Patau syndrome (also known as Trisomy 13) is a rare chromosomal disorder that affects fetal growth and development from the earliest stages of pregnancy. It occurs when an extra copy of chromosome 13 is present. This genetic abnormality may lead to a range of congenital abnormalities affecting different organs and body systems, including the brain, heart, face, limbs, and kidneys. As a result, it is a medical condition that requires specialized attention and care from the time it is diagnosed.The severity of symptoms and complications varies from one child to another, depending on the type of trisomy and the extent to which different organs are affected. Survival rates also vary from case to case.What causes Patau syndrome? What are its most common symptoms during pregnancy and after birth? How is it diagnosed, and are there treatments that can help improve the child's condition and manage its complications?In this article on Dalili Medical, we will explore Patau syndrome (Trisomy 13), including its causes, symptoms, diagnostic methods, and available medical and surgical treatments. We will also discuss important guidance on genetic counseling, early screening, and survival prospects.

1. What Is Patau Syndrome?

Patau syndrome, also known as Trisomy 13, is a rare chromosomal disorder that occurs when an extra copy of chromosome 13 is present in the body's cells. This can lead to a range of congenital abnormalities affecting the brain, heart, face, limbs, and other organs.

2. Is Patau Syndrome an Inherited Genetic Disorder Passed Down From Either Parent?

Most cases of Patau syndrome are not inherited from the parents. Instead, they occur due to a random error in chromosome distribution during the formation of the egg or sperm. However, some cases may be associated with a chromosomal translocation inherited from one of the parents. Therefore, chromosomal testing of both parents may be recommended to assess the risk of recurrence.

3. Can Patau Syndrome Be Detected During Pregnancy?

Yes, Patau syndrome may be suspected during pregnancy through ultrasound examinations and non-invasive prenatal testing (NIPT), which analyzes cell-free fetal DNA to estimate the likelihood of the condition. However, a definitive diagnosis requires diagnostic genetic tests, such as chorionic villus sampling (CVS) or amniocentesis.

4. Can a Baby With Patau Syndrome Survive?

Yes, some babies with Patau syndrome can survive for varying periods. However, the condition is associated with health complications and congenital abnormalities that may be severe and can affect survival. The outlook varies from one child to another depending on the type of trisomy, the severity of associated abnormalities, and the response to medical care.

5. Does Patau Syndrome Cause Intellectual Disability?

Yes, Patau syndrome is commonly associated with severe delays in cognitive, intellectual, and motor development. Affected children may experience significant difficulties with learning, communication, movement, and acquiring everyday skills. The degree of impairment varies depending on the type of chromosomal abnormality and how widely it is present throughout the body's cells.

6. Can Patau Syndrome Be Fatal?

Yes, Patau syndrome can be fatal, particularly in severe cases involving serious congenital abnormalities of the heart, brain, or respiratory system. A significant proportion of deaths occur around the time of birth or during the first few months of life. However, some affected children may survive for longer periods, depending on the severity of their condition and their response to medical care.

7. Is It Possible to Become Pregnant Again After Having a Child With Patau Syndrome?

Yes, it is possible to become pregnant again after having a child with Patau syndrome. However, the risk of recurrence depends on the type of chromosomal abnormality responsible for the condition.

Genetic counseling is therefore recommended. The doctor may also recommend chromosomal testing of the child and both parents to determine the cause of the condition, assess the risk of recurrence, and discuss appropriate screening and diagnostic tests for a future pregnancy.

8. Does Advanced Maternal Age Increase the Risk of Patau Syndrome?

Yes, the likelihood of Trisomy 13 increases with advancing maternal age, particularly after the age of 35, due to a higher chance of errors in chromosome distribution during egg formation. However, Patau syndrome can occur at any maternal age and is not limited to babies born to older mothers.

What Are the Causes of Patau Syndrome (Trisomy 13)?

