Abstract
This is a retrospective cohort study to evaluate phenotype and genotype characteristics of a prenatal and postnatal cohort with upper limb anomalies from January 2007 to December 2021 in one tertiary referral center for Fetal Medicine. All prenatally on ultrasound suspected upper limb anomalies, such as transverse and longitudinal reduction defects, polydactyly, and syndactyly were evaluated. Additionally, children referred to the Congenital Hand team in the same center with upper limb anomalies that were not identified prenatally, were also evaluated separately.
The prenatal group included 199 pregnancies: 64 transverse and 19 longitudinal reduction defects, 103 polydactylies, and 13 cases with syndactyly. The majority of cases with longitudinal reduction defects (n=10, 52.6%), polydactyly (n=62, 60.2%), and syndactyly (n=10, 76.9%) were non-isolated, as opposed to transverse reduction defects which were generally isolated (n=41, 64.1%). The Congenital Hand Team received 362 new referrals of children with upper limb anomalies that were not identified prenatally. These cases included 49 transverse and 22 longitudinal reduction defects, 226 polydactylies, and 65 syndactlylies. A chromosomal or monogenic abnormality was identified in 76/199 (38.2%) cases of the prenatal group and in 31/362 (8.6%) cases of the postnatal group.
Prenatal identification of minor defects of the digits holds a challenge, since we observed more postnatal than prenatal cases. The majority of cases with isolated anomalies in both groups had no underlying chromosomal, monogenic or syndromic cause, as compared to the non-isolated cases. Conducting structural anomaly scans and genetic counselling are crucial to assess the risk of genetic abnormalities.