In the war against uncommon and complex diseases, HKCH is armed with an arsenal of advanced equipment to provide a wide spectrum of tests for precise diagnosis, prognostication and monitoring, enabling clinicians to formulate appropriate treatment and preventive plans.

The HKCH Department of Pathology set up the only genetic and genomic division in the Hospital Authority. It conducts tests for various inherited diseases for patients and family members referred by different clinical specialties, as well as childhood cancers. Another important service is the territory-wide non-invasive prenatal testing for chromosomal disorders like Down syndrome.

HKCH is equipped with next generation sequencers (NGS) which can perform massively parallel sequencing of DNA to yield comprehensive analysis results. Dr Liz Yuen, Consultant (Pathology) said, "Different technologies have their own strengths and limitations. For diseases caused by single gene mutation or when there are classic symptoms, we may advise using conventional methods like Sanger sequencing to look at the targeted DNA fragments. But for cases without leads, such as patients presented with seizures and developmental delay, NGS has a better chance to find out what's wrong with them."

▲Dr Liz Yuen said, "As modern tests have become more and more complicated, there is a constant need for us to catch up with the latest knowledge and technologies."

Children-centred pathology services

Meanwhile, the team led by Dr Chloe Mak, Consultant (Pathology) also works tirelessly to roll out new lab tests, and special consideration is given to meet children's need. She explained, "No child likes needles. To ease their pain and anxiety, we bought analyzers that require only a little sample volume. Moreover, the reference intervals of lab results are mainly set for adults. Therefore, we make references to various literature and build up our own local data to adjust the values accordingly, so we could really tell if a child's result is normal or not."

HKCH also shoulders the task of screening all babies born in public hospitals, so they could receive timely treatment when problem is detected. Dr Mak expects more diseases to be added to the screening panel in the future to meet international standards.

Newborn screening by HKCH

• 26 inborn errors of metabolism
• Severe combined immune deficiency
• Spinal muscular atrophy (pilot)
• Glucose-6-phosphate dehydrogenase deficiency
• Congenital hypothyroidism

▲Dr Chloe Mak said. "With the low birth rate in Hong Kong, every child is precious. Newborn screening is a gift from the government, healthcare workers and parents to prepare for their life journey."

A life saved by newborn screening

"We received a phone call a few days after our daughter was born, telling us to bring her to the hospital immediately for further check-up. We feel very grateful and lucky that she was diagnosed before any infection occurred, and my bone marrow matched so I could donate it to her. Now she has recovered, and she is just like any other normal child." Baby Aaira was the first confirmed case picked up by the newborn screening programme for severe combined immune deficiency (SCID). Her father, Javed, still vividly remembers this extraordinary journey.

SCID is caused by gene mutation. Patients' immune system is very weak, so even a common cold or live-attenuated vaccine can induce repeated infections. Without treatment, infants usually die within the first two years. Dr Pamela Lee, Honorary Consultant in the Immunology team said, "Before screening is available, it would take three to four months from a patient's referral to the first treatment, which increases the risk of severe infection. Now the programme is hosted in HKCH with well-established workflow and multidisciplinary teamwork, referral time is minimized and the whole process becomes much more efficient."

When Aaira's screening result was found abnormal, she was immediately admitted into the Special Care Baby Unit of HKCH for protective isolation. Blood tests were performed and she was genetically confirmed to have SCID the day after. Since Aaira had a low T-cell count, she basically had no immunity. As an interim treatment, T-cells from her father were infused to help her develop basic resistance to life-threatening pathogens.

Aaira eventually received a haematopoietic stem cell transplant at seven weeks to rebuild a healthy immune system. Said Dr Lee, "The transplant was very successful. Now she comes back regularly for follow-up and is making good recovery progress. We can say she has a complete cure."

▲Dr Pamela Lee attributes Aaira's efficient and seamless treatment process to the collaboration across different specialties. She also thanks the Society for the Relief of Disabled Children's support in the pilot phase of the SCID screening programme, which has now become a regular public service funded by the government.

SCID treatment journey