Can Prenatal Ultrasound and Genetic Testing Reliably Exclude Non-Isolated Clubfoot?

The aim of this study is to evaluate the efficacy of prenatal second trimester ultrasound in diagnosing isolated congenital clubfoot and to assess the role of prenatal genetic testing.

We conducted a retrospective cohort study in the North-West region of the Netherlands with prenatally suspected clubfoot between 16 and 24 weeks of gestation from 2007 to 2021. We included isolated cases, defined as no additional structural anomalies on the initial targeted ultrasound. Rapid aneuploidy testing, chromosomal microarray analysis, and/or exome sequencing were performed via invasive testing following on parental request.

We identified 423 cases of isolated clubfoot. The diagnosis changed to prenatal non-isolated clubfoot during prenatal follow-up in 20 cases (5%); in 10 cases during a follow-up ultrasound, and in 10 cases, an underlying genetic condition was found. In 11 cases, the initial suspicion of clubfoot was not confirmed at follow-up ultrasound. There were 387 ongoing pregnancies with a prenatal diagnosis of isolated clubfoot. In 47 children (12%), diagnosis changed postnatally to non-isolated. These postnatal findings were classified as major in 36 children (9%). In 40 cases (10%), the prenatal diagnosis of clubfoot was not confirmed postnatally.

Prenatal ultrasound combined with genetic testing are components in the work-up of clubfoot, enabling the identification of associated structural anomalies and underlying genetic disorders. Despite advances in prenatal ultrasound and genetic testing, distinguishing isolated clubfoot from cases with additional structural or genetic anomalies remains challenging. Moreover, prenatal genetic testing does not exclude the absence of structural or neurodevelopmental issues diagnosed after birth.