Prenatal isolated clubfoot increases the risk for clinically significant exome sequencing results.

OBJECTIVE: To examine the diagnostic yield of exome sequencing (ES) in singleton pregnancies with isolated fetal clubfoot. METHODS: Clinical data from singleton pregnancies with a sonographic diagnosis of isolated clubfoot and ES results between 2018 and 2021 were retrospectively obtained from a single referral medical center. The recorded data include maternal age, gestational age at sonographic diagnosis, the indication for genetic testing, ES results, and pregnancy outcomes. RESULTS: During the study period, 38 fetuses were prenatally diagnosed with isolated clubfoot by ultrasound and underwent ES after the copy number variant analysis was non-diagnostic. Through the trio-ES analysis, pathogenic or likely pathogenic variants were detected in 4 of 38 (10.5%) with the following genes: BRPF1, ANKRD17, FLNA, and KIF1A. All are de novo with three of autosomal dominant inheritance and one of X-linked recessive inheritance. CONCLUSION: Sonographic diagnosis of clubfoot, even isolated, increases the risk for monogenic syndromes. Exome sequencing should be an option for genetic investigation for such pregnancies.