Objectives: Freeman-Sheldon syndrome (FSS) is a rare genetic condition with facial and joint abnormalities. Here we report the first case of prenatal diagnosis in a fetus with negative familial history for this syndrome. A chart of the fetal mouth length was generated and its usefulness verified.
Methods: A cross-sectional study was carried out to derive standard charts for fetal lip lengths. The study population was made up of 371 fetuses between 15 and 38 weeks of gestation examined only once for this purpose. A statistical analysis previously recommended to derive normal ranges in fetal growth charts was employed.
Results: A 34-year-old woman was referred at 28 weeks of gestation for polyhydramnios and clubfeet. A detailed scan confirmed those findings and showed joint contractures of hands, a severe microstomia with a 'whistling' mouth, and an H-shaped mark over the chin. FSS was suspected, though there was no family history for this genetic syndrome. After emergency delivery at 32 weeks, the syndrome was confirmed. The infant died two months later from pneumonia. Upon construction of a standard mouth length chart, it was found that the fetal lip width in this case of FSS was well below the 5th centile.
Conclusion: Here we present a standard chart for fetal lip width. We demonstrated its usefulness in cases with fetal face anomalies. Specific charts are fundamental for an objective assessment of the fetal parameters.