Inborn Errors of Metabolism (IEM)
Inborn errors of metabolism are rare disorders caused by genetic defects that affect the body’s ability to break down particular nutrients found in food e.g. amino acids. Most often inherited from both parents, they are usually caused by defects in enzymes that help break down (‘metabolise’) food. This in turn can lead to a harmful build-up of certain chemicals, which, if not managed, can cause a wide array of symptoms including delays in physical and mental development.
Inborn errors of metabolism such as phenylketonuria or maple syrup urine disease occur in 1 in 10000 and 1 in 250000 children respectively. Although, these conditions are considered rare, as a group they account for more than 5% of all pediatric hospital admissions.
Often, an early diagnosis and a special diet are the only ways of treating these disorders.
Newborn screening is important for the early detection of IEM, aimed at the earliest possible recognition and management of affected newborns and thus helps prevent the morbidity, mortality and associated disabilities. Newborn screening is mandatory in many countries worldwide but not so far in India.
A special diet, usually for life is the basis for a normal development of affected patients. Management of inborn errors of metabolism is usually through a lifelong commitment to a restricted diet. In the example of the amino acid disorder Phenylketonuria (PKU), individuals cannot break down the amino acid phenylalanine, which leads to a build-up on the brain. A build-up of this kind can cause long-term health issues, including irreversible brain damage. Since amino acids such as phenylalanine are the building blocks of the protein we eat, PKU patients must stick to a low-protein diet, alongside supplementation of the essential and non-essential amino acids that our bodies need to function properly. Regular monitoring and medical supervision is very crucial as part of management of IEM.
New Born Screening (NBS)
Newborn screening aims to detect rare conditions that can lead to serious illness, developmental problems and even death. Early detection helps to prevent irreversible damage to baby even before symptoms appear.
Newborns are screened with a simple heel-prick blood test, drawing just a drop of blood in first few days of life. The sample is taken on a filter paper, dried and sent for testing in a central laboratory. This simple test can screen newborns for 30 genetic disorders.
NBS identifies suspected cases of rare genetic disorders; however, suspected cases need to be confirmed with another set of tests. The rate of confirmed cases is very low among the suspected cases. Non-detection and delayed treatment can cause severe disabilities in babies. NBS could very well help to avert a lifetime regret and give a second chance to babies for normal life.