Odontohypophosphatasia: Abnormal Tooth Development
Odontohypophosphatasia is a milder variant of hypophosphatasia that primarily affects tooth development. Unlike other forms of the condition, it does not have widespread effects on the body. Instead, individuals with odontohypophosphatasia experience abnormal growth and development of their teeth. As a result, children may lose their baby teeth prematurely, while adults may experience the loss of their fully-formed permanent teeth. However, unlike other forms of hypophosphatasia, odontohypophosphatasia does not lead to skeletal malformations. Radiographic and histologic studies conducted on a patient with odontohypophosphatasia revealed no signs of rickets or osteomalacia.
Causes
Hypophosphatasia is believed to be caused by a genetic defect in a specific gene called tissue-nonspecific alkaline phosphatase (TNSALP). This defect leads to low levels of the TNSALP enzyme in the body, resulting in the accumulation of inorganic pyrophosphate. Over time, the buildup of inorganic pyrophosphate disrupts the formation of hydroxyapatite, a major component of bone that contributes to its volume and weight.
Without sufficient hydroxyapatite, children with hypophosphatasia can develop rickets, a condition characterized by weak and soft bones. In adults, hypophosphatasia can cause osteomalacia, a condition in which the bones become fragile and prone to fractures.