In celebration of International Women’s Day, meet women who are advancing precision medicine in Singapore. This is Part One of our four-part series celebrating the achievements of women in STEM.
Precision medicine, integrated into healthcare, has the potential to yield more precise diagnoses, predict disease risk before symptoms occur, and design customised treatment plans that maximise safety and efficiency. But how far are we from realising these gains in paediatrics—and medicine?
Associate Professor Tan Ee Shien who holds concurrent appointments as Head & Senior Consultant, Genetics Service, KK Women’s and Children’s Hospital (KKH), and Deputy Chief Medical Officer at PRECISE, offers insights on Singapore’s paediatrics landscape today—and how precision medicine can make a difference to children, families, and the Singapore population.
Precision medicine is not a young practice in paediatrics
Associate Professor Tan shares, “Precision medicine at its core really just means the use of one’s genomic information for health purposes. For over 30 years now, our team at KKH has been providing clinical care to children with genetic disorders—so we have been using genetic testing in the diagnosis of medical conditions in children for quite a while now. And whether it is the technology or the know-how, we have kept abreast and progressed with prevailing industry practices.
“However, unlike some of the other diseases such as cancers, genetic disorders in children tend to manifest as rare diseases—with a prevalence of approximately one in 2,000 individuals. These conditions are rare individually. But if you look at them as a group, they are actually more common than you think. Because these conditions are lesser known, the public knowledge is understandably low.”
Paediatrics before next generation sequencing
Before the emergence of next generation sequencing in mid-2000s, genetic sequencing was costly and only one fragment of the gene could be sequenced at a time. Associate Professor Tan says, “It used to cost about S$2,000 to sequence one gene and that is out of the 20,000 that we have. That is why we relied a lot on clinical symptoms and clinical signs when we came across children with serious illnesses in the past. We would try to put everything together to derive the diagnosis. However, because these are very rare conditions, it is often hard to get a diagnosis.”
“With the setup of BRIDGES (Bringing Research Innovations for the Diagnosis of GEnetic diseases in Singapore) by KKH in collaboration with genomic research institutes at SingHealth, Agency for Science, Technology and Research (A*STAR) and Duke-NUS in 2014, we started using exome sequencing on children with undiagnosed diseases. We began to see a higher rate of diagnosis.”
Associate Professor Tan continues, “This was an important development—because it means a lot for the family to know what is causing the problem or simply be able to put a name to the condition. It helps them to accept what is happening, prepare for the future, and connect with others with the same genetic condition.”
An important developmental milestone of precision medicine in paediatrics
It is clear that precision medicine has contributed greatly to paediatrics as a diagnostics tool. Particularly, it complements the newborn screening programme at KKH, which aligns with goals outlined in the Healthier SG white paper. Associate Professor Tan shares, “Our newborn screening programme currently uses biochemical assays to detect about 40 metabolic genetic disorders before symptoms become present. On average, we make one diagnosis in every 3,000 newborns.
“With newborn screening, our goal is to give the best chance for intervention and early treatment so that the newborn has an opportunity for the most favourable prognosis. And of the conditions that we have detected with the programme thus far, some of them used to present with devastating illness in the first weeks of life. We managed to prevent that from happening with this programme.”
“Genomics can potentially complement the biochemical assays currently used. It will give us the capability to detect more diseases and a wide range of different conditions. Whereas common vitamins are all that are needed for some conditions, there may be another group of conditions where no direct treatment is available. But simply because we know the likelihood of disease occurrence, we can take preventive steps and apply therapy early—basically being more prepared to handle the medical complications,” Associate Professor Tan explains.
Ensuring a healthy growth trajectory for precision medicine
Associate Professor Tan elaborates, “We are not far from realising some of these opportunities precision medicine offers. Like the use of genomic screening for newborns—the technology is already there, and some countries have piloted studies on it. We do however need to set up the framework, the workflow and—most importantly—determine if this is what Singaporeans need and want. This is one example of how genomics can be made relevant to the health of our population.”
Associate Professor Tan adds, “And let’s not forget that precision medicine has the potential to benefit not just paediatrics. It can also have a positive impact on the health of our general population. We have seen exciting advances both in technology and our knowledge in genomics. Question is, can we build a platform where a person on the street can gain access to their genomic information, get the right counsel to understand results, and eventually use this knowledge to better their health? However, for genomics to be used in everyday health practice, the general population needs to first understand how precision medicine can have an impact on them.
“From my perspective, there is a consistent aim for precision medicine—to harness the power of genomics to improve health for all, children and adults.”
 Johnson KB, Wei WQ, Weeraratne D, Frisse ME, Misulis K, Rhee K, Zhao J, Snowdon JL. Precision Medicine, AI, and the Future of Personalized Health Care. Clin Transl Sci. 2021 Jan;14(1):86-93. doi: 10.1111/cts.12884. Epub 2020 Oct 12. PMID: 32961010; PMCID: PMC7877825.