Maternal uniparental disomy for chromosome 6 in 2 prenatal cases with IUGR: case report and literature review

Background Uniparental disomy (UPD) is a rare genetic condition leading to potential disease risks. Maternal UPD of chromosome 6 upd(6)mat is exceptionally rare, with limited cases reported. This study reported two new cases of upd(6)mat and reviewed the literature of previous cases. Case presentation Both cases exhibited intrauterine growth restriction (IUGR), and genetic analysis confirmed upd(6)mat in each case. The literature review identified a total of 19 cases. IUGR and preterm labor were the most common two symptoms observed, and additional anomalies and genetic variations were also reported in some cases. Conclusion upd(6)mat is potentially associatied with IUGR, but the precise genotype–phenotype relationship remains unclear. The cases with upd(6)mat may present clinical features due to imprinting disorders.