Dr. Rossa Chiu, Chinese Uni. Of Hong Kong, Talks To Asian Scientist Magazine

We speak with CUHK’s Prof. Rossa Chiu Wai Kwun, a doctor who has developed a safer, non-invasive technique for fetal genetic testing.

AsianScientist (Aug. 16, 2011) – Professor Rossa Chiu may not yet be a household name, but her research on fetal genetic testing might just become beneficial to many households in the near future.

At present, genetic testing of the fetus during pregnancy for conditions such as Down’s Syndrome involve invasive procedures which carry a small but significant risk of miscarriage. Chorionic villus sampling (CVS) and amniocentesis are two such procedures which are usually performed between weeks 10-12 and weeks 15-18 respectively.

Women looking for a safer alternative for fetal genetic testing have been disappointed, until now. A technique to detect fetal DNA in the mother’s circulation has been developed by Prof. Chiu and her Hong Kong-based team, which may lead to a much safer, non-invasive technique compared to those currently in use.

Her work has quickly gained international recognition and Prof. Chiu, who studied medicine at the University of Queensland, has recently been selected by the Heads of Academic Departments of Clinical Biochemistry in the UK to receive the Professors’ Prize for 2011. She was also recently awarded the 2011 International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Young Investigator Award which is sponsored by pharmaceutical giant Roche.

While these might be her most prestigious awards, Prof. Chiu, who is in her mid-thirties, is no stranger to accolades. Since embarking on a career in chemical pathology research in 1999, she has published over 100 peer reviewed journal articles on circulating nucleic acids in internationally renowned high impact journals – work that has earned her the Young Scientist Special Award 2002 from the Hong Kong Institute of Science and Young Researcher Award 2005 by the Chinese University of Hong Kong, amongst others.

Research aside, Prof. Chiu’s other passion is teaching undergraduate medical students, an undertaking which has earned her the Teacher of the Year award for five consecutive years.

Asian Scientist Magazine had the honor of speaking to this remarkable woman regarding her latest research and its global impact.

The non-invasive prenatal testing technique you have pioneered is very exciting. Are there any limitations to the technique? Can your methods be applied to screen for other genetic diseases?

Regarding limitations, the current version of the test cannot be applied to multiple gestations. In addition, the test is relatively expensive at about US$1,000 per sample. However, we are hopeful that the costs would drop with the fall in the costs of next-generation sequencing.

Yes, we have applied next-generation sequencing and developed methods that would allow us to decode almost the entire fetal genome by analyzing a blood sample from the pregnant woman. The data was published recently at Lo YMD et al. 2010 Sci Transl Med 2010;2:61ra91.

In principle, it means that we could potentially diagnose virtually any inherited diseases non-invasively. However, the analysis described in the paper cost US$200,000 just to analyze one case. Thus, we are currently working on more cost-effective methods.

Can this test be used at any gestational age of the fetus? if not, by what gestational age can you test?

The non-invasive test for Down syndrome detection can be applied to any gestational age as long as adequate amounts of fetal DNA are present in the maternal circulation.

In our study, we have analyzed samples from the 10th week of gestation. We know that fetal DNA can be detected in maternal plasma from the first trimester of pregnancy and the concentration increases until term.

Our sequencing test is different from the ultrasound and maternal serum biochemistry tests that are in current use for Down syndrome. These tests aim to detect phenotypic (physical) features that are associated with Down syndrome. Such features are prominent only at certain gestational age period.

On the contrary, our sequencing test aims to detect extra amounts of chromosome 21 DNA in maternal plasma which should exist across all gestational ages if the fetus has trisomy 21.

How did you come into the field of chemical pathology research? As a medical student, did you know think you would work in this field? If not, what were your career interests back then.

As a medical student, I very much enjoyed the process of logical deduction in formulating a working diagnosis. I liked the subjects: biochemistry, pathology, and medicine, in particular.

However, I have never thought of a career in research when I was a student. I went to medical school in Queensland, Australia, at a time when securing a specialist training post was difficult. Thus, the possibility of pursuing an academic post did not seem to be an option at that time. Just months before my graduation, I applied and ended up doing my internship in Hong Kong instead of in Australia.

After one year of internship training in Hong Kong, I reviewed what I had always liked as a medical student. I decided that I would pursue training in Pathology which would allow me to make scientific observations and logical deductions as part of the job.

I was fortunate enough to be offered a medical officer post at the Department of Chemical Pathology, Prince of Wales Hospital, Hong Kong. Prince of Wales Hospital is the teaching hospital of The Chinese University of Hong Kong.

Within months of starting the job, there was an opportunity to become a lecturer in the Department. Not fully realizing the demands of the post, I took up the academic appointment with the thought that I could learn about research on the job. I have stayed in the Department since then.

Prof. Rossa Chiu with her research team (Source: CUHK).

What difficulties do you envisage in making non-invasive prenatal diagnosis a common practice worldwide?

I do not foresee any major difficulties. The “difficulties” would be the standard issues one need to face whenever a new test is introduced into medical practice. Thus, the issues that we would be facing include:

  • How to incorporate the non-invasive tests into the existing prenatal screening programs? Consensus and recommendations would need to be reached among the obstetrics community.
  • To work through the standard regulatory steps for introducing new medical tests at different localities around the world.
  • Logistical issues would include personnel training, set up of laboratories and so on.

From invasive diagnostic tests for Down syndrome such as CVS and amniocentesis, to the less invasive technique you’ve pioneered, the face of prenatal testing has certainly changed. Do you think prenatal tests could get less invasive, or are we already there?

As shown by our publication and those by others, I think the non-invasive test for Down syndrome detection is ready to be used as a second tier screening test to help reduce the number of unnecessary invasive procedures being performed.

Current screening programs identify about five percent of pregnancies as being high risk and definitive diagnosis by invasive testing would be an option. However, Down syndrome generally affects 1 in 700 pregnancies (i.e. 0.14 percent of all pregnancies). This means that the majority of the 5 percent of pregnancies are undergoing the invasive tests unnecessarily.

If we apply the sequencing test to those high risk cases, we would be able to tell 98 percent of those who are carrying an unaffected baby that they need not worry. In this way, the number of women needing to proceed to invasive testing would be reduced by 98 percent.

Our group is planning to launch the testing service for Down syndrome in 2012. Furthermore, as discussed in the first question, the option to test other genetic diseases is coming.

There has been a serious problem with sex-selective abortions in India and in China. Do you think non-invasive prenatal testing would exacerbate the problem?

Fetal gender can already be determined non-invasively by other means, such as ultrasound scanning. Thus, in my opinion, the problem is not with the tests but with the abuse of the tests.

Apart from prenatal testing, what are your other research interests?

I study novel methods for disease diagnosis. For example, I am also investigating ways to improve early diagnosis of liver diseases.

Asia’s R&D growth has been phenomenal, but this growth has not been even throughout the region. Do you think Hong Kong has positioned itself for success, and has the government done enough to help researchers like yourself?

Research is very competitive and there is no guaranteed success. I think the research environment in Hong Kong is acceptable. The government is continuously improving its efforts to facilitate research. An advantage that Hong Kong has is that the community is very adaptive. We are always ready for change and improvement.

To read more about Prof. Chiu’s research:
Dr. Chiu Wai Kwun, Rossa’s lab website


Copyright: Asian Scientist Magazine. Photo: CUHK.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Rebecca Lim is a Singaporean-born medical doctor practising in Melbourne, Austraia. She earned her MBBS degree from Monash University, Australia.

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