WHAT IS HYPOPHOSPHATASIA (HPP)?

Hypophosphatasia (hypo-fahs-fuh-TAY-shuh), or HPP, is a rare disorder with lifelong impact. It can affect a person’s bones, muscles, joints, teeth, lungs, brain, and kidneys. HPP is an inherited condition, so other members of a person’s family may have it, too.

Man sitting on couch looking at phone
Jump Btn

A MISSING ENZYME

People with HPP have a mutation in the ALPL gene, which means they are missing or don’t have enough of the alkaline phosphatase (ALP) enzyme. This means that people with HPP have ALP levels lower than the healthy normal for their age and gender. When this is the case, the body has trouble making healthy bones. Low ALP levels can make bones soft, weak, and deformed.

Learn more about ALP and how STRENSIQ® (asfotase alfa) works to replace it.

How STRENSIQ works

All people have the ALPL gene, which makes an enzyme called ALP. The body needs ALP to form healthy bones.

SIGNS AND SYMPTOMS

HPP looks different for every person. The condition can affect people of all ages and may vary in terms of severity of signs and symptoms—even in the same family. New symptoms can appear at any age, symptoms can continue long-term, and they can worsen over time.

HPP can affect many different parts of the body. Early tooth loss, frequent bone injuries, and muscle weakness and pain are some examples of impact.

Use the skeletal graphic to explore more impacts of HPP.

SKULL AND BRAIN
TEETH
RIBS AND LUNGS
KIDNEYS
MUSCLES AND JOINTS
BONES
Human body
×

Skull and brain

  • Abnormally shaped head
  • Seizures

Teeth

  • Early tooth loss

Ribs and lungs

  • Rib cage bones may not grow properly
  • Underdeveloped lungs
  • Breathing complications that may be severe

Kidneys

  • Buildup of calcium

Muscles and joints

  • Muscle weakness and pain

Bones

  • Weak or brittle bones
  • Frequent bone injuries
  • Bowing of the legs


SYMPTOMS THROUGHOUT A PERSON’S LIFE

Rubber duck icon
Infants
  • Short limbs, abnormal chest or head shape, and soft skull bones
  • Life-threatening complications, such as pressure on the brain, seizures, and difficulty breathing
  • When left untreated, chances of survival are low for infants with HPP
Headphones icon
Children and adolescents
  • Slow or stunted growth
  • Difficulty doing things their friends can do, from basic activities like walking, bending, or climbing stairs, to high-energy activities like riding a bike or skating
  • Muscle pain, weakness, and fatigue others their age don’t experience
Coffee mug icon
Adults
  • Difficulties that may have been experienced during childhood and adolescence
  • Daily challenges, such as trouble walking, running, standing from a sitting position, and picking things up
  • Severe bone pain that could limit activity
Person using walking cane icon

It is common for people of all ages with HPP to need some form of an assistive device to help them get around.

HOW HPP IS DIAGNOSED

A person who shows signs and symptoms of HPP should request a blood test to examine their ALP level. If blood-test results reveal their ALP level is low for someone of their age and gender, they may have HPP.

HPP is often misdiagnosed. ALP can be low because of HPP, but it can also be low for other reasons. Because HPP is rare, not every doctor has the same amount of experience with the disease. Also, some of the symptoms of HPP can be symptoms for other, more common conditions.

Woman standing with girl sitting in chair

CONDITIONS THAT CAN LOOK LIKE HPP

Below are other diseases that may be more common and have shared symptoms with HPP.

Diseases in bold often have overlapping symptoms and therefore can be common misdiagnoses.

Weak/brittle bones
  • Rickets (nutritional rickets and X-linked hypophosphatemic rickets)
  • Osteopenia/osteoporosis
  • Osteogenesis imperfecta
  • Osteomalacia
Chronic pain and joint problems
  • Osteoarthritis/arthritis
  • Rheumatoid arthritis
  • Leukemia or bone cancer
  • Fibromyalgia
  • Pseudogout
Tooth loss
  • Gum disease
  • Dentinogenesis imperfecta
Man and woman holding hands while sightseeing outdoors
Man and woman holding hands while sightseeing outdoors

WHAT WAS YOUR DIAGNOSIS JOURNEY LIKE?

Hear others talk about getting diagnosed with HPP.

SPECIALISTS WHO CAN HELP

When it comes to rare diseases, specialists are very important. They can help a person understand and manage symptoms in ways a primary physician may not be able to.

