NCT02237625 · Duke University
Natural History Study of Patients With Hypophosphatasia (HPP)
(NatHisHPP)
What this study is about
Hypophosphatasia (HPP) is a rare inherited metabolic disorder characterized by defective bone and teeth mineralization caused by mutations of the ALPL gene, which encodes for the tissue-nonspecific alkaline phosphatase (TNSALP) isozyme, resulting in decreased serum and bone alkaline phosphatase levels. To date, over 250 different mutations in the gene encoding TNSALP have been associated with HPP.
View original scientific description
Hypophosphatasia (HPP) is a rare inherited metabolic disorder characterized by defective bone and teeth mineralization caused by mutations of the ALPL gene, which encodes for the tissue-nonspecific alkaline phosphatase (TNSALP) isozyme, resulting in decreased serum and bone alkaline phosphatase levels. To date, over 250 different mutations in the gene encoding TNSALP have been associated with HPP. Clinically, the loss of TNSALP function results in progressive skeletal impact as well as progressive impact on all other major organ systems. It clinically manifests as rickets in infants and children and osteomalacia at all ages. The severe form of the disease has been estimated to have a prevalence of about 1 in every 100,000 live births.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patients or their legal representative must provide written informed consent or, if applicable, qualify for waiver of consent.
- Patients must have a pre-established clinical diagnosis of HPP, as indicated by one or more of the following:
- Serum alkaline phosphatase (ALP) below the age-adjusted normal range
- Plasma PLP at least twice the upper limit of normal (no vitamin B6 administered for at least 1 week prior to determination)
- Evidence of osteopenia or osteomalacia on skeletal radiographs
- Genetic analysis fof the ALPL gene
- Must be current patient in the Duke University System.
Exclusion criteria
- Any patient without confirmation of clinical diagnosis of HPP.
Where
- Durham, North Carolina
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Mar 5, 2026 · Source of record for eligibility and locations