Ultrasound Phenotype, Genetic Analysis, and Pregnancy Outcomes of Fetuses With 1p36 Deletion Syndrome.

Background: The intrauterine ultrasound phenotype, genotype, pregnancy outcome, and neonatal prognosis of fetuses with 1p36 deletion syndrome were retrospectively analyzed, as previous reports are limited.

Methods: Pregnant women (25,000) who underwent interventional prenatal diagnosis between December 2016 and March 2024 were selected. Fetal villus tissue, amniotic fluid, or umbilical cord blood were extracted for single nucleotide polymorphism array (SNP-array) detection under ultrasound guidance.

Results: Thirteen fetuses had 1p36 deletions involving fragments that were 0.46-22.5 Mb. Six and seven fetuses had large and small copy number variation (CNV) fragment deletions in the 1p36 region, respectively. Two fetuses had normal ultrasound phenotypes, three underwent early spontaneous abortion, one had isolated ventricular septal defect, one had isolated mild ventriculomegaly, two had mild ventriculomegaly associated with increased renal echogenicity, one had mild ventriculomegaly associated with ventricular septal defect, one had severe ventriculomegaly associated with ventricular septal defect and fetal growth restriction, one had tricuspid valve dysplasia, and one had nasal bone dysplasia. Three 1p36 deletions were de novo, and one was paternally inherited. There were three cases of early spontaneous abortion, seven terminations, and three routine postnatal follow-ups.

Conclusions: High-resolution SNP-arrays are suitable for the prenatal diagnosis of 1p36 deletion syndrome.