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KKH develops test to diagnose rare diseases faster

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KKH doctors develop DNA sequencing that has been used on children

For the first year of her life, a baby girl fought multiple infections that left doctors at KK Women's and Children's Hospital (KKH) puzzled because they could not diagnose the root cause of her problems.

Rashes would break out, there was a huge ulcer on her buttocks that needed to be drained, and there was milky fluid in her lungs. When one problem was treated, another would surface.

For nine months, doctors put her through various tests, with no success - until they checked her genomic make-up with a new rapid sequencing test developed in-house by KKH doctors.

They found her immune function was compromised. They did a total bone marrow transplant and the girl went home.

After a year, her body rejected the transplanted stem cells. She died at the age of 21/2. She was one of four known cases in the world with this genetic disorder.

Dr Saumya Shekhar Jamuar, a senior consultant specialising in genetics in children, said the girl had at least a year of normal life, without the suffering she experienced in her first year of life.

The KKH genetics team developed the test to provide faster diagnosis of rare diseases. They have sequenced 380 children since 2014 and were able to diagnose the problem for two in five of them.

They plan to use the sequencing initially on about 50 children a year who are in intensive care, where doctors have difficulty diagnosing the problem. It can be used on another 200 to 250 people a year whose ailments are proving hard to pin down.

BLOOD

Under this test, blood is taken from the child and the DNA is sequenced. The variants are identified and compared with ethnic-specific reference points to see what could be responsible for the illness.

In some cases, after the cause was identified, the doctors changed the way they were managing the children. In others, it did not make much difference except to let the family know exactly what was wrong.

A couple had two children with underdeveloped brains who had died shortly after birth.

The doctors identified the culprit gene and informed the couple there was a 25 per cent chance of the same issue occurring in future. The couple have opted for in-vitro fertilisation so the embryos can be tested for this gene before the implant.

In some cases, when no cure is available, the parents have "closure" in finding out what is wrong with their child.

Madam Serene Poh, knew something was wrong when her son Jayden Tan was late holding up his head, and could not even crawl when he was 11/2 years old. He could not talk either and had difficulty swallowing.

The gene test identified his problem as Pura syndrome, a neurodevelopmental disorder. Now 12, he is the only person here known to have this.

The oldest survivor with Pura syndrome is a 28-year-old woman, which gives Madam Poh hope. He is the second of her four children.

He underwent physio-, occupational and speech therapies at KKH and can walk unaided for about 200m. He does not talk, but understands what is said.

KKH is not the first to do such genetic sequencing.

But the doctors said one advantage of developing it locally is getting an Asian gene pool, which might be different from that of Caucasians.

The test costs the hospital $3,600 to $6,000. Overseas, it is priced at $8,000.

MEDICAL & HEALTH