Patau syndrome occurs when an extra copy of chromosome 13 is present in the cells of the developing fetus. This abnormality may be present in all cells or only in some of them. The underlying mechanism varies according to the type of chromosomal change. The main causes include:

1. Chromosomal Nondisjunction: This is the most common cause. It occurs when chromosomes fail to separate properly during the formation of the egg or sperm, resulting in an extra copy of chromosome 13 in the fetal cells.

2. Chromosomal Translocation: This occurs when extra genetic material from chromosome 13 becomes attached to another chromosome. This abnormality may be inherited from one parent if they carry a balanced chromosomal translocation without showing any symptoms.

3. Chromosomal Mosaicism: This results from an error in cell division after fertilization, leading to two different cell populations in the fetus: one with the normal number of chromosomes and another containing an extra copy of chromosome 13.

4. Partial Trisomy 13: This occurs when an extra copy of only part of chromosome 13 is present, rather than an entire additional chromosome. Symptom severity may vary depending on the size and specific portion of the extra genetic material.

Risk Factors for Patau Syndrome

Certain factors may be associated with an increased likelihood of Patau syndrome, including:

• Advanced Maternal Age: The likelihood of certain chromosomal errors increases as maternal age advances, particularly after the age of 35.

• Family History of Chromosomal Translocations: The risk of having an affected child may be higher if one parent carries a balanced chromosomal translocation involving chromosome 13.

• Previous Pregnancy Affected by Patau Syndrome: This may warrant genetic counseling and chromosomal testing of both parents to identify the cause and assess the likelihood of recurrence in future pregnancies.

What Are the Symptoms of Patau Syndrome (Trisomy 13)?

The symptoms of Patau syndrome vary from one child to another, depending on the type of chromosomal abnormality and the extent to which different organs are affected. Symptoms are generally more severe in cases of full trisomy 13, while their severity may vary in mosaic or partial trisomy cases.

The most common symptoms and abnormalities associated with the condition include:

1. Brain and Nervous System Abnormalities: These may include a small head (microcephaly), incomplete separation of the brain into two hemispheres, a condition known as holoprosencephaly, severe intellectual and motor developmental delays, low muscle tone, and seizures in some children.

2. Facial and Head Abnormalities: These may include cleft lip, cleft palate, abnormally small eyes (microphthalmia), absence of one or both eyes, closely spaced eyes (hypotelorism), a small jaw, ear abnormalities, and areas of missing skin on the scalp.

3. Heart Defects: Many children with Patau syndrome have congenital heart defects, the most common of which include:

• Atrial septal defects (ASDs).

• Ventricular septal defects (VSDs).

• Patent ductus arteriosus (PDA), in which a fetal blood vessel remains open after birth.

• Other abnormalities affecting the structure and function of the heart.

4. Hand and Foot Abnormalities: These may include polydactyly, meaning extra fingers or toes, abnormally flexed fingers, small fingernails, and foot deformities.

5. Breathing Problems: These may include difficulty breathing and abnormal breathing patterns. Some babies may experience repeated episodes of apnea, or brief pauses in breathing, which may require respiratory support after birth.

6. Digestive and Feeding Problems: These may include difficulty sucking and swallowing, poor weight gain, and abdominal wall defects that allow some internal organs to protrude outside the body, such as an omphalocele.

7. Kidney and Urinary Tract Abnormalities: These may include kidney cysts, enlarged kidneys, or structural abnormalities that may affect urinary system function.

8. Hearing and Vision Problems: These may include hearing impairment or hearing loss, small eyes, abnormalities of the retina or optic nerve, and involuntary eye movements.

9. Growth and Developmental Delays: These may appear as low birth weight, delayed acquisition of motor and cognitive skills, and slower overall growth compared with other children of the same age.

Symptoms of Patau Syndrome During Pregnancy

Certain signs that may raise suspicion of Patau syndrome in the fetus can be detected through prenatal examinations, particularly ultrasound scans. The most notable signs include:

• Poor fetal growth inside the uterus.

• Low fetal weight compared with the gestational age.

• Congenital heart defects.

• Abnormalities in brain development.

