Commonest congenital deformity is
**Core Concept**
The question is testing knowledge of the most prevalent congenital anomaly, which is a structural or functional defect present at birth. Congenital deformities can affect various systems, including the musculoskeletal, cardiovascular, and nervous systems.
**Why the Correct Answer is Right**
The correct answer is Polydactyly, which is a congenital condition characterized by the presence of extra fingers or toes. This condition occurs due to genetic mutations during embryonic development, specifically in the formation of the limb buds. The genetic factors involve mutations in genes such as BMP2, BMP4, and PITX1, which regulate the expression of other genes involved in limb development.
**Why Each Wrong Option is Incorrect**
* **Option A:** Clubfoot is a congenital deformity, but it is not the most common. It is a condition where the foot is twisted inward, often requiring surgical correction.
* **Option B:** Cleft lip and palate are congenital anomalies, but they are relatively rare compared to polydactyly. They occur due to genetic and environmental factors during embryonic development.
* **Option C:** Neural tube defects, such as spina bifida, are congenital anomalies, but they are not as common as polydactyly. They occur due to a failure of the neural tube to close during embryonic development.
**Clinical Pearl / High-Yield Fact**
Polydactyly can be inherited in an autosomal dominant pattern, and it is more common in individuals with certain genetic syndromes, such as Greig cephalopolysyndactyly syndrome. It is essential to recognize polydactyly as a common congenital deformity to provide early diagnosis and management.
**Correct Answer: C. Polydactyly**