Hypophosphatasia

Overview

Hypophosphatasia (say: hy-po-FOS-fa-tay-zha) is a rare, inherited condition that affects how the body builds bones and teeth. It happens when the body makes too little of a working enzyme called alkaline phosphatase (ALP). An enzyme is a protein that helps speed up chemical reactions in the body. Without enough working ALP, certain minerals cannot settle properly into bone and teeth, so bones can be soft, weak, or slow to harden. The condition can be very mild, causing only dental problems, or more serious, affecting many bones. It is present from birth, even if signs only appear later in life.

No. Hypophosphatasia is rare. Exact numbers are not known because mild cases are often never diagnosed, but the severe forms are very uncommon.

It can affect anyone, because it is passed down through families. The severe forms usually show up in babies and young children. Milder forms are often first noticed in older children or in adults, sometimes when a person has repeated broken bones or loses adult teeth early. It affects males and females equally and is seen in all ethnic groups.

Symptoms

Common symptoms

• Bone pain, especially in the legs, hips, or feet
• Bones that break more easily than expected, or heal slowly
• Muscle weakness or a tired, aching feeling
• A waddling or unusual way of walking
• Loose teeth or early loss of teeth
• Short stature in some people
• Joint pain or stiffness
• Feeling very tired

Symptoms in children

• Baby teeth falling out too early — often before age 5 — sometimes with the root still attached
• Slow growth or being much shorter than other children the same age
• Delayed sitting, crawling, or walking
• Soft or oddly shaped skull bones in babies
• Bow legs or other leg shape changes
• Poor feeding and slow weight gain in babies
• In the most severe forms, serious breathing difficulty in a newborn

Symptoms in older adults

• Broken bones in the foot or hip that happen without a big injury, and heal slowly
• Long-standing bone or joint pain that has never been fully explained
• Losing adult teeth earlier than usual, or loose teeth
• Calcium deposits in the kidneys or joints, which can cause pain or kidney stones
• Muscle weakness that makes walking or climbing stairs harder
• Sometimes a diagnosis is only made after a low alkaline phosphatase result on a routine blood test

Causes

Main causes

• Hypophosphatasia is caused by changes (variants) in the ALPL gene. This gene holds the instructions for making an enzyme called tissue-nonspecific alkaline phosphatase, which is needed for bones and teeth to harden properly.
• When both copies of the gene are changed, the condition is usually more serious. When only one copy is changed, the condition is often milder and may only be noticed in adulthood.
• It is inherited — passed from parents to children. Sometimes a child inherits it from parents who have no symptoms themselves.

Risk factors

• Having a family member with hypophosphatasia or with unexplained early tooth loss or frequent fractures
• Parents who both carry a changed copy of the ALPL gene
• Being born to parents who are closely related, which makes it more likely both carry the same gene change
• A previous child in the family born with a severe bone condition

When to see a doctor

See a doctor urgently if:

• You or your child has a new fracture or a bone injury that is very painful
• A baby has trouble breathing, feeds poorly, or feels floppy
• A child's teeth are falling out far earlier than expected
• You have severe bone pain that is getting worse, or you cannot walk normally
• You have blood in your urine or severe pain in your side or back

Book a routine appointment if:

• You have repeated broken bones without a clear cause
• You have long-term bone or joint pain that has not been explained
• A blood test has shown a low alkaline phosphatase level
• You lost adult teeth early, or your teeth feel loose
• A family member has been diagnosed with hypophosphatasia and you want to discuss your own risk
• Your child is much shorter than expected or is late to walk

Diagnosis

Doctors usually start with a conversation about your symptoms and family history, a physical examination, and a blood test. A low level of alkaline phosphatase on a blood test is often the first clue. Because the condition is rare and can look like other bone problems, some people are referred to a specialist such as a bone doctor (orthopaedic doctor), a hormone and bone specialist (endocrinologist), a metabolic bone clinic, or a clinical geneticist. Diagnosis is confirmed by finding the typical pattern of results and, where appropriate, a genetic test.

Tests that may be done

• A blood test to measure alkaline phosphatase and other minerals such as calcium and phosphate
• A blood test to look for substances that build up when alkaline phosphatase is low, such as vitamin B6 (pyridoxal phosphate)
• A urine test to check for certain natural chemicals that are higher in this condition
• X-rays of the bones, skull, or teeth to look at how the bones have formed
• A genetic test (a blood or saliva sample) to look for changes in the ALPL gene
• Dental checks and X-rays if teeth are affected
• In some cases, a bone density scan or a small bone sample (biopsy)
• During pregnancy or after birth, ultrasound scans and specialist tests may be used if a severe form is suspected

What to expect at your appointment

Some results come back in a few days, but genetic testing can take several weeks. Waiting can feel stressful, so it helps to ask what each test is for and when you will hear back. You may be seen by more than one specialist. If the diagnosis is confirmed, your team should explain what type of hypophosphatasia you have, what it may mean for you, and what support is available. Genetic counselling can help you and your family understand how it is inherited.