• Cleft lip or cleft palate.

• Extra fingers or toes (polydactyly).

• Kidney or abdominal wall abnormalities.

These findings may raise suspicion of Patau syndrome, but they cannot confirm the condition on their own. A definitive diagnosis requires appropriate genetic testing, such as chorionic villus sampling or amniocentesis, depending on the doctor's assessment.

How Is Patau Syndrome (Trisomy 13) Diagnosed?

The diagnosis of Patau syndrome involves several tests that help identify the possibility of the condition during pregnancy or confirm it after birth. These include imaging tests, genetic testing, and a clinical examination of the child.

First: Diagnosing Patau Syndrome During Pregnancy

Patau syndrome may be suspected through certain prenatal tests, followed by confirmation using appropriate genetic diagnostic procedures. These include:

1. Ultrasound Scan: This helps detect certain congenital abnormalities that may be associated with the syndrome, such as heart and brain defects, cleft lip, polydactyly, kidney abnormalities, and poor fetal growth inside the uterus. However, ultrasound alone is not sufficient to confirm the diagnosis.

2. Nuchal Translucency (NT) Screening: This test is performed during the first trimester, usually between weeks 11 and 14 of pregnancy, to measure the fluid-filled space at the back of the baby's neck. An increased measurement may indicate a higher likelihood of a chromosomal disorder, but it does not confirm Patau syndrome.

3. Non-Invasive Prenatal Testing (NIPT): This is a maternal blood test that analyzes fragments of DNA associated with the placenta circulating in the mother's blood. It helps estimate the likelihood of the fetus having Trisomy 13. NIPT is a highly accurate screening test, but it is not a definitive diagnostic test. Therefore, a positive result requires confirmatory diagnostic testing.

4. Chorionic Villus Sampling (CVS): This procedure is usually performed between weeks 10 and 13 of pregnancy. A small sample of placental tissue is collected and analyzed to detect an extra copy of chromosome 13. It is one of the diagnostic tests that can be used to confirm the condition.

5. Amniocentesis: This procedure is usually performed from week 15 of pregnancy onward. A small amount of amniotic fluid surrounding the fetus is collected using a thin needle under ultrasound guidance. The cells in the sample are then analyzed to detect chromosomal abnormalities, including Trisomy 13.

Second: Diagnosing Patau Syndrome After Birth

If the syndrome is not detected during pregnancy, it may be suspected after birth when the baby shows a combination of congenital abnormalities and characteristic physical features. Diagnosis is confirmed through the following tests:

1. Clinical Examination of the Baby: The doctor examines the shape of the head and face, the structure of the hands and feet, and the number of fingers and toes. They also look for signs such as cleft lip and cleft palate, while assessing the baby's growth, movement, muscle tone, and responses to stimuli.

2. Chromosome Analysis (Karyotyping): This is one of the most important tests used to confirm the diagnosis. A blood sample is taken from the baby and analyzed to determine whether an extra copy of chromosome 13 is present. Karyotyping also helps identify the type of chromosomal abnormality, whether it is full trisomy, mosaic trisomy, or the result of a chromosomal translocation.

3. Chromosomal Microarray Analysis (CMA): This test helps detect gains or losses of genetic material, including an extra copy of part of chromosome 13. It may be requested when partial trisomy is suspected or when more detailed identification of the genetic abnormality is needed.

4. Echocardiography: This ultrasound examination of the heart is used to detect congenital heart defects, such as holes between the heart chambers or a patent ductus arteriosus, and to assess how these abnormalities affect heart function.

5. Brain and Kidney Imaging: The doctor may request brain imaging using ultrasound or magnetic resonance imaging (MRI) to identify associated brain abnormalities. Kidney ultrasound may also be performed to detect structural defects or other abnormalities.

Medication Treatment for Patau Syndrome (Trisomy 13)

There is no medication that can correct the chromosomal abnormality responsible for Patau syndrome. However, certain medications can be used to manage the symptoms and health complications associated with the condition, depending on the child's medical needs and overall health. Treatment varies from one child to another according to symptom severity and the organs affected.

