Primary congenital hypothyroidism (CH) is a condition in which the thyroid gland does not produce enough thyroid hormone (a type of thyroid hormone deficiency). It is a condition that is present from birth (congenital condition). It is caused by the thyroid gland not developing normally (thyroid dysgenesis) or disruption in the thyroid hormone production process.^1-3

Thyroid hormones are important for optimal growth and brain development, particularly during early life.⁵ In primary CH, the insufficient production of thyroid hormones can prevent proper growth and development. Symptoms may not always be obvious at birth, but may include prolonged jaundice (yellowing of skin and eyes), poor feeding, lethargy (extreme tiredness or lack of energy), and constipation in newborns.^2,3 If untreated, primary CH can lead to poor growth, developmental delay, delayed bone maturation and, in severe cases, permanent intellectual disability.^2,4

In Australia, primary CH is often detected shortly after birth via newborn bloodspot screening (NBS) programs. Additional testing is required to confirm the diagnosis. For individuals who are not screened at birth, primary CH often diagnosed after symptoms develop. Early diagnosis and timely, appropriate treatment of primary CH can help support optimal developmental outcomes and prevent long term complications.^2.5

Please note that this page addresses primary CH only. Primary CH can also occur as part of a broader genetic syndrome that can affect other organs in the body, such as Pendred syndrome, Bamforth-Lazarus syndrome, and others.^3,6 Congenital hypothyroidism can also occur in other forms, such as secondary CH (due to pituitary dysfunction), tertiary CH (due to hypothalamic dysfunction) or peripheral hypothyroidism due to impaired thyroid hormone action.²

Universal rare disease classifications provide a common language for recording, reporting and monitoring diseases. Please visit the Rare Disease Classifications page for more information about these internationally recognised classifications.

ORPHA:226295 Primary congenital hypothyroidism

There is no known ICD11 classification.

Symptoms of primary CH may differ between individuals. The symptoms may not always be obvious at birth but will develop over time if it is not diagnosed early and treated.³ Newborns may have prolonged jaundice (yellowing of skin and eyes), low muscle tone (hypotonia), feeding difficulties, failure to thrive, lethargy (extreme tiredness or lack of energy), hoarse cry, constipation, abnormally large tongue (macroglossia) among other symptoms.^2,3 If left untreated, primary CH can lead to poor growth, developmental delay, delayed bone maturation and, in severe cases, permanent intellectual disability.^2,4

Early diagnosis and timely, appropriate treatment can prevent some of these symptoms from developing and allow children to achieve normal growth and development.^2.5

Please speak to your medical team to learn more about the symptoms and complications of this condition.

Rare diseases are often serious and progressive, exhibiting a high degree of symptom complexity, leading to significant disability. Majority of the estimated two million Australians living with a rare disease meet the Australian Government’s definition for disability (in accordance to the Australian Public Service Commission and Australian Bureau of Statistics), and many experience severe and permanent disability impacts. If you or someone you care for is experiencing disability-related impacts from a rare condition, please speak with a health or disability professional for advice. Information about relevant disability support can be found at the RARE Portal’s Disability Support Information page.

Primary CH is caused by the thyroid gland not being able to produce enough thyroid hormone (TH).²

This is most commonly due to abnormal development of the thyroid gland (thyroid dysgenesis), which includes ectopy (abnormal location of the thyroid gland), athyreosis (complete absence of thyroid tissue), and hypoplasia (reduced size of the gland). ³

In other cases, the thyroid gland develops normally but cannot produce enough thyroid hormone due to:^1,3

• dyshormonogenesis – a genetic defect in the thyroid’s hormone production process, where enzymes needed to make thyroid hormone do not function properly
• genetic defects in the thyroid-stimulating hormone (TSH) receptor, resulting in the thyroid being unable to properly receive and respond to signals to produce hormone
• unknown (idiopathic) causes

In cases where primary CH is thought to have a genetic cause, and you would like to learn more about the inheritance and impact of this condition, you can ask your doctor about a referral to a genetic counsellor. Genetic counsellors are qualified allied health professionals who can provide information and support regarding genetic conditions and testing. More information about genetic counselling can be found at:

• Information on Genetic Services
• The National and State Services pages underneath the ‘Genetic Counselling’ sections listed

Newborn screening

In Australia, primary CH is usually detected via the newborn bloodspot screening (NBS) programs.  Shortly after birth when the baby is between 48 -72 hours of age (2-3 days old) and with parental consent, a nurse or midwife will collect the baby’s blood via a heel prick blood test. The healthcare provider will then send it to a specific laboratory to test for a range of rare conditions, including primary CH. If the results of these tests suggest that the baby is at risk of having one of these conditions, laboratory staff will quickly get in touch with healthcare providers. The healthcare providers will then arrange for the baby to have further testing that will confirm whether the baby does indeed have the condition. The healthcare providers will also organise for the baby to receive urgent care if required. Depending on your state or territory, parents may or may not receive a notification if the test results are clear. You can find out more about NBS in your state or territory at Australian Government Department of Health, Disability and Ageing: Delivering newborn bloodspot screening programs.

Newborn bloodspot screening is a reliable way to check for certain rare conditions early in life. Although it’s extremely rare, cases can sometimes be missed. If you are concerned your baby may have a condition that they have already been screened for, you should contact a medical professional.

