Yaying Cheng

Abstract Background: Beckwith-Wiedemann syndrome (BWS) is an overgrowth disorder primarily caused by imprinting defects at 11p15.5. Mosaic paternal uniparental disomy (pUPD) accounts for approximately 20% of cases but is challenging to detect prenatally using routine low-coverage CNV-seq, as this approach has limited sensitivity for copy-number-neutral events such as uniparental disomy, particularly when present in a mosaic state.

1 Introduction Intrauterine growth restriction (IUGR), describes impaired fetal growth caused by pathological mechanisms. The precise etiology remains multifactorial, with established contributors including maternal conditions, umbilical cord abnormalities, fetal genetic defects, and placental dysfunction [1]. Notably, placental insufficiency constitutes the predominant pathogenic mechanism.