism loci (from Signature Genomics) Download PDF
Video:"How Much Can We Know about a Child Before Birth - A Look into Array Comparative Genomic Hybridisation". Lecture 2 of Explore the World of Medicine Public Lectures Series 2013 video link
Prenatal
Prenatal aCGH Pamphlet (產前晶片分析小册子) Download PDF Download PDF
Information on Prenatal whole genome array Comparative Genomic Hybridization (aCGH) Testing
(產前晶片全基因體定量分析(aCGH)檢測資料)
Download PDF Download PDF
Information for HA/Private Doctors (Prenatal)
Information to doctors on sending samples for aCGH testing (Prenatal) - HA / Private Download PDF Download PDF
Information to doctors on sending samples for aCGH testing (Stillbirth) – HA Download PDF
Request form for Laboratory Studies - HA / Private to be submitted with Download PDF Download PDF
(1) Request for aCGH study (Prenatal sample), and Download PDF
(2) Consent Form – Prenatal whole genome aCGH Testing(產前晶片全基因體定量分析(aCGH)檢測同意書), and Download PDF Download PDF
(3) aCGH charge form (for HA only) Download PDF
Charges (for private doctors) (please contact laboratory to arrange)
Postnatal
Postnatal aCGH Pamphlet (臨床患者晶片分析小册子) Download PDF Download PDF
Diagrams for Prenatal whole genome aCGH testing (for reference)
產前晶片全基因體定量分析(aCGH)檢測圖表說明 (參考資料)
Download PDF
Information for Doctors (Postnatal)
Instructions to doctors on sending samples for aCGH testing (Postnatal) - HA/Private Download PDF
Request form for Postnatal Studies Download PDF
Information on Whole genome array Comparative Genomic Hybridization (aCGH) Testing (Postnatal)
晶片全基因體定量分析(aCGH)檢測資料 (臨床患者)
Download PDF Download PDF
Consent Form – Whole genome aCGH Testing (Postnatal)
晶片全基因體定量分析(aCGH)檢測同意書 (臨床患者)
Download PDF Download PDF
Charges (Please contact laboratory to arrange)  

Scope of Service

Cytogenetic, molecular genetic, haematological and biochemical tests for prenatal screening and diagnosis

Laboratory Service

Cytogenetic tests

Karyotyping is a test to examine chromosomes in a prenatal and postnatal sample of cultured cells, which can help to identify the numerical and structural abnormalities in chromosome. The test can be performed on different tissues, including

  • Chorionic villi
  • Amniotic fluid
  • Peripheral, cord and fetal blood
  • Tissue and skin biopsy
Giemza stained karyotyping
Molecular tests

Molecular diagnostic and screening tests can provide rapid, sensitive and accurate genetic diagnosis.

  1. Rapid Aneuploidy Detection for chromosomes 13,18,21 and sex chromosomes (QF-PCR)
  2. DiGeorge syndrome (22q11.2) microdeletion Detection
  3. QF-PCR

  4. Fluorescence in situ hybridisation (FISH) analysis
    m-FISH and mBAND
    • conventional FISH
    • multi color FISH(m-FISH)
    • multi color banding (mBand)


  5. Array Comparative Genome Hybridisation (aCGH)

    aCGH is a special test which finds differences in the amount of genetic material among individuals. It is more sensitive than traditional cytogenetic Karyotyping and is able to find a chromosome gain or loss even if testing of the chromosome by Karyotyping shows normal result. For more information including request and consent forms, please visit Whole Genome aCGH testing (Resources Download).

    Array Comparative Genome Hybridisation
  6. Molecular diagnosis of other genetic conditions
    Real-time quantitative PCR Sanger DNA sequencing
    • Uniparental disomy by short tandem repeats
    • Fetal SRY DNA detection in maternal plasma
    • Fetal Rhesus(Rh) DNA detection in maternal plasma
    • Duchene muscular dystrophy (DMD)
    • Spinal muscular atrophy (SMN1)
    • Huntington disease (CAG repeats)
    • Thanatophoric dysplasia (FGFR3)
    • Apert syndrome (FGFR2)
    • Erythropoietic protoporphyria (FECH)
Reproductive medicine investigations
Down syndrome screening tests

The markers of first trimester combined screening test include maternal age, nuchal translucency (NT) and biochemical markers. Combining the marker levels together with maternal age, the risk of having a Down syndrome pregnancy can be estimated by mathematical modeling. Women are screened positive if their risks are higher than the specified cut-off value.

There are four kinds of Down syndrome screening tests offered by our laboratory

  • First trimester combined test (gestation 11-13+6 weeks)
  • Second trimester biochemical test (gestation 16 to 19+6 weeks)
  • Integrated biochemical test
  • First trimester nuchal translucency test ( for multiple pregnancy)
nuchal translucency
Haematological and genetic tests for inherited blood disorders

Thalassemia is the consequence of an imbalance in alpha and beta globin chain synthesis. Excess alpha or beta chains are insoluble in red blood cells. Precipitated globin genes damage red cell membrane thus shortening red cell half life.

Haemophilia disease is due to genetic defect in blood clotting factors impairing coagulation when a blood vessel is broken.

  • Thalassaemia screening by complete blood count and haemoglobin pattern
  • Molecular diagnosis of alpha and beta thalassaemia
  • Molecular diagnosis of haemophilia A and B (clotting factor VIII and IX deficiency)
  • Molecular diagnosis of factor VII deficiency
Thalassaemia genetic diagnosis

Staff

Laboratory Director: Dr. K.Y.K. Chan
Clinical Consultants: Dr. M.H.Y. Tang
Dr. A.S.Y. Kan
Quality Manager: Mr. P. Au

Contact and Complaint

Address: Room 210, Tsan Yuk Hospital 30 Hospital Road, Sai Ying Pun, Hong Kong
Telephone: (852) 2589-2208
Fax: (852) 2517-2373

Training

Our department is recognized by the Royal College of Obstetricians & Gynaecologists as a training centre for maternal fetal medicine subspecialists since 2000. We offer training in prenatal diagnosis and ultrasound examination for:

  • Maternal-fetal medicine subspecialists programme
  • The University of Hong Kong Master of Medical Sciences programme
  • Hospital Authority- level II obstetric and gynaecologic ultrasonography programme

Referral

  • For referrals, please call the prenatal diagnostic and counselling clinic at (852) 2589-2218, or fax referrals to (852) 2517-2373.
  • For laboratory services, please call Mrs. Wu Chung Prenatal Diagnostic Laboratory at (852) 2589- 2208.
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