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CapitalBio Deafness Test Being Evaluated for Neonatal Screening in Three Major Chinese Cities


BEIJING — Like many microarray vendors, CapitalBio sees future growth opportunities in molecular diagnostics. But from its headquarters here in China's capital city, the firm is perhaps better positioned than some others to capitalize on the country's expanding demand for genetic tests.

This year, three Chinese cities began evaluating one of CapitalBio's products, the Deafness Gene Mutation Detection Array Kit, to screen approximately 250,000 newborns for hereditary susceptibility to hearing loss. Specifically, about 220,000 babies will be screened with the arrays in Beijing, another 30,000 in Chengdu, and an additional 10,000 in Dalian.

Depending on the outcome of the evaluation, the cities may implement CapitalBio's test as part of routine newborn screening, and the company has hopes that its array could eventually be used nationwide.

"The hope is that they will move to using it but we can't make a prediction and say it will happen," said Keith Mitchelson, vice president of international business development and marketing at the firm.

Still, at CapitalBio's headquarters last week Mitchelson told BioArray News that 50,000 newborns have already been screened with the array since the project kicked off in April, resulting in the identification of hearing-related mutations in 140 children.

And, he noted, when a child is discovered to be a carrier of a particular 12S rRNA mutation that makes the individual sensitive to aminogylcoside drugs, it typically leads to additional testing within the affected child's family. Carriers of this mutation are warned to avoid taking these antibiotics, which are known to cause deafness.

"Because this particular mutation is maternally inherited, one can go to all the maternal relatives and test them, so there may be as many as 10 people who can be identified in addition to that child who will have that condition," said Mitchelson.

Another condition that the test detects is enlarged vestibular aqueduct syndrome, or EVAS. People with EVAS are sensitive to pressure-induced hearing impairment, so mutation carriers are warned to avoid intense sports. CapitalBio claims that knowledge of these two defects can help prevent the affected child being exposed to adverse conditions, and thus prevent deafness. Identification of other mutations using the kits can help to identify hearing impairment at birth, so that educational programs to stimulate language can begin immediately.

According to the firm, the Deafness Gene Mutation Detection Array can be used to detect nine polymorphisms in four genes — GJB2, GJB3, PDS, and 12S rRNA. The mutations cover 98 percent of GJB2 found in the Chinese population, 80 percent of PDS mutations, and 90 percent of 12S rRNA mutations. The array is manufactured by CapitalBio and the assay can be run using its instrumentation.

"Overall, the mutations detected cover just over 80 percent of hearing-related gene mutations found in affected Chinese patients," said Mitchelson. "So the current array test covers the major encountered mutation spectrum in China."

He added that Chinese hospitals that have adopted the chip have started to report on its usefulness. Earlier this year scientists from the China Rehabilitation and Research Center for Deaf Children in Beijing described in a paper the use of CapitalBio's array to conduct mutational analysis of the SLC26A4 gene in Chinese sporadic nonsyndromic hearing-impaired children. They concluded that genetic factors were important causes for sporadic nonsyndromic hearing loss in Chinese pediatric cases.

Year of the Dragon

CapitalBio's Deafness Gene Mutation Detection Array Kit is one of several tests from the firm to be cleared by the Chinese Food and Drug Administration in recent years. The company also sells array-based in vitro diagnostics for detecting tuberculosis drug resistance and identifying mycobacteria. While 12-year-old CapitalBio has traditionally offered array consumables for research — as well as hardware, such as its LuxScan HT24 Microarray Scanner and SmartArrayer 136 for spotting arrays — the company in recent years has intensified its focus on the diagnostics market.

"When we started, we were making chips for the life science research market," said Mitchelson. "We are still making these arrays, but we have just expanded to this new area," he said of the diagnostics market.

Mitchelson added that the Chinese government is keen to adopt new technologies for genetic testing. As the country has followed its one-child policy since the late 1970s to stem overpopulation, Mitchelson said that Chinese parents have a "huge interest" in understanding the genetic health of their children from an early age.

According to Mitchelson, that interest intensified this year, which is the Year of the Dragon in China's 12-year-cycle zodiac, and considered a favorable sign to be born under. "Everybody wanted to have children in the Year of the Dragon, so the birthrate went up this year," he said.

And in line with that increase, the Beijing Municipal Government embarked on its neonatal deafness gene mutation screening project, using CapitalBio's chip to examine the genetic status of 200,000 newborns in Beijing so far this year. According to a government statement, the Beijing Municipal Government already offers neonatal screening for phenylketonuria, congenital hypothyroidism, congenital heart disease, and congenital dislocation of the hip.

In the same statement, the government said its project has a budget of about $30 million. Since April, dry blood spots collected from newborn children have been analyzed at six central clinical laboratories, including the Beijing Tongren Hospital, the PLA General Hospital, the Peking Union Medical College Hospital, the Beijing Children’s Hospital, the Peking University Third Hospital, and the China Rehabilitation and Research Center for Deaf Children.

In addition, CapitalBio has been running the samples in its own laboratories, Mitchelson said.

According to the statement, about 60,000 hearing-impaired children are born in China each year and about 6 percent of the Chinese population carries genetic deafness mutations. Project organizers believe that by screening newborns with the array, they can reduce healthcare costs by directing earlier appropriate health care to families.

When asked if CapitalBio's test could be used in other regional markets, such as the US or Europe, Mitchelson noted that "different populations have different proportions of polymorphisms that are important."

"We have been asked in the past about producing arrays for different populations in Europe or the Middle East, but those populations are very different from the Chinese population, so we haven't done that," he said. Still, he hinted that wider adoption in China could set up an entry into other markets, if partners see the value of the test.

"If this test is successful here, it provides good marketing material for taking it into other markets," he said.

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