Treatment

There is no single cure for hypophosphatasia, but there is a lot that can be done to protect bones and teeth and to improve comfort and quality of life. Care is usually arranged by a specialist team and tailored to how much the condition affects you. Some people with very mild forms need only occasional check-ups; others need ongoing treatment and monitoring.

Self-care at home

• Keep up with regular check-ups, blood tests, and dental visits so changes are caught early
• Follow your care team's advice on physical activity — gentle, regular movement helps keep muscles and bones strong
• Ask your doctor or pharmacist before taking any new medicine or supplement, because some common treatments can affect bone health or mineral levels
• Take care to avoid falls — good lighting at home, supportive shoes, and handrails can help
• Look after your teeth with gentle brushing, regular dental checks, and prompt care for loose teeth or gum problems
• Get enough rest and pace yourself if pain or tiredness is a problem
• Keep a simple note of your symptoms and fractures so you can share them at appointments

Medical treatments

Treatment depends on the type and severity of the condition. Options include regular monitoring, physiotherapy to build strength and movement, pain relief, dental care, and orthopaedic care for fractures or bone shape problems. For people with more serious forms, specialist teams may offer treatments given through the skin or into a vein that replace the missing enzyme, and these are only available through specialist centres. Some people are also given advice or treatment about vitamin and mineral levels, such as vitamin B6, under medical supervision. Your specialist will discuss what is appropriate for you, including the benefits and risks, and will not recommend a treatment unless it is likely to help.

When is surgery considered?

Surgery is not needed for most people. It may be considered for certain fractures, for bone shape problems that affect walking or cause pain, or for dental problems. Any decision about surgery is made together with your specialist team, taking into account how fragile your bones are and how the condition affects you.

Living with this condition

Many people with hypophosphatasia live full and active lives, especially with the milder forms. Day to day, it may mean planning around pain or tiredness, being careful about falls, keeping regular dental and medical appointments, and knowing your own limits. Some people find it helpful to tell employers, schools, or coaches about the condition so they can support you.

Lifestyle tips

• Stay active in a way that suits your body — walking, swimming, and other low-impact activity are often good choices
• Build a home that is safe from falls, with good lighting, clear floors, and rails where useful
• Eat a balanced diet and ask your team whether you need any specific vitamin or mineral advice
• Avoid smoking, and limit alcohol, as both can affect bone health
• Keep a record of appointments, test results, and treatments so you can share them with any new doctor
• Connect with other people who have the same condition — it can make a rare condition feel much less lonely

Diet and exercise

There is no special diet that cures hypophosphatasia, but a balanced diet with enough calcium and vitamin D supports bone health. Do not start high-dose supplements on your own — ask your doctor or pharmacist first, because some vitamins and minerals need to be balanced carefully in this condition. Gentle, regular exercise such as walking, swimming, or physiotherapy-led strength work helps keep muscles strong and supports bone health. A physiotherapist can help you find safe activities and avoid movements that risk injury.

Mental health and emotional wellbeing

Living with a rare, lifelong condition can be hard emotionally. Pain, tiredness, repeated appointments, worries about the future, and feeling that others do not understand can all affect mood. It is completely normal to feel this way, and help is available. Talking to your doctor about how you feel is a good first step, and counselling or psychological support can make a real difference. If you ever feel overwhelmed or have thoughts of harming yourself, please reach out for help straight away — contact your local emergency number, your doctor, or a crisis support line in your area. You do not have to cope alone.

Prevention

Hypophosphatasia cannot be prevented, because it is caused by gene changes you are born with. What you can do is understand your family's risk and get advice early. If you have the condition or a family history of it, genetic counselling can explain the chance of passing it on and the options available to you. Anyone with the condition or a family history who is planning a pregnancy should talk to their doctor before conceiving.

Vaccines

There is no vaccine for hypophosphatasia. Keep up with routine vaccinations as advised for you or your child, and mention the condition to your healthcare team so any precautions can be checked.

Screening programmes

There is no general screening programme for hypophosphatasia. Testing is offered when there are signs, such as a low alkaline phosphatase level, unexplained fractures, or early tooth loss, or when there is a known family history. During pregnancy, specialist ultrasound and genetic testing may be offered to families known to be at higher risk.

Complications

If left untreated

• Bones that break more easily and heal more slowly
• Bone shape changes that can affect walking and posture
• Early loss of baby teeth or adult teeth, which can affect eating and confidence
• Long-term bone and joint pain and muscle weakness
• Calcium deposits in the kidneys or joints, which can lead to kidney stones or joint pain
• In the most severe forms in babies, serious breathing problems that need urgent intensive care
• Problems with growth and height in some children
• Emotional strain, tiredness, and reduced quality of life if pain and symptoms are not managed

Long-term outlook

The outlook varies a lot from person to person. People with mild forms often have few problems and a normal lifespan, sometimes needing only check-ups and dental care. Children with more serious forms now have more treatment options than ever before, and specialist care continues to improve. Many people with hypophosphatasia work, study, exercise, and live full lives. Regular follow-up and a good relationship with your specialist team help make the best of your long-term health.

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