Chromosomal Microarray Analysis versus Karyotyping in Fetuses with Increased Nuchal Translucency

Abstract

We have carried out a retrospective study of chromosome anomalies associated with increased nuchal translucency (NT) in order to compare yield rates of karyotype, chromosome microarray analysis (CMA), and non-invasive prenatal testing (NIPT) in this condition. Presenting with increased NT or cystic hygroma ≥3.5 mm as an isolated sign, 249 fetuses underwent karyotype and/or CMA from 11 to 18 gestational weeks. Karyotype and fluorescence in situ hybridization (FISH) analyses detected 103 chromosomal anomalies including 95 aneuploidies and eight chromosomal rearrangements or derivatives. Further, seven pathogenic copy number variants (CNV), five likely pathogenic CNVs, and 15 variants of unknown significance (VOUS) were detected by CMA in fetuses with normal karyotype. Genetic testing is now facing new challenges due to results with uncertain clinical impacts. Additional investigations will be necessary to interpret these findings. More than 15% of the anomalies that we have diagnosed with invasive techniques could not be detected by NIPT. It is therefore definitely not recommended in the case of ultrasound anomalies. These results, while corroborating the use of CMA in fetuses with increased NT as a second tier after rapid aneuploidy testing, do not suggest a dismissal of karyotype analysis.

The difference between karyotype analysis and chromosome microarray for mosaicism of aneuploid chromosomes in prenatal diagnosis

“…CMA can detect micro‐deletions and micro‐duplications of chromosomes, but cannot detect balanced structural abnormalities, such as balanced translocation and inversion of chromosomes. Therefore, clinics often combine the two methods for prenatal diagnosis 9 …”

“…Therefore, clinics often combine the two methods for prenatal diagnosis. 9 Karyotype and CMA analysis can both detect aneuploid chromosomes. However, differences between the two methods may lead to different results in the diagnosis of aneuploid chromosomes.…”

Epidemiology of fetal cerebral ventriculomegaly and evaluation of chromosomal microarray analysis versus karyotyping for prenatal diagnosis in a Chinese hospital

“…Although the sample size for microarray analysis ( n = 114) was too small to draw any final conclusions, these current results indicate that microarray analysis is equivalent to standard karyotype analysis for prenatal diagnosis and improves the detection of clinically relevant findings. Besides identification of fetuses with trisomy 8, 13, 18, 21, a sex chromosome aneuploidy, or triploidy, 4,20 rearrangements of 1p36, 21,22 1q21.1, 7q11, 16p11.2, 16p13.3, 1,23 and other de novo mutations were also detected. All the detected rearrangements in this current study were considered to be disease-related alterations that cannot be completely excluded during genetic counselling.…”

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“…La ubicación más frecuente es a nivel cervical y se puede asociar a síndromes genéticos y anormalidades cromosómicas (Schreurs et al, 2018). El diagnóstico del higroma quístico se hace a través de la ultrasonografía midiendo la translucencia nucal fetal en el primer trimestre del embarazo (Cicatiello et al, 2019). Como exámenes complementarios, tenemos el análisis de cariotipo y el microarray cromosómico para confirmar la presencia o ausencia de aneuploidías (Schreurs et al, 2018;Cicatiello et al, 2019).…”