An ultrasound finding of 2-3 syndactyly is linked to which genetic condition?

The ultrasound finding of 2-3 syndactyly is notably associated with the Syndrome of Laterality (SLO), which involves various forms of congenital malformations related to the body's laterality. In SLO, syndactyly, particularly between the second and third digits, is a characteristic finding. This condition results from disruptions in the normal development of the body's structure, leading to issues such as laterality defects and polydactyly, along with syndactyly.

Other conditions mentioned do not typically link with this specific ultrasound finding. Trisomy 21, also known as Down syndrome, may present with other structural anomalies but does not commonly feature 2-3 syndactyly as a hallmark finding. Short femur does not specifically correlate with syndactyly and pertains more to measurements of skeletal development. Thanatophoric dysplasia is primarily characterized by severe skeletal dysplasia and limb shortening, but it does not typically present with syndactyly.

Thus, the combination of features typical of the Syndrome of Laterality distinctly aligns with the ultrasound finding of 2-3 syndactyly, making it the correct choice in this context.