Patau syndrome (also known as Trisomy 13), is a chromosomal condition, where a person has an extra copy of chromosome 13 in their cells.¹ Each person usually has two copies of each chromosome. Trisomy (‘three bodies’) means three copies of chromosomes instead of two.² Other conditions caused by trisomy include Downs syndrome (trisomy 21) and Edward syndrome (trisomy 18). Patau syndrome usually happens by chance.

Synonyms: Trisomy 13 syndrome, t13, trisomy type 13.^3,4

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:3378 Trisomy 13 syndrome

ICD-11: LD40.1 Complete trisomy 13

Patau syndrome can cause intrauterine growth restriction during pregnancy (where babies are smaller and not growing as expected) and in many cases, are unlikely to survive to birth.^1-5

Babies born with Patau syndrome are often smaller in size, have feeding difficulties, and do not grow or gain weight as expected (failure to thrive). They often have weak muscle tone (hypotonia) and have seizures. Babies may be born with:^1-5

• brain and skull differences (such as small head size, malformations of part of the brain, abnormal opening in the skull)
• heart malformations
• extra fingers and toes
• distinctive facial features (such as slopping forehead, flat cheekbone, cleft lip, cleft palate (incomplete closure of the roof of the mouth), broad and flat nose, small and widely set eyes, low-set ears).

Patau syndrome can also affect other organs such as the eyes, pelvic, lungs, liver, kidneys, urinary tract, digestive systems, and pancreas.¹ Patau syndrome is a life-limiting condition, with most babies having a reduced life expectancy of less than 1 year.^2,5 The prognosis (expected course) of Patau syndrome will look different for everyone.

Please speak to your medical team to learn more about the symptoms, complications and prognosis of Patau syndrome.

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.

Orphanet: Disability – Trisomy 13 syndrome has information about the activity limitations that people with this condition may face. Please note that this was last updated in 2018 and may not reflect the most current information.

Patau syndrome is caused by an extra copy of chromosome 13. Individuals with Patau syndrome have three copies of chromosome 13 instead of two. Patau syndrome is not inherited (passed down) from parents. This chromosomal change usually occurs randomly before birth (de novo).

Patau syndrome usually happens when chromosome 13 fails to separate properly during meiosis (formation of egg or sperm cells). As a result, one of the egg or sperm cells contains an extra copy of chromosome 13. When they combine with a normal egg or sperm cell, the baby will have three copies of chromosome 13; in total 47 chromosomes (instead of 46).⁵ As mothers get older, errors in chromosome numbers are more likely to happen in their eggs.^1,5

Patau syndrome can also happen due to error in chromosome arrangement, known as Robertsonian translocation – where a portion or all of the extra chromosome 13 becomes attached/translocated to another chromosome.¹ This results in two normal copies of chromosome 13 and a part of chromosome 13 attached to another chromosome. More information about Robertsonian translocation can be found at Centre for Genetics Education: Chromosome changes.

In rare cases, there may be mosaicism, where only some cells of the body contain the extra chromosome 13, while other cells contain the usual two copies of chromosome 13.^1,3 Individuals with Patau syndrome caused by a Robertsonian translocation or mosaicism tend to have milder features.^1,5

If you would like to learn more about the inheritance and impact of this condition, please ask your doctor for 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

Patau syndrome may be detected during pregnancy (prenatal tests) or before pregnancy in the case of in vitro fertilisation/IVF (pre-implantation genetic diagnosis).^1,5 These tests are optional and should be discussed with your medical team and genetic counsellor. They may not be covered by Medicare. More information can be found at:

• Centre for Genetics Education: Genetic screening and tests during pregnancy
• Centre for Genetics Education: Genetic screening and tests before pregnancy

Patau syndrome can also be diagnosed at birth based on characteristics physical symptoms, and confirmed with chromosome testing.^1,3,4

As part of the diagnostic process, doctors may do a differential diagnosis, where they rule out other conditions that have similar symptoms, such as Edwards syndrome (trisomy 18), Down syndrome (trisomy 21), other chromosomal conditions, Smith-Lemli-Opitz syndrome, CHARGE Syndrome, Meckel syndrome.^1,4

Information about screening and diagnostic tests for Patau syndrome can be found at: Screening and diagnosis of fetal structural anomalies and chromosome conditions (C-Obs 35) developed by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG), published in 2024.

Please speak to your medical team to learn more about the available diagnostic pathways for Patau syndrome.

There is currently no curative treatment for Patau syndrome. Treatment is targeted at managing symptoms (symptomatic management) and involves a multidisciplinary care team. This may include mechanical ventilation to help with breathing, heart surgery, orthopaedic surgery, medications to manage seizures, specialised diets, and use of hearing aids.¹

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.

Healthcare professionals involved in the care of people with Patau syndrome may include general practitioners (GP), midwifes, obstetricians, paediatricians, neonatologists, neonatal intensive care nurses, clinical geneticists, respiratory physicians, otolaryngologists, cardiologists, neurologists, urologists, orthopaedic surgeons, physiotherapists, occupational therapists, speech pathologists, and others.¹ 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.

For many rare diseases, 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

Screening and diagnosis of fetal structural anomalies and chromosome conditions (C-Obs 35) developed by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG), published in 2024.

The following guidance is available from international experts outside Australia; however, there may be information that is not relevant or applicable to the Australian context, and may not be up to date:

• Guidance for Caring for Infants and Children With Trisomy 13 and Trisomy 18: Clinical Report developed by the American Academy of Paediatrics, published in 2025.
• Surveillance guidelines for children with trisomy 13 developed by health professionals from United States of America, published in 2021.

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.

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:
Support Organisation for Trisomy (SOFT) Australia
Website: https://www.softaustralia.com.au/

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.

Patau syndrome 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.

Through The Unexpected: For Parents has information to support parents who have received a prenatal diagnosis.

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 Patau syndrome can be found at:

• Raising Children: Patau syndrome or trisomy 13
• NSW Centre for Genetics Education: Trisomy 13 – Patau Syndrome
• Better Health Channel: Trisomy disorders including Trisomy 13
• Genetic and Rare Diseases (GARD) Information Center: Complete trisomy 13 syndrome
• National Organization for Rare Disorders (NORD): Trisomy 13 Syndrome

StatPearls: Patau Syndrome

Orphanet: Trisomy 13 syndrome

Human Phenotype Ontology (HPO): Trisomy 13 syndrome

This page has been developed by Rare Voices Australia (RVA)’s RARE Portal team.

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