Atypical Prenatal Phenotypic Spectrum: A Case Series of Four Unique Presentations With Genetic and Diagnostic...

Prenatal diagnosis of genetic syndromes often relies on structural anomalies; however, many monogenic disorders show atypical or evolving prenatal phenotypes, limiting imaging-based diagnosis. We report four fetuses with atypical presentations diagnosed by exome/genome sequencing. Pathogenic variants were identified in BBS1, SLC26A2, POMT2, and COL25A1. Prenatal findings included heterotaxy with complex heart disease, isolated long bone shortening, subtle CNS anomalies, and recurrent contractures. These cases highlight the variability in the prenatal phenotypic spectrum of genetic disorders and the value of genomic sequencing for accurate genetic counseling and reproductive decision-making.