Prenatal Ultrasound and Genetic Diagnosis of EFTUD2 Haploinsufficiency in Two Fetuses: A Case Series

Abstract: Mandibulofacial dysostosis with microcephaly (MFDM) is caused by haploinsufficiency of EFTUD2 gene. This syndrome is characterized by microcephaly, malar and mandibular hypoplasia, ear abnormalities, developmental delay, and intellectual disability. In this study, we report two cases of fetuses presenting a phenotype consistent with MFDM and confirmed EFTUD2 gene variants. The patients were referred following abnormal ultrasound findings. Genetic diagnostics in both cases revealed heterozygous variants in the EFTUD2 gene that had not been previously reported prenatally. In the first patient, exome sequencing identified a c.2698_2701del p.(Val865Serfs*34), while in the second a novel large deletion involving multiple genes, including the entire EFTUD2 gene, was detected by microarray analysis. Prenatal diagnosis of MFDM requires precise ultrasound assessment. Therefore, consideration of characteristic features observed in fetuses with MFDM is essential for differential diagnosis and guiding targeted genetic testing. Keywords: facial dysostoses, prenatal testing, exome sequencing, microarray