If you believe you or someone you care for has HPP, but has not been diagnosed, look for a specialist who may be familiar with HPP. Some specialists who may be able to help include:

Gene icon
Geneticists
Study the role that genes play in disease and health
Hormone icon
Endocrinologists
Study hormone imbalances
Muscle and bone icon
Orthopedists
Study the bones, joints, ligaments, tendons, and muscles
Joint and bone icon
Rheumatologists
Study pain and disorders of the joints, muscles, tendons, bones, and other connective tissues

Enroll in OneSource™ to get personalized patient support from Alexion:

LOOKING FOR RESOURCES?

Understanding HPP is easier when a community of support is eager to help. Explore the resources available for people living with HPP and their loved ones, including educational events and connecting with patient advocacy organizations.

RESOURCES
× +
IMPORTANT SAFETY INFORMATION & INDICATION

STRENSIQ may cause serious side effects, including

  • Serious allergic (hypersensitivity) reactions happened in some people who use STRENSIQ. Stop using STRENSIQ and go to the nearest hospital emergency room right away if you or your loved one have any of the signs and symptoms of a serious allergic reaction, including
    • Difficulty breathing
    • Swelling of your eyes, lips, or tongue
    • Hives
    • Feeling faint
    • Nausea or vomiting
    • Dizziness
    • Itching of your lips, tongue, or throat
    • Choking sensation
  • Skin thickening or pits at the injection site (lipodystrophy) has happened several months after using STRENSIQ.
  • Calcium buildup in the eyes and kidneys can occur if you or your loved one have HPP. Your healthcare provider should check the eyes and kidneys while you or your loved one use STRENSIQ.
  • Decreased efficacy. Contact your healthcare provider if you or your loved one notice STRENSIQ is no longer working or experience worsening symptoms of HPP (e.g., increased respiratory support, increased difficulty walking, new fractures).

The most common side effects of STRENSIQ include local skin injection-site reactions (red skin patches, bruising, color change, pain, itching, thinning, swelling, pits, and bumps) and calcium buildup in your eyes and kidneys.

Strensiq may affect other lab test results, therefore it is important that you present your Medical Alert Card to your healthcare team so they are aware that you are being treated with an alkaline phosphatase (ALP) replacement therapy which may cause incorrect results on certain laboratory tests.

Tell your doctor if you are pregnant or plan to become pregnant or are breastfeeding or plan to breastfeed.

These are not all the possible side effects of STRENSIQ. For more information, ask your healthcare provider or pharmacist. Call your healthcare provider for medical advice about side effects. You may report side effects to the US Food and Drug Administration at 1‑800‑FDA‑1088.

INDICATION
What is STRENSIQ?
Strensiq is a prescription medicine used to treat people with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP).

Please see STRENSIQ full Prescribing Information, including Patient Information and Instructions for Use.
IMPORTANT SAFETY INFORMATION & INDICATION

STRENSIQ may cause serious side effects, including

  • Serious allergic (hypersensitivity) reactions happened in some people who use STRENSIQ. Stop using STRENSIQ and go to the nearest hospital emergency room right away if you or your loved one have any of the signs and symptoms of a serious allergic reaction, including
    • Difficulty breathing
    • Swelling of your eyes, lips, or tongue
    • Hives
    • Feeling faint
    • Nausea or vomiting
    • Dizziness
    • Itching of your lips, tongue, or throat
    • Choking sensation
  • Skin thickening or pits at the injection site (lipodystrophy) has happened several months after using STRENSIQ.
  • Calcium buildup in the eyes and kidneys can occur if you or your loved one have HPP. Your healthcare provider should check the eyes and kidneys while you or your loved one use STRENSIQ.
  • Decreased efficacy. Contact your healthcare provider if you or your loved one notice STRENSIQ is no longer working or experience worsening symptoms of HPP (e.g., increased respiratory support, increased difficulty walking, new fractures).

The most common side effects of STRENSIQ include local skin injection-site reactions (red skin patches, bruising, color change, pain, itching, thinning, swelling, pits, and bumps) and calcium buildup in your eyes and kidneys.

Strensiq may affect other lab test results, therefore it is important that you present your Medical Alert Card to your healthcare team so they are aware that you are being treated with an alkaline phosphatase (ALP) replacement therapy which may cause incorrect results on certain laboratory tests.

Tell your doctor if you are pregnant or plan to become pregnant or are breastfeeding or plan to breastfeed.

These are not all the possible side effects of STRENSIQ. For more information, ask your healthcare provider or pharmacist. Call your healthcare provider for medical advice about side effects. You may report side effects to the US Food and Drug Administration at 1‑800‑FDA‑1088.

INDICATION
What is STRENSIQ?
Strensiq is a prescription medicine used to treat people with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP).

Please see STRENSIQ full Prescribing Information, including Patient Information and Instructions for Use.