Which skeletal feature is characteristic of Hypophosphatasia?

Hypophosphatasia is a genetic disorder characterized by a deficiency of alkaline phosphatase, which plays a crucial role in phosphate metabolism and bone mineralization. The condition leads to hypomineralization of bone and/or teeth because the lack of alkaline phosphatase results in insufficient mineralization of the skeletal structure. This lack of mineralization weakens bones and can result in various skeletal anomalies, making hypomineralization one of the most prominent features of this disorder.

The other options present features that are not characteristic of hypophosphatasia. For example, cleft palate is not commonly associated with this condition, as hypophosphatasia primarily affects bone and teeth rather than soft tissue structures involved in craniofacial development. Short proximal long bones can occur in other skeletal dysplasias but are not a defining feature of hypophosphatasia. Similarly, a narrow thorax is associated with conditions such as achondroplasia or various syndromes but is not a characteristic skeletal feature of hypophosphatasia. Therefore, the hypomineralization of bone and teeth stands out as the defining feature of this disorder.