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Test could screen for more than 400 childhood diseases

Jan. 12, 2011
Courtesy of Sci­ence Transla­t­ional Med­i­cine
and World Science staff

A new ge­net­ic test could be used rou­tinely by doc­tors to screen for 448 se­vere child­hood dis­eases in cou­ples be­fore they have chil­dren, ac­cord­ing to a stu­dy. 

The test checks for re­ces­sive dis­eases—conditions caused by muta­t­ions that gen­er­ally don’t af­fect the par­ents but can af­fect their chil­dren if both par­ents are car­ri­ers. The test is de­signed to tell par­ents whe­ther this risk exists.

Com­bined with ge­net­ic coun­sel­ing, the tech­nol­o­gy may re­duce the in­ci­dence of se­vere re­ces­sive child­hood dis­eases and help speed up di­ag­no­sis of these dis­or­ders in new­borns, re­search­ers said.

But sci­en­tists al­so fret that the psy­cho­log­i­cal bur­den of such a test, along with oth­er is­sues re­lat­ed to the dy­nam­ics of re­pro­duc­tion, will need to be thor­oughly ad­dressed be­fore pre­con­cep­tion screen­ing is avail­a­ble to the gen­er­al pub­lic. 

In­her­it­ed child­hood dis­eases as a whole ac­count for about one in five in­fant deaths and one in 10 child hos­pi­tal­iz­a­tions, ac­cord­ing to the re­search­ers, who re­ported their pre­lim­i­nar­y find­ings in the Jan. 12 is­sue of the re­search jour­nal Sci­ence Transla­t­ional Med­i­cine.

In the last few dec­ades, over a thou­sand genes im­pli­cat­ed in these dis­eases have been iden­ti­fied, yet pre­con­cep­tion screen­ing for cou­ples in the Un­ited States is only rec­om­mended for five dis­eases in spe­cif­ic popula­t­ions. These con­di­tions in­clude frag­ile X syn­drome, cyst­ic fi­bro­sis, and Tay-Sachs dis­ease.

Now, Ste­phen Kingsmore at the Na­tional Cen­ter for Ge­nome Re­sources in San­ta Fe, N.M. and col­leagues have de­vel­oped a pre­con­cep­tion car­ri­er test ca­pa­ble of screen­ing sev­er­al hun­dred DNA sam­ples sim­ul­ta­ne­ously for 448 re­ces­sively in­her­it­ed child­hood dis­eases. 

The test is based on a com­bina­t­ion of tech­niques, in­clud­ing “next-genera­t­ion” gene se­quenc­ing, the sci­en­tists said. Us­ing the new sysytem to screen around 100 un­re­lat­ed peo­ple, they found that on av­er­age, each per­son tested har­bored two to three se­vere child­hood dis­ease muta­t­ions. They al­so disco­vered that about 10 per­cent of dis­ease muta­t­ions in com­monly used databases are in­cor­rect, sug­gest­ing, they said, that dis­ease muta­t­ion databases need care­ful scru­ti­ny.

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A new genetic test could be used routinely by doctors to screen for 448 severe childhood diseases in couples before they have children, according to a study. The test checks for recessive diseases—conditions caused by mutations that generally don’t affect the parents but could affect their children if both parents are carriers. Combined with genetic counseling, the technology may reduce the incidence of severe recessive childhood diseases and help to speed up diagnosis of these disorders in newborns, researchers said. But scientists also fret that the psychological burden of such a test, along with other issues related to the dynamics of reproduction, will need to be thoroughly addressed before preconception screening is available to the general public. Inherited childhood diseases as a whole account for about one in five infant deaths and one in 10 child hospitalizations, according to the researchers, who reported their preliminary findings in the Jan. 12 issue of the research journal Science Translational Medicine. In the last few decades, over a thousand genes implicated in these diseases have been identified, yet preconception screening for couples in the United States is only recommended for five diseases in specific populations, including fragile X syndrome, cystic fibrosis, and Tay-Sachs disease. Now, Stephen Kingsmore at the National Center for Genome Resources in Santa Fe, N.M. and colleagues have developed a preconception carrier test capable of screening several hundred DNA samples simultaneously for 448 recessively inherited childhood diseases. The test is based on a combination of techniques, including “next-generation” gene sequencing, the scientists said. Using the new sysytem to screen around 100 unrelated people, they found that on average, each person tested harbored two to three severe childhood disease mutations. They also discovered that about 10 percent of disease mutations in commonly used databases are incorrect, suggesting, they said, that disease mutation databases need careful scrutiny.