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Facts for people and families with Hyperparathyroidism-jaw tumour (HPT-JT) syndrome

This fact sheet contains general information about HPT-JT syndrome. Each person should be referred to a genetic service for further information and advice. 

Key Points

  • HPT-JT syndrome is due to faults (mutations) in the CDC73 gene.
  • People with HPT-JT syndrome have an increased chance of developing parathyroid disease including parathyroid cancer.
  • People with HPT-JT syndrome have an increased chance of developing benign (non-cancerous) tumours of the jaw (ossifying fibromas) and tumours and cysts of the kidney.
  • Women with HPT-JT syndrome have an increased chance of developing benign tumours of the uterus (uterine fibroids and polyps).
  • Family members (including children) can be referred to a genetic service where experts can provide information, advice and support about their chance of developing cancer and the option of genetic testing.
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HPT-JT is caused by faults in the CDC73 gene. The CDC73 gene is a ‘tumour protection’ gene that helps to protect against benign and malignant (cancerous) tumours. 

Everyone has two CDC73 genes (one from their mother, and one from their father). If one of the genes is not working, this is known as having a faulty CDC73 gene, or, having a CDC73 mutation. People with a faulty CDC73 gene are known to have Hyperparathyroidism-jaw tumour syndrome.

Cancer:

  • People with HPT-JT syndrome have about a 20-30% chance of developing parathyroid cancer over their lifetime.

Benign tumours:

  • People with HPT-JT syndrome have a 65-100% chance of developing hyperparathyroidism (high parathyroid hormone [PTH] and calcium levels in the blood) over their lifetime.
  • People with HPT-JT syndrome have about a 10-30% chance of developing a tumour in the jaw (called an ossifying fibroma) over their lifetime.
  • People with HPT-JT syndrome have about a 15% chance of developing a tumour or cysts in the kidney(s) over their lifetime.
  • Women with HPT-JT syndrome have about a 40% chance of developing benign tumours of the uterus over their lifetime.
  • Not everyone with HPT-JT syndrome will develop a tumour and/or cancer.
  • To find hyperparathyroidism and parathyroid cancer early, people with HPT-JT syndrome should have screening every year from age 10 years. This involves having a blood test to check their calcium, phosphate, vitamin D and parathyroid hormone levels and an examination of their neck by a doctor.
  • Hyperparathyroidism can be dangerous during pregnancy. A woman with HPT-JT syndrome should be checked for hyperparathyroidism before becoming pregnant. Once pregnant, a woman with HPT-JT should consider having their care through a specialist high-risk pregnancy clinic. 
  • To find tumours of the jaw early, people with HPT-JT syndrome should have their jaw checked every 5 years from age 10 years. This involves having an x-ray of the jaw.
  • To find kidney tumours and cysts early, people with HPT-JT syndrome should have their kidneys checked every 5 years from age 10 years. This involves having an ultrasound of the kidney.
  • There is no recommended screening for benign tumours of the uterus for people with HPT-JT syndrome.

Family members (including children) of someone with a faulty CDC73 gene can have genetic testing to check who has the faulty gene and who does not. Their doctor can refer them to a genetic service to find out more about their chance of developing cancer and what genetic testing involves.

If a person does have the faulty CDC73 gene:

  • they can pass it on to their children
  • each child has a 50% (1 in 2) chance of being born with it. Pregnancy planning options are available to people who want to prevent the faulty gene from being passed on.

If a person does not have the faulty CDC73 gene:

  • they have the same chance of developing tumours and/or cancer as the general population (unless there are other factors that increase this risk)
  • they cannot pass it on to their children.
People who decide not to have genetic testing should still get advice about managing their chance of developing cancer.

Version 3

Date Summary of changes
10/04/2024

Consumer information sheet reviewed alongside ID 3575 following October 2023 cancer genetics reference committee meeting. Approved for publication with the following changes made: 

  • Key points: added '... benign tumours of the uterus (uterine fibroids and polyps).'
  • What is the risk of cancer and tumours for people with HPT-JT syndrome?
    • Cancer: '...about a 25% chance of developing parathyroid cancer...'  changed to ' about a 20-30% chance of developing parathyroid cancer...'
    • Benign tumours:
      •  '...a 75–100% chance of developing hyperparathyroidism...' changed to 'a 65-100% chance of developing hyperparathyroidism'
      • '...about a 30% chance of developing a tumour in the jaw...' changed to '...about a 10-30% chance of developing a tumour in the jaw...'
      • '..about a 45% chance of developing uterine fibroids...' changed to '...about a 40% chance of developing benign tumours of the uterus...'
  • How can this increased risk of cancer and tumours be managed?
    • Bullet 1: added '...phosphate, vitamin D and parathyroid hormone levels...'
    • Added 'Hyperparathyroidism can be dangerous during pregnancy. A woman with HPT-JT syndrome should be checked for hyperparathyroidism before becoming pregnant. Once pregnant, a woman with HPT-JT should consider having their care through a specialist high-risk pregnancy clinic.'

Version increased to V.3. To be reviewed alongside ID 3575 when next due for review. 

Version 2

Date Summary of changes
29/11/2021

Consumer information sheet reviewed alongside ID 3575 following September 2021 cancer genetics reference committee meeting. Approved for publication with the following changes made: 

  • Key points: added 'Women with HPT-JT syndrome have an increased chance of developing benign tumours of the uterus (uterine fibroids).'
  • What is the risk of cancer and tumours for people with HPT-JT syndrome?
    • Cancer: '...about a 40% chance of developing parathyroid cancer...' changed to '...about a 25% chance of developing parathyroid cancer...' 
    • Benign tumours:
      • '...about a 75% chanced of developing hyperparathyroidism...' changed to '...a 75–100% chanced of developing hyperparathyroidism...'
      • '...about a 13% chance of developing a tumour or cysts in the kidney(s)...' changed to '...about a 15% chance of developing a tumour or cysts in the kidney(s)...'
      • Added 'Women with HPT-JT syndrome have about a 45% chance of developing uterine fibroids over their lifetime'
  • How can this increased risk of cancer and tumours be managed?
    • Bullet 1: added 'and an examination of their neck by a doctor'
    • Bullet 4: added 'There is no recommended screening for uterine fibroids for women with HPT-JT syndrome.'

Version increased to V.2. To be reviewed alongside ID 3575 when next due for review. 

Version 1

Date Summary of changes
30/05/2019

Developed in conjunction with associated risk management protocol ID 3575 following the November 2018 CG reference committee meeting. Discussions continued over email and document approved for publication. V.1.

To be next reviewed alongside ID 3575 when next due for review. 

This cancer genetics fact sheet is a guide only and cannot cover every possible situation. The information provided is not intended to replace discussion with a health professional, and should not be interpreted as medical advice. While eviQ endeavours to link to reliable sources that provide accurate information, eviQ and the Cancer Institute NSW do not endorse or accept responsibility for the accuracy, currency, reliability or correctness of the content of linked external information sources. Use of this document is subject to eviQ's disclaimer available at www.eviQ.org.au/copyright  

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The currency of this information is guaranteed only up until the date of printing, for any updates please check:

https://www.eviq.org.au/p/3640

17 Apr 2024