Cri­sis of trust hits pop­u­lar­ity of pre­na­tal ge­netic tests

China Daily (Latin America Weekly) - - China -

Kline­fel­ter syn­dromes, which re­sult from miss­ing or du­pli­cated sex chro­mo­somes.

“The amount of fe­tal DNA in the blood sam­ple in­flu­ences the ac­cu­racy of the test. Also, since the DNA be­ing tested comes from the pla­centa and not di­rectly from the fe­tus, there is a very, very small pos­si­bil­ity that the DNA we de­tect is not that of the fe­tus, which would lead to an in­ac­cu­rate re­sult,” he said.

Ac­cord­ing to Zhou, the mother’s gen­eral health can also in­flu­ence the ac­cu­racy of the test; for ex­am­ple, if she is over­weight, has can­cer, au­toim­mune dis­ease or has had an or­gan trans­plant. In ad­di­tion, the test is not rec­om­mended for women car­ry­ing more than one fe­tus.

Greater pro­vi­sion

To re­duce the rate of birth de­fects, the Na­tional Devel­op­ment and Re­form Com­mis­sion’s 13th Five-Year Plan (2016-2020) em­pha­sizes the im­por­tance of im­prov­ing med­i­cal ser­vices be­fore and dur­ing preg­nancy. The com­mis­sion has set goals of rais­ing the amount spent on test­ing to 800 mil­lion or 1 bil­lion yuan ($116.5 mil­lion to $145.7 mil­lion) a year by 2020 and pro­vid­ing gene tests for half of the to­tal new­born pop­u­la­tion.

“Lots of par­ents have very high ex­pec­ta­tions of NIPT. Most peo­ple fo­cus on its safety and high ac­cu­racy rate, but they know lit­tle about the tech­nol­ogy it­self and are unaware of the po­ten­tial for in­ac­cu­rate re­sults,” Duan said.

Re­ports sug­gest that many women were given the all­clear by NIPT but later gave birth to chil­dren with phys­i­cal or men­tal dis­abil­i­ties be­cause the test was per­formed by a physi­cian who ei­ther did not in­form the par­ents of a pos­si­ble false re­sult or failed to con­duct fur­ther tests, even after see­ing ul­tra­sound re­ports that in­di­cated po­ten­tial prob­lems.

“Doc­tors play a cru­cial role in in­form­ing moth­ers and mak­ing the de­ci­sion to con­duct fur­ther tests, even if the NIPT re­sult is neg­a­tive,” said Zhu Haiyan, direc­tor of the Pre­na­tal Di­ag­nos­tic Cen­ter at the PLA Navy Gen­eral Hospi­tal in Bei­jing.

Prac­ti­cal dif­fer­ences

NIPT has been used in the United States since 2011. In March 2016, the Amer­i­can Col­lege of Ob­ste­tri­cians and Gyne­col­o­gists and the So­ci­ety for Ma­ter­nal-Fe­tal Medicine re­leased two prac­tice guide­line bul­letins to clar­ify the pur­poses of and dif­fer­ences be­tween pre­na­tal ge­netic screen­ing and pre­na­tal ge­netic di­ag­nos­tic test­ing.

Be­cause screen­ing tests re­turn both false-pos­i­tive and false-neg­a­tive re­sults, they must be con­firmed via di­ag­nos­tic test­ing for chro­mo­so­mal dis­or­ders, such as am­nio­cen­te­sis (tests of the fluid sur­round­ing the fe­tus in the uterus) and sam­pling of chori­onic vil­lus (minute ves­sels that help form the bor­der be­tween ma­ter­nal and fe­tal blood sup­plies).

How­ever, di­ag­nos­tic tests are un­pop­u­lar, ac­cord­ing to Zhu. “Am­nio­cen­te­sis is in­va­sive, and many moth­ers worry about the pos­si­ble risk it could trig­ger a mis­car­riage. In prac­tice, the rate is usu­ally less than 1 per­cent, and an ex­pe­ri­enced doc­tor could re­duce it to less than 0.1 per­cent,” she said.

“The prob­lem is the poor train­ing given to med­i­cal staff in some clin­ics, es­pe­cially in third- or fourth-tier cities. Some doc­tors place too much trust in gene tests and don’t pro­vide moth­ers with the nec­es­sary in­for­ma­tion about the pro­ce­dure.”

