Retrospective, Non-interventional Natural History of Patients With Juvenile-onset Hypophosphatasia (HPP)

Hypophosphatasia (HPP) is a life-threatening, genetic, and ultra-rare metabolic disease
characterized by defective bone mineralization and impaired phosphate and calcium regulation
that can lead to progressive damage to multiple vital organs, including destruction and
deformity of bones, profound muscle weakness, seizures, impaired renal function, and
respiratory failure. There are no approved disease-modifying treatments for patients with
this disease. There is also limited data available on the natural course of this disease
over time, particularly in patients with the juvenile-onset form.

Inclusion Criteria:

- Documented informed consent unless patient is deceased

- Patients with Juvenile-onset HPP, defined as documented onset of first signs/symptoms
at ≥ 6 months to ˂18 years

- Documented diagnosis of HPP as indicated by skeletal manifestations and low alkaline
phosphatase or genotyping

Exclusion Criteria:

- Received treatment with asfotase alfa in the ENB-006-09 study and/or currently
enrolled in the ENB-008-10 study

- Received other treatment and/or intervention to treat HPP up to 15 years old

- Other clinically significant disease