Hypophosphatasia

What are the signs and symptoms of hypophosphatasia? 

The symptoms of hypophosphatasia can vary widely. In some children, the condition causes mild symptoms. The mildest form of hypophosphatasia is called odontohypophosphatasia. Children with this type may lose their teeth early or have irregular tooth development, but they don’t have any other skeletal problems. 

In other children, hypophosphatasia can be severe or life-threatening.

The most severe types of hypophosphatasia usually cause symptoms before birth or in infancy. Babies may experience:

• Breathing problems
• Difficulty feeding
• Hypercalcemia, or high calcium in the blood
• Irregularly shaped chest
• Multiple broken bones
• Slow weight gain
• Short limbs
• Soft skull bones

When hypophosphatasia symptoms develop later in childhood or adulthood, they’re usually less severe and may include: 

• Bone softening (osteomalacia)
• Enlarged wrists and ankles
• Irregular skull shape
• Joint pain
• Losing baby teeth early
• Recurrent broken bones
• Short stature with knock knees or bowed legs  

How do we diagnose hypophosphatasia? 

We sometimes see signs of hypophosphatasia during a prenatal ultrasound. Your doctor may order additional imaging, such as a fetal MRI, to better evaluate your developing baby.

Your provider may also recommend further testing options such as:

• Blood testing of one or both parents to look for gene mutations.
• Chorionic villus sampling (CVS), which tests cells from your placenta for the gene mutation. We usually perform this test in the first trimester.
• Amniocentesis to test amniotic fluid (the protective liquid surrounding your baby) for the gene mutation. We usually perform this test after the second trimester has started.

In other cases, doctors diagnose diastrophic dysplasia after your baby is born or during early childhood based on symptoms. Your child may have additional tests such as:

• Tests to look at the collagen gene that can be obtained from blood, spit or cheek swabs
• X-rays to get a clear picture of their skeleton

If your child has hypophosphatasia symptoms, their doctor may use blood tests for ALP levels to confirm the diagnosis. Your child may also have a blood test that checks for a mutation in the ALPL gene.

How do we treat hypophosphatasia? 

Most children with hypophosphatasia take an injectable medication called asfotase alfa (Strensiq®). This drug replaces ALP to help make bones stronger.

Your child’s doctor may recommend additional hypophosphatasia treatments, such as:

• Dental care to treat tooth problems
• Injections of calcitonin, a hormone that helps lower or regulate calcium levels
• Nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce bone or joint pain
• Occupational therapy to improve fine motor skills
• Orthotic devices, such as special shoe inserts or boots, to help improve alignment and gait
• Physical therapy to increase strength and mobility
• Surgery to place a metal rod inside a bone that continues breaking easily

Why choose us for treatment of hypophosphatasia? 

At Children’s Hospital Colorado, we provide advanced, compassionate care for children with hypophosphatasia. Our team offers state-of-the-art testing, accurate diagnoses and effective treatments. We offer:

• Coordinated, leading-edge care: At Children’s Colorado, we’re setting the standard for pediatric orthopedic care. We are one of only a few children’s hospitals in the country that offers all the necessary care for hypophosphatasia in one place, including pediatric orthopedics and rehabilitation medicine. Children with skeletal dysplasia receive all the care they need in our multidisciplinary care center, so you don’t have to travel to see many specialists.
• Full-spectrum care: The Colorado Fetal Care Center offers comprehensive genetic testing and state-of-the-art imaging to accurately diagnose genetic diseases such as hypophosphatasia before babies are born. After birth, your child receives care through childhood and beyond in our Skeletal Health and Dysplasia Program. We help you understand your child’s health and all the treatment options. As a part of this program, doctors from endocrinology oversee the administration of medicines to strengthen the bones.
• Treatment from experts: Our highly specialized orthopedic team has experience in the rarest and most complex injuries and conditions. In fact, our orthopedic surgery team is among the most experienced pediatric teams in the nation. We design effective treatment plans to help children with hypophosphatasia maximize their function and improve their quality of life. For babies who need more advanced care, our Neonatal Intensive Care Unit (NICU) and Colorado Fetal Care Center have experience caring for this condition and make sure you get the best care before and after birth.
• Research-based treatment: Your child receives care from a pediatric team actively involved in research to better prevent, diagnose and treat bone conditions. We conduct dozens of studies that allow us to offer the most up-to-date treatments that might not be available elsewhere.

Contact us

Schedule an appointment with the Orthopedic Institute by calling 720-777-6600.

Helpful resources

• The National Organization for Rare Disorders provides further education about hypophosphatasia, including information on clinical trials.
• Schedule an appointment with the Colorado Fetal Care Center by calling 720-777-4463.