Prader‐Willi syndrome (PWS) is a complex neuro‐genetic disorder with estimated prevalence varying from 1 in 10,000 to 1 in 30,000 with an equal number of males and females affected. A study of the incidence of PWS in France reported thirty‐eight infants were diagnosed at a median age of 18 days post birth. None of the cases were identified prenatally. The condition is complex with fetal PWS phenotype including fetal hypo‐mobility, polyhydramnios, intra‐uterine growth restriction, and immobile flexed extremities with clenched hands or fists, symptoms which are not exclusively pathognomonic to PWS.
Reissland, N., Makhmud, A., & Froggatt, S. (2019). Comparing a foetus diagnosed with Prader–Willi syndrome with non-affected foetuses during light and sound stimulation using 4D ultrasound. Acta Paediatrica: Nurturing the Child, 108(2), 375-376. https://doi.org/10.1111/apa.14622