Screening them at birth

Star: The mystery has haunted many grieving parents: why do their normal, healthy babies suddenly become handicapped or mentally retarded? But such are the insidious effects of infants with Inborn Errors of Metabolism (IEM), inherited metabolic diseases that comprise a large class of genetic diseases.
“A baby may be well until suddenly at three years old, he or she dies of a heart attack,” said Dr Choy Yew Sing, geneticist-cum-metabolic-specialist at the Kuala Lumpur Hospital (KLH).
Cases detected in Malaysia are just the tip of the iceberg. Many have gone unnoticed because the symptoms are common: heart attack, stroke, poor feeding, fits, comatose, behavioural problems, hearing or visual problems, bleeding in the head, vomiting blood or autism, he said.
“Deficiency in enzymes due to defective genes can affect any organ in the body,” explained Dr Choy, who diagnoses at least four new cases weekly. “If untreated, they may cause mental retardation, physical handicap and even death.
“Many of the diseases resulting from IEM are treatable, if only they are detected early,” he said.
Hence, newborn screening, early diagnosis and appropriate management would save the child and prevent mental retardation and physical handicaps, he said.
He said, generally, treatment would be futile when a child reached age seven.
An affected individual inherits the defective gene from both parents who are carriers but are themselves normal.
Examples of the more common IEM are: G6PD deficiency, maple syrup urine disease, urea cycle defects, methylmalonic academia, mucopolysaccharidosis and mitochondrial disease.
The symptoms range from mild to severe. The condition usually affects babies although some symptoms are manifested only in adulthood, said Dr Choy.
He said if the symptoms indicate usual health problems, proper standard treatment would rectify them.
But with IEM, the problem will recur and worsen, even after treatment.
He said the problem cuts across all ethnic groups; marriage between relatives increases the risk.
He said the lack of expertise and IEM testing facilities has resulted in the lack of detection. There are only three geneticists in Malaysia who are trained to detect IEM, and only the Institute for Medical Research and Kuala Lumpur Hospital have the facilities and expertise to conduct the tests, said Choy.
The screening process for IEM includes special blood (serum amino acid) and urine (uric organic acid) tests of newborns by using the technology called tandem mass spectrometry.
Currently, there are more than 1,000 patients on record. Since one in 1,500 children is born with the condition, there may be more than 300,000 cases a year from the 500,000 babies born in Malaysia every year, said Dr Choy.
The Health Ministry had initiated the project to look into the feasibility of screening all newborn babies for genetic metabolic disorder. The two-year project is currently being carried out at government hospitals in Kuala Lumpur, Putrajaya, Selayang, Alor Star, Penang, Kota Baru, Kuching and Malacca, said Dr Choy.
“We want to see how prevalent IEM is in our population and how feasible the treatment process is so that we can plan for the health needs of the population,” he said.
“Screening babies at birth allows for early treatment and preventing complications,” he said. “It also reduces the extent of brain damage and organ failure.”
Depending on the type of IEM, patients can be treated with special diet, vitamin supplements, medications, enzyme replacements, liver transplants or bone marrow transplant, said Dr Choy.