In the US, ACOG re­quires an ob­ste­tri­cian or other health­care pro­fes­sional, such as a ge­netic coun­selor, to dis­cuss the re­sults of screen­ing tests with moth­ers and help them de­cide what to do next.

In 2016, the NHFPC — now su­per­seded by the Na­tional Health Com­mis­sion — re­leased a guide­line stat­ing that women in China pre­par­ing to un­dergo a pre­na­tal DNA test must be made aware of the pos­si­bil­ity of false re­sults, and re­quired them to sign an in­formed con­sent. The guide­line also em­pha­sized that screen­ing should not be re­garded as fool­proof.

“How­ever, many peo­ple don’t read the in­formed con­sent care­fully enough or are un­able to un­der­stand the po­ten­tial for false re­sults with­out the help of a med­i­cal pro­fes­sional,” Zhu said.

“In China, we have no ge­netic coun­selors, and ob­ste­tri­cians in large hos­pi­tals see about 30 pa­tients in a half-day ses­sion, so they don’t have time to pro­vide per­son­al­ized con­sul­ta­tions, which means some pa­tients un­der­stand the facts bet­ter than oth­ers.”

The PLA Navy Gen­eral Hospi­tal’s pre­na­tal cen­ter screens about 1,000 NIPT cases a year. Zhu said many pa­tients who at­tend have al­ready had the test at small clin­ics in third- or fourth-tier cities but need a re­peat be­cause some clin­ics em­ploy un­re­li­able gene test­ing com­pa­nies that don’t give pa­tients a de­tailed re­port on pa­per, but sim­ply send the re­sult via text mes­sage.

Cost is cru­cial

Yu Jun, for­mer deputy head of the Bei­jing In­sti­tute of Ge­nomics at the Chi­nese Academy of Sci­ences, said cost is a cru­cial fac­tor to ob­tain­ing ac­cu­rate re­sults.

“NIPT tech­nol­ogy has been proven safe and use­ful. Most test providers in China use next-gen­er­a­tion se­quenc­ing plat­forms and reagents made by com­pa­nies over­seas. In other words, the ac­cu­racy, cost and ef­fi­ciency of NIPT is al­ways re­liant on the qual­ity of the ma­te­ri­als,” Yu said.

From 2007 to 2013, the mar­ket value of global gene ser­vices soared from $8 mil­lion to $4.5 bil­lion, ac­cord­ing to a re­port by BCC Re­search, a tech­nol­ogy mar­ket re­searcher. The fig­ure is pre­dicted to reach $11.7 bil­lion by the end of the year.

In the past decade, the av­er­age cost of a gene test has fallen dra­mat­i­cally as a re­sult of the pop­u­lar­ity of the tech­nol­ogy and the rapidly grow­ing mar­ket, ac­cord­ing to Yu. An NIPT ser­vice costs about 2,500 yuan — 10 times more than a con­ven­tional blood test — but it is not cov­ered by State med­i­cal in­sur­ance

“China is one of the world’s big­gest gene test­ing mar­kets. Last year, only about 20 per­cent of the coun­try’s 20 mil­lion preg­nant women had NIPT, leav­ing great po­ten­tial for fu­ture growth,” Yu said.

“At the same time, many small com­pa­nies have tried to swell prof­its by squeez­ing costs and con­duct­ing tests on sam­ples that didn’t meet stan­dards or by re­duc­ing the amount of DNA be­ing tested.”

He be­lieves gene tech­nol­ogy has prompted sig­nif­i­cant im­prove­ments in the screen­ing for ge­netic dis­eases, can­cer di­ag­no­sis and drug tar­get dis­cov­ery.

“How­ever, healthy mar­ket growth should be guar­an­teed by strong in­dus­try poli­cies, strict laws and reg­u­la­tions, pa­tient-friendly ser­vices and height­ened pub­lic aware­ness. Those fac­tors would help gene test­ing to pro­vide a ma­jor con­tri­bu­tion to peo­ple’s health,” he said.

Con­tact the writer at yang­wanli@ chi­nadaily.com.cn

LIANG LUWEN / FOR CHINA DAILY

PRO­VIDED TO CHINA DAILY

Preg­nant women wait to un­dergo fe­tal heart in­spec­tions at a gy­ne­col­ogy and ob­stet­rics clinic in Nan­jing, cap­i­tal of Jiangsu prov­ince.

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