Photo by Nina Matthews
New research suggests expanded prenatal genetic testing may increase the detection of carrier status for potentially serious genetic conditions, including hemoglobinopathies.
Researchers analyzed nearly 350,000 adults of diverse racial and ethnic backgrounds and found evidence to suggest that expanded screening for up to 94 conditions can increase the detection of carrier status when compared with current genetic testing recommendations from professional societies.
Imran S. Haque, PhD, of Counsyl in San Francisco, California, and his colleagues reported these findings in JAMA. The study was funded by Counsyl, a laboratory providing expanded carrier screening.
Genetic testing of prospective parents to detect carriers of specific inherited recessive diseases is part of routine obstetrical practice. The current recommendations are to test for a limited number of individual diseases, in part based on self-reported racial/ethnic background.
Dr Haque and his colleagues wanted to determine if recent advances in genetic testing could facilitate screening for an expanded number of conditions independent of racial/ethnic background.
The researchers analyzed results from expanded carrier screening in 346,790 reproductive-aged individuals, primarily from the US, without known indication for specific genetic testing.
The individuals were tested for carrier status for up to 94 conditions. Tests were offered by clinicians providing reproductive care.
Risk was defined as the probability that a hypothetical fetus created from a random pairing of individuals (within or across 15 self-reported racial/ethnic categories) would be homozygous or compound heterozygous for 2 mutations presumed to cause severe or profound disease.
Severe conditions were defined as those that, if left untreated, cause intellectual disability or a substantially shortened lifespan. Profound conditions were those causing both intellectual disability and a shortened lifespan.
The researchers found that, in most racial/ethnic categories, expanded carrier screening modeled more hypothetical fetuses at risk for severe or profound conditions than did screening based on current professional guidelines.
Overall, relative to expanded carrier screening, guideline-based screening ranged from identifying 6% of hypothetical fetuses affected for East Asian couples to 87% for African or African American couples.
Though this study suggests expanded screening could be beneficial, the researchers said their findings should be confirmed with prospective studies comparing current carrier screening with expanded screening in at-risk populations.
