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Renal Anaemia in the news

Fetal RhCE genotyping from maternal blood highly accurate

• 11 February 2009
• Reuters Health

By David Douglas

NEW YORK (Reuters Health) - Genotyping for RhC/c and RhE/e can be determined noninvasively and reliably using fetal DNA extracted from maternal blood, according to pooled data from published studies, researchers report in the January issue of BJOG.

As lead investigator Dr. Ossie Geifman-Holtzman told Reuters Health, "We demonstrated that fetal RhCE genotyping using fetal DNA obtained from maternal blood achieved an accuracy of up to 100%. Accurate fetal RhCE and fetal RhD genotyping can be performed by using peripheral maternal blood, in a similar manner to blood count and other blood tests."

Dr. Geifman-Holtzman of Temple University, Philadelphia, and colleagues note that the approach is in clinical use in Europe but not in the US.

To review the diagnostic accuracy of fetal RhCE genotyping from maternal blood, they examined data from 20 relevant studies.

Composite estimations showed the overall accuracy to be 96.35% for the fetal RhC/c genotype and 98.2% for RhE/e. When free fetal DNA from maternal plasma was used, rather than fetal-derived cells, the accuracy of RhCE genotyping rose to 100%.

"This method," continued Dr. Geifman-Holtzman, "offers novel, safe, risk-free noninvasive prenatal diagnosis compared with the existing invasive prenatal diagnosis methods that are used in the clinical management of the pregnant patient -- such as amniocentesis or chorionic villus sampling."

"This noninvasive prenatal diagnosis method," he concluded, "also leads the way for an accurate noninvasive prenatal diagnosis of fetal single gene disorders such as cystic fibrosis and aneuploidies, such as Down syndrome."

BJOG 2009;116:144-151.