Screening newborns for two metabolic disorders takes off

Published in The Hindu on March 20, 2008

After much delay, the screening of one lakh newborn babies over a three-year period for two inborn errors of metabolism — hypothyroidism and adrenal hyperplasia — will start soon. The screening will take place in Chennai, Mumbai, Delhi, Kolkata, and Hyderabad, and each city will screen 20,000 newborns.

Pilot mode

While screening for these disorders, as well as others, is mandatory in the developed countries, the newborn screening programme, which is taken up on a pilot mode, will start only now.

“We have been brainstorming for the last 3-4 years,” said Dr. Vasantha Muthuswamy, Senior Deputy Director General, ICMR, New Delhi. “We are doing this on a research mode to gather data.”

The study is aimed at detecting and treating the disorders as soon as the baby is born.

“Ideally hypothyroidism should be detected from 48 hours after birth to 30 days. Delay of each day matters a lot,” noted Dr. Sujatha Jagadeesh, Consultant Geneticist at Mediscan, Chennai. Mediscan is the centre that will undertake the screening in Chennai.

While hypothyroidism affects brain development, adrenal hyperplasia leads to ambiguity in genital area in girl babies. The time of detection holds the key in reducing the amount of damage.

Later symptoms

When detected and treated early, children will not show any symptoms. But any delay in detection will result in children showing up symptoms later in life. While many metabolic disorders can be screened, the programme has zeroed in on the two disorders as they are common in India.

These disorders are easy to detect and treat. And the treatments are not expensive. “We are screening for the disorders wherever intervention is possible. Otherwise it is ethically not right,” Dr. Muthuswamy said.

Preliminary data

Though the prevalence of these disorders in the country is not known, preliminary data based on ICMR’s multicentric newborn screening pegs the prevalence of hypothyroidism at 1 in 2,500 and 1 in 3,700 in the case of adrenal hyperplasia.

Mediscan in Chennai has screened 800 newborns at a government maternity hospital in Chennai and 1,600 at a corporate hospital in the city in the last eight months.

“We have not seen any positive cases. But the number is too small to draw any conclusions,” said Dr. Jagadeesh.

Newborn screening

The newborn screening project undertaken on 23,000 children during 1999-2004 by the Hyderabad based Centre for DNA Fingerprinting and Diagnostics (CDFD) found the prevalence of the two disorders to be much higher.

“We found 1 in 1,800 newborns affected by hypothyroidism and 1 in 2,200 by adrenal hyperplasia,” said Dr. Radha Rema Devi, Genesticist at CDFD, Hyderabad. This screening was restricted to Hyderabad.

Rural communities

CDFD has already started the newborn screening this January and has screened 800 babies so far. ‘Our programme is of little different. Dr. Devi said, “we plan to look at the rural communities in East Godavari District where consanguineous marriage is common.”

Mediscan, on the other hand, intends to screen a mixed population. It will target the Government Maternity Hospital in Chennai as well as private hospitals.

Whatever be the population studied, at least 95 per cent of newborns have to be screened to get any meaningful result.

According to Dr. Muthuswamy, ICMR plans to gradually include newborn screening for other diseases at a later date.

To run concurrent with the newborn screening programme will be the screening of 500 children who already have symptoms of the two disorders. This will be done at NIMHANS Bangalore. “This is to see our capability to detect these diseases. We may expand the number of diseases screened,” said Dr. Muthuswamy.