First: Types of Medications Used to Treat Patau Syndrome Symptoms

Medications that a doctor may prescribe to manage symptoms and complications associated with the syndrome include:

1. Anticonvulsant Medications: These are used to control epileptic seizures and convulsions that may occur due to abnormalities affecting the brain and nervous system. The doctor determines the medication and dosage based on the child's age, weight, type of seizures, and overall health.

2. Pain Relievers: These medications help relieve pain and discomfort caused by health complications or various medical procedures. The doctor selects an appropriate pain reliever based on the child's age, weight, and medical condition.

3. Medications to Support Breathing: Some children may need bronchodilators if they have airway narrowing or respiratory problems that respond to this type of treatment. Additional respiratory support, such as oxygen therapy or mechanical ventilation, may also be required depending on the severity of the condition.

4. Antibiotics: These are used to treat bacterial infections, such as pneumonia, respiratory tract infections, or urinary tract infections. They are not routinely prescribed to prevent infections unless there is a medical indication.

5. Diuretics: In some cases, doctors may prescribe diuretics to manage fluid retention or symptoms of heart failure. These medications help reduce fluid buildup and decrease the workload on the heart.

6. Medications to Manage Heart Function and Blood Pressure: A child may need medications to improve heart function or regulate blood pressure, particularly when congenital heart defects affect blood circulation. The choice of medication depends on the type of heart defect and how it affects cardiac function.

7. Medications for Gastroesophageal Reflux: These may be used to relieve reflux symptoms, such as vomiting and discomfort after feeding, when medically necessary and based on the doctor's assessment.

8. Laxatives: A doctor may prescribe laxatives to treat constipation, particularly in children with limited mobility or feeding difficulties. The type and dosage must be appropriate for the child's age and medical condition.

Second: Medical Care Accompanying Medication Treatment

In addition to medications, a child with Patau syndrome may require various medical interventions and supportive care to manage symptoms, improve comfort, and support functional abilities as much as possible. These may include:

• Nutritional Support: This involves managing feeding, monitoring the child's weight and nutritional needs, and adjusting feeding methods as necessary. Some children may require a feeding tube, such as a gastrostomy tube, to ensure adequate nutrition when they have severe difficulties with swallowing or feeding.

• Respiratory Support: This may include oxygen therapy or mechanical ventilation in cases of severe breathing difficulties or recurrent episodes of apnea, depending on the child's condition.

• Physical and Rehabilitative Therapy: This helps support mobility, improve functional abilities, and address muscle weakness and motor developmental delays, according to the child's capabilities and medical condition.

• Palliative Care: This aims to relieve pain and distressing symptoms, improve the child's comfort and quality of life, and provide psychological and medical support to the family. It can be provided alongside other treatments, depending on the child's needs and the agreed-upon goals of care.

Surgical Treatment for Patau Syndrome (Trisomy 13)

There is no definitive surgical cure for Patau syndrome (Trisomy 13), as it is a chromosomal disorder caused by an extra copy of chromosome 13. Surgery cannot correct this genetic abnormality.

However, certain surgical procedures may be used to treat congenital abnormalities and complications associated with the syndrome. Their goals are to improve organ function, relieve symptoms, and enhance the child's comfort and quality of life as much as possible.

The choice of surgery depends on the type and severity of the congenital abnormality, the child's overall health, and their ability to tolerate anesthesia and surgical intervention. Decisions are also made collaboratively by the medical team and the family, taking into account the expected benefits, potential risks, and goals of care.

First: Types of Surgical Procedures Used to Treat Complications of Patau Syndrome

1. Surgery for Congenital Heart Defects

Many children with Patau syndrome have congenital heart defects, such as atrial or ventricular septal defects and patent ductus arteriosus. A pediatric cardiologist and pediatric cardiac surgeon may recommend surgery in certain cases when the procedure is expected to provide a clear benefit to the child.

