Which are the symptoms of Hypophosphatasia?

Hypophosphatasia is a rare genetic disorder characterized by the defective mineralization of bones and teeth due to low levels of alkaline phosphatase (ALP). Symptoms range widely from life-threatening respiratory failure and seizures in newborns to chronic bone pain, recurrent fractures, and premature tooth loss in adults.

What are the primary symptoms of Hypophosphatasia?

The clinical presentation of Hypophosphatasia is highly variable, largely depending on the age of onset. The disease is caused by mutations in the ALPL gene, which leads to an accumulation of substrates that inhibit bone mineralization. In infants, the most severe form often presents with failure to thrive, hypercalcemia, and respiratory complications due to a soft rib cage. In children and adults, Hypophosphatasia typically manifests as skeletal abnormalities, including bowed legs (rickets), delayed walking, and persistent musculoskeletal pain. A hallmark sign across many age groups is the premature loss of primary (baby) teeth, often occurring before age five, because the roots fail to anchor properly in the jawbone.

What are the early warning signs to watch for?

Early identification of Hypophosphatasia is crucial for managing long-term skeletal health. Parents and clinicians should look for the following clinical indicators:

• Dental anomalies: Early shedding of primary teeth, specifically incisors, without the presence of inflammation or gum disease.


• Skeletal development: Delayed gross motor milestones, such as late walking, or a waddling gait.


• Bone health: Recurrent or "stress" fractures that occur after minor trauma, or unexplained bone and joint pain.


• Metabolic markers: Unexplained low serum alkaline phosphatase levels on routine blood work, which is the most consistent biochemical indicator of Hypophosphatasia.

How does disease severity vary between patients?

The severity of Hypophosphatasia exists on a spectrum. Perinatal and infantile forms are the most severe, often involving severe skeletal hypomineralization and high mortality rates. Conversely, the childhood and adult forms of Hypophosphatasia are generally milder but cause significant morbidity. Patients with the adult-onset form may live for decades with only minor symptoms, such as recurring foot pain or early tooth loss, while others experience debilitating chronic pain, muscle weakness, and early-onset osteoarthritis. Because the 9 individuals currently in the DiseaseMaps.org community have reported varying experiences, it is clear that individual clinical monitoring is essential to track how the disease impacts specific bone sites.

When should I seek immediate medical attention?

Immediate medical consultation is required if a patient with Hypophosphatasia experiences sudden, severe bone pain, signs of a fracture, or neurological symptoms such as seizures. In infants, respiratory distress or persistent vomiting—which may indicate hypercalcemia (high blood calcium levels)—requires urgent intervention. Over time, symptoms of Hypophosphatasia may progress, particularly as bone strength diminishes, leading to an increased risk of pseudofractures or complete fractures that fail to heal properly without medical management.

Next steps

• Consult a metabolic bone specialist or a pediatric endocrinologist to confirm a diagnosis through genetic testing and ALP monitoring.


• Request a referral to a dentist or orthodontist familiar with the unique dental manifestations of this condition.


• Connect with the 9 other members on DiseaseMaps.org to share coping strategies for managing chronic pain and physical limitations.


• Maintain a detailed log of bone pain and physical function to discuss with your healthcare team during routine check-ups.

Medical disclaimer: This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Hypophosphatasia.


• Orphanet: Hypophosphatasia (ORPHA:417).


• Online Mendelian Inheritance in Man (OMIM): #241500 (Hypophosphatasia).


• The Hypophosphatasia Foundation (hypophosphatasia.com).