Table 1.

Subtypes and clinical features of HPP

HPP forms	Prevalence	Transmission	Age at onset	Clinical features
Severe	1:300,000	Autosomal recessive	Perinatal, Infant	Severe bone mineralization deficiency with bowing of limbs, small chest, pulmonary hypoplasia, and muscle weakness resulting in the need for ventilator support Neurological involvement including irritability and pyridoxine-dependent seizures
Moderate	1:2430	Autosomal recessive or autosomal dominant	Child, Adult	Rickets, fractures, short stature and poor mobility Craniosynostosis and increased intracranial pressure Premature loss of deciduous teeth Premature loss of primary and secondary teeth with intact roots in adults Musculoskeletal pains Fragility fractures Chondrocalcinosis and pseudogout
Mild	1:508	Autosomal dominant	Adult	Arthromyalgia Microcrystal arthropathy Fragility fractures in adulthood