Prenatal ultrasound findings in Koolen-de Vries foetuses: Central nervous system anomalies are frequent markers of this syndrome.

Objective: Prenatal diagnoses of microdeletion syndromes without ultrasound findings in the first and second trimester are always difficult. The objective of this study is to report the prenatal ultrasound findings in four foetuses diagnosed with 17q21.31 microdeletions (Koolen-de Vries syndrome) using chromosomal microarrays (CMA).