HomeProjectsBiomedical Sciences and Healthcare TechnologiesGenetic Testing for Hearing Impairment

Genetic Testing for Hearing Impairment

Project Quick Facts

Principal Investigator

  • Dr. CHOY Kwong Wai

    Department of Obstetrics and Gynaecology

  • Funding

    Innovation and Technology Commission

  • Collaboration

    1) Angsana Molecular & Diagnostics Laboratory(HK) Ltd

    2) Clinical Genetic Service, Department of Health

    3) Havard Medical School

    4) Paramount Medical Center

    5) Suzhou Municipal Hospital

Hearing impairment is one of the most common birth defects worldwide with the incidence of 1 in 500. In China, it has been estimated that over 27 million people are with hearing and speech disabilities. Of which more than 60% of these hearing impairment is caused by genetic factors.

Department of Obstetrics and Gynaecology pioneered hearing loss SNaPshot® genetic testing for screening of hearing impairment. This comprehensive hearing loss genetic test would help provide better medical service for the Hong Kong residents by expanding the detection list from four genes to 125 genes. By acquiring the genetic information, it will be not only translated to an improved ability to diagnosis of hearing loss patients themselves, but also carry out the prenatal diagnosis and preimplatation diagnosis for their families. It also helps medical planning and disease prognosis. Once genetic diagnosis confirmed on the phenotype-free family members, early intervention should be started for better social and academic adoption.


Except the above-mentioned hearing loss genetic test, Department of Obstetrics and Gynaecology also provides many other genetic testing or screening, include:

Fetal DNA Chip version 2.0

The Fetal DNA Chip testing was first launched in Hong Kong in 2009 by our department. It is specifically designed to detect microdeletion/ microduplication syndromes which would not be detected by conventional karyotype analysis. Currently, the upgraded version (2.0) also enables the detection of uniparental disomy.

Postnatal DNA Chip

Our department, in collaboration with Baylor College of Medicine in the United States, offers Postnatal DNA Chip service. The Postnatal DNA Chip testing uses Chromosomal Microarray Analysis (CMA) designed by the Baylor Medical Genetics Laboratories. The Postnatal DNA Chip can detect common micro-deletion/ duplication syndromes including over 130 recognized genetic syndromes and other rare genetic disorders reported to be associated with mental retardation and/ or physical problems.

Fragile X Carrier Screening

Fragile X syndrome (FXS) is the most common inherited form of intellectual disability. FXS is caused by a defected FMR1 gene located on the X chromosome, in which there is an increased number of unstable trinucleotide repeats. Overexpansion of >200 repeats cause FXS with mental retardation and autism. Carriers with an increased repeats may have variable degree of health problems. Premutation carriers are at risk of transmitting the defected gene to their offsprings, and other health problems, they should be counselled by a genetic counselor. Pregnant carriers may need prenatal diagnosis. Genetic counseling and prenatal diagnostic services are available in our department.

Preimplantation Genetic Diagnosis / Screening (PGD/PGS)

Preimplantation Genetic Diagnosis/Screening (PGD/PGS), as offered by the Department of O&G (CUHK), is the latest diagnostic/screening test performed on embryos to identify single gene disorder/chromosomal abnormalities. PGS uses array comparative genomic hybridization (aCGH) technology to evaluate the total number of chromosomes in a single cell and determines any gain or loss of chromosomes. Whereas PGD is used to screen for monogenic disorders and detect the pathogenic mutation(s) in the causal gene(s), its main advantage is to avoid selective termination of pregnancy as this method makes it possible to transfer an embryo free of the genetic disease under consideration.

Do you like our project?