Clinical utility of noninvasive fetal trisomy (NIFTY) test – early experience

Abstract

Objective: To report the initial experience of noninvasive prenatal diagnosis of fetal Down syndrome (The NIFTY test) in a clinical setting. Methods: The NIFTY test was offered as a screening test for fetal Down syndrome to pregnant women with a singleton pregnancy at 12 weeks of gestation or beyond. A satisfaction questionnaire was sent to the first 400 patients. Results: During a 6-month period, 567 NIFTY tests were performed. Over 90% of those studied were ethnic Chinese, and the mean age of the women studied was 36 years. The test was performed at 12–13 weeks of gestation in 49.21%. The median reporting time was 9 days. The test was positive for trisomy 21 in eight cases, and for trisomy 18 in 1 case; all were confirmed by fetal karyotyping. There was no false-positive result. Of the questionnaires, 182 completed responses were received. Over 95% had complete or almost complete resolution of anxiety. Except for one, all were satisfied with the NIFTY test, and all indicated that they would recommend the test to their friends. Conclusion: The NIFTY test was a highly specific test. Unnecessary invasive tests and associated fetal losses could be avoided in almost all women who have a normal fetus.

Systematic review of noninvasive prenatal diagnosis for abnormal chromosome genetic diseases using free fetal DNA in maternal plasma

“…Four studies in total were selected for analysis. Lau et al (2012) recently conducted noninvasive prenatal diagnosis of 567 high-risk gravida. Eight Down syndrome patients and 1 Edwards syndrome patient were diagnosed, which were found to be false-positive and false-negative by karyotyping.…”

Successful Noninvasive Trisomy 18 Detection Using Single Molecule Sequencing

“…With the use of massively parallel sequencing (MPS) 4 and subsequent quantification of chromosome-specific sequences, overrepresentation of a specific chromosome can be determined with high diagnostic accuracy. Successful detection of fetal trisomy 21 in maternal plasma was shown in several clinical validation studies (3)(4)(5)(6)(7). For noninvasive detection of trisomy 18 (Edwards syndrome) and trisomy 13 (Patau syndrome), however, it seems to be more difficult to achieve similar results (7)(8)(9)(10).…”

Chroniques génomiques

“…Pour ce faire, l'ADN isolé à partir de quelques millilitres de sang maternel est séquencé de manière relativement superficielle (à une redondance nettement inférieure à 1), et l'on compte le nombre de fois où des séquences spécifiques du chromosome 21 sont retrouvées, sans tenter de distinguer ce qui provient de la mère ou du foetus. Bien que l'ADN maternel représente de 80 à 95 % de l'échantillon, il s'avère que la petite augmentation de la représentation du chromosome 21 due à la trisomie de l'embryon peut être détectée de manière fiable [4,5] …”