Prenatal microarray comparative genomic hybridization: Experience from the two first years of activity at the Lyon university-hospital.

OBJECTIVES: This study aims to describe how microarray comparative genomic hybridization (aCGH) has shifted to become a prenatal diagnosis tool at the Lyon university-hospital.

MATERIALS AND METHODS: This retrospective study included all patients who were referred in the 3 pluridisciplinary centers for prenatal diagnosis of the Lyon university-hospital and who received a prenatal aCGH between June 2013 and June 2015. aCGH was systematically performed in parallel with a karyotype, using the PréCytoNEM array design.

RESULTS: A total of 260 microarrays were performed for the following indications: 249 abnormal ultrasounds (95.8%), 7 characterizations of chromosomal rearrangements (2.7%), and 4 twins with no abnormal ultrasounds (1.5%). With a resolution of 1 mega base, we found 235 normal results (90.4%), 23 abnormal results (8.8%) and 2 non-returns (0.8%). For the chromosomal rearrangements visible on the karyotype, aCGH identified all of the 12 unbalanced rearrangements and did not identify the 2 balanced rearrangements. Among the fetuses with normal karyotypes, 11 showed abnormal microarray results, corresponding to unbalanced cryptic chromosomal rearrangements (4.2%).

CONCLUSION: Transferring aCGH to a prenatal diagnosis at the Lyon university-hospital has increased the detection rate of chromosomal abnormalities by 4.2% compared to the single karyotype.