Diagnosis

A diagnosis of primary CH may be suspected based on an abnormal result from NBS but additional tests and a clinical examination will be required to confirm a diagnosis. For individuals who are not screened at birth, primary congenital hypothyroidism is often diagnosed after symptoms develop.

Diagnosis of primary CH is typically made based on clinical examination and thyroid function tests to detect high levels of thyrotropin (also known as thyroid‑stimulating hormone or TSH) in the blood, supported by low levels of thyroxine (T4).⁵ For further information about the thyroid function tests, please visit healthdirect: thyroid function blood tests – thyroid problems, TSH, T3, T4.

As part of the diagnostic process, doctors may perform a differential diagnosis, which is to rule out other conditions that have similar symptoms, such as central (secondary or tertiary) congenital hypothyroidism.⁵

Please speak to your medical team to learn more about the available pathways for diagnosis of this condition.

There is currently no curative treatment for primary CH. Management of primary CH involves hormone replacement therapy to restore normal thyroid hormone levels, along with regular blood tests to monitor TSH and T4 levels, and regular monitoring of growth.⁵ The approach is usually tailored to the individual. With early diagnosis and timely treatment, many children with primary CH can achieve normal growth and development and may have few or no symptoms.^2,5

Please speak to your medical team to learn more about the possible treatment or management options for your condition. Treatment will depend on an individual’s specific condition and symptoms. It is also important to stay connected to your medical team so that you can be made aware of any upcoming clinical trial opportunities. For many rare diseases, treatment options may be limited. Participation in a clinical trial may provide access to new or emerging therapies.

Healthcare professionals involved in the care of individuals with primary CH may include general practitioners (GP), paediatricians, endocrinologists, geneticists and others. The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.

Clinical care for rare diseases often involves a multidisciplinary team of medical, care and support professionals. Please note that the information provided here is as a guide and that RVA does not necessarily monitor or endorse specific clinics or health experts.

This may not be applicable to all rare diseases but for many, palliative care services may be relevant and useful. Palliative care services are available for people (adults, children and their families) living with a life-limiting illness and is not only for end-of-life care. It can also help at any stage of illness from diagnosis onwards, and will look different for different people. Palliative care services provide assistance, support, resources and tools to help people manage their illness and the symptoms, ease pain, and improve comfort and quality of life. If this is relevant to you and you wish to find out more information about palliative care and how it can help you, please visit:

• Australian Institute of Health and Welfare: Palliative care Overview
• Australian Government Department of Health, Disability and Ageing: Palliative care
• Palliative Care Australia

Congenital Hypothyroidism: A 2020–2021 Consensus Guidelines Update—An ENDO-European Reference Network Initiative Endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology is an update of the 2014 international consensus practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).⁵

Individuals living with rare diseases may have complex medical issues and disabilities, which are not always visible. It is often useful to refer to their medical history as well as personal information such as a medical card, doctor’s letter, or if available, a rare disease passport, for relevant information.

In addition, individuals, their parents, families and carers often develop extensive expertise on their specific rare disease. It is important to recognise that they can contribute valuable knowledge about their rare condition. Rare diseases often impact individuals differently, so it’s important to consider a person’s lived experience.

There are specific considerations around participating in rare disease research, including clinical trials. It is important to be mindful of issues such as data privacy, research ethics, consent and differences in research regulations between Australia and other countries. For more information, please visit the RARE Portal’s Considerations for Participating in Health and Medical Research page.

If you are interested in finding clinical trials for your condition, please visit the following websites; however, there may not be any clinical trials available:

• Australian Clinical Trials
• ClinicalTrials.gov

It is best to discuss your interest in research, including clinical trials,  with your medical team to determine suitability and eligibility.

Australian Organisation:

Australian Thyroid Foundation
Website: https://www.thyroidfoundation.org.au/

The Australian Thyroid Foundation provides Australians with patient education, individual support & advocacy with thyroid cancer, all thyroid related conditions, prevention of iodine deficiency & good thyroid health.

Please note that RVA does not monitor or endorse each group/organisation’s operational governance and activities. When engaging with a group, please consider the information on the RARE Portal’s Finding Helpful Peer and Community Supports page.

Primary CH varies between individuals, and each person’s experience is unique.

If you would like to share your personal story with RVA, please visit the Rare Voices Australia: Share Your Story page. RVA will consider your story for publishing on our website and inclusion on the RARE Portal.

For information on available government and social services that provide support for individuals with a rare disease, please visit the National and State Services pages.

People living with a rare disease often face unique challenges such as diagnostic delays, misdiagnoses, limited treatment options, and limited access to rare disease specialists and support. These challenges may impact people’s emotional wellbeing and quality of life. Many find it helpful to seek mental health and wellbeing support to cope with ongoing stress and uncertainty. Connecting with people who have shared experiences through a support group may also be helpful. Information about relevant mental health and wellbeing support can be found at:

• Mental Health and Wellbeing Support for Australians Living with a Rare Disease
• The National and State Services pages underneath the ‘Mental Health’ sections listed

Further information on primary CH can be found at:

• The Australian Thyroid Foundation: Congenital Hypothyroidism
• Genetic and Rare Diseases (GARD) Information Center: Congenital hypothyroidism

Orphanet: Primary congenital hypothyroidism

This page has been co-developed by Rare Voices Australia (RVA)’s RARE Portal team in consultation with Australian Thyroid Foundation.

If you are aware of any additional information that may benefit stakeholders with an interest in this page, or if you notice any broken links or inaccurate information, please let us know via the Contribute page.