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Updated: Feb 8, 2026

Nanosensors to Detect Protease Activity In Vivo for Noninvasive Diagnostics
Published on: July 16, 2018
Noninvasive Prenatal Testing: Comparison of Two Mappers and Influence in the Diagnostic Yield
Irene Gómez-Manjón1, Ana Moreno-Izquierdo1,2, Sonia Mayo1
1Genetics and Inheritance Research Group, Instituto de Investigación Hospital Universitario 12 de Octubre (i+12), Avda. de Córdoba s/n, Madrid 28041, Spain.
Objective:
The aim of this study was to determine if the use of different mappers for NIPT may vary the results considerably.
Methods:
Peripheral blood was collected from 217 pregnant women, 58 pathological (34 pregnancies with trisomy 21, 18 with trisomy 18, and 6 with trisomy 13) and 159 euploid. MPS was performed following a manufacturer's modified protocol of semiconductor sequencing. Obtained reads were mapped with two different software programs: TMAP and HPG-Aligner, comparing the results.
Results:
Using TMAP, 57 pathological samples were correctly detected (sensitivity 98.28%, specificity 93.08%): 33 samples as trisomy 21 (sensitivity 97.06%, specificity 99.45%), 16 as trisomy 18 (sensibility 88.89%, specificity 93.97%), and 6 as trisomy 13 (sensibility 100%, specificity 100%). 11 false positives, 1 false negative, and 2 samples incorrectly identified were obtained. Using HPG-Aligner, all the 58 pathological samples were correctly identified (sensibility 100%, specificity 96.86%): 34 as trisomy 21 (sensibility 100%, specificity 98.91%), 18 as trisomy 18 (sensibility 100%, specificity 98.99%), and 6 as trisomy 13 (sensibility 100%, specificity 99.53%). 5 false positives were obtained.
Conclusion:
Different mappers use slightly different algorithms, so the use of one mapper or another with the same batch file can provide different results.
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