Prenatal Sonographic Features of Heterozygous DLL1 Single-Nucleotide Variants and 6q27 Deletions: A Single Referral Center Retrospective Case Series.

Objective

To present the prenatal sonographic features and genomic spectrum of pregnancies with fetuses with a DLL1 single-nucleotide variant (SNV) or a pure 6q27 deletion.

Methods

This was a retrospective study of 20 cases with a DLL1 SNV or a pure 6q27 deletion diagnosed by prenatal genetic testing. Clinical and laboratory data were collected and reviewed for these cases, including maternal demographics, prenatal sonographic findings, molecular testing results, and pregnancy outcomes.

Results

One case was diagnosed in the first trimester due to increased nuchal translucency. Thirteen cases received diagnoses in the second trimester: one resulted from abnormal non-invasive prenatal testing, one had isolated cerebellar hypoplasia, six involving isolated ventriculomegaly, and five attributed to non-isolated ventriculomegaly. Six additional cases were diagnosed in the third trimester. Copy number variations involving deletions of DLL1 were identified in 10 cases, and SNVs of DLL1 were found in an additional 10 cases.

Conclusion

Our study highlights that even nonspecific findings of central nervous system on prenatal ultrasound may justify exome sequencing.