First clinical sign of hypophosphatasia:

Infants demonstrate bowed limb bones and a marked deficiency of skull ossification. Individuals with milder forms of the disease show poor growth and deformities similar to rickets. There may be a history of fractures, delayed walking, or bone pain. Approximately 85% of these children show premature loss of the primary teeth, particularly the incisors, and delayed eruption of the permanent dentition. Dental findings are often the first clinical sign of hypophosphatasia and the only sign of odontohypophosphatasia.