The most common procedures include:

• Ventricular Septal Defect (VSD) Repair: This is usually performed through open-heart surgery. The surgeon accesses the heart and uses a medical patch to close the opening between the ventricles. A heart-lung bypass machine may be used during the procedure when necessary.

• Atrial Septal Defect (ASD) Repair: The opening between the atria can be closed using a surgical patch or, in suitable cases, through cardiac catheterization, depending on the nature of the defect.

• Patent Ductus Arteriosus (PDA) Closure: This procedure aims to prevent continued blood flow through the ductus arteriosus after birth. Closure may be performed surgically using clips or sutures, or through catheterization in selected cases.

• Surgery for Complex Heart Defects: Some children may require more complex procedures, depending on the type of heart abnormality and its effect on blood circulation and cardiac function.

The decision to perform heart surgery is not based solely on the presence of a defect. It also depends on how significantly the defect affects the child's health and the expected benefits of repairing it.

2. Cleft Lip and Cleft Palate Repair

A child with Patau syndrome may be born with an opening in the upper lip or the roof of the mouth. These abnormalities can cause difficulties with breastfeeding and feeding and may affect breathing and oral functions later in life.

The main surgical procedures used to correct these abnormalities include:

• Cleft Lip Repair: This procedure is performed under general anesthesia. The surgeon repositions the tissues and muscles around the cleft and then sutures them together to restore the shape and function of the lip as much as possible.

• Cleft Palate Repair: This procedure involves repositioning the tissues on both sides of the cleft to cover the opening in the roof of the mouth. The tissues are then sutured together to separate the oral and nasal cavities and improve palatal function, potentially supporting feeding and speech development in the future.

The timing of these procedures is determined according to the child's medical condition, ability to tolerate anesthesia, and the expected benefits of surgery. They are not automatically performed in every child with the syndrome.

3. Omphalocele Repair

Some children with Patau syndrome may have an omphalocele, a congenital abdominal wall defect in which some internal organs, such as the intestines and sometimes the liver, protrude through an opening in the abdominal wall near the umbilicus. These organs are covered by a membrane.

The surgical approach varies depending on the size of the omphalocele and the child's condition. Options include:

• Primary Closure: This approach is used when the abdominal cavity has enough space to accommodate the protruding organs. The organs are returned to their normal position, and the abdominal wall is surgically closed without placing excessive pressure on the internal organs or compromising breathing.

• Staged Repair: This may be used for large omphaloceles when it is not possible to safely return all the organs to the abdomen in a single operation. A special protective covering known as a silo is placed around the protruding organs. They are then gradually returned to the abdominal cavity in stages, before the abdominal wall is closed when the child's condition allows.

The choice of procedure depends on the size of the omphalocele, which organs are outside the abdomen, the capacity of the abdominal cavity to accommodate them, and the child's respiratory and circulatory condition.

4. Gastrostomy Tube Placement

A child may have severe difficulty swallowing or feeding, or may be unable to obtain adequate nutrition orally. In such cases, a feeding tube that connects directly to the stomach may be needed to provide nutrition, fluids, and medications.

How the Procedure Is Performed:

1. The child receives appropriate anesthesia based on their medical condition.

2. The surgeon makes a small incision in the abdominal wall to access the stomach.

3. A feeding tube is inserted into the stomach through the opening.

4. The tube is secured to help prevent it from moving or coming out.

5. The tube is then used to administer milk, fluids, and medications according to the child's prescribed nutritional and medical plan.

The procedure may be performed using minimally invasive laparoscopic surgery or through open surgery, depending on the child's condition and the medical assessment.

5. Tracheostomy

Some children with severe respiratory problems or persistent airway obstruction may need a surgical opening in the trachea, known as a tracheostomy. This creates a direct airway passage to help air reach the lungs.

How the Procedure Is Performed:

1. The child receives appropriate anesthesia. General anesthesia is commonly used when suitable.

2. The surgeon makes an incision in the front of the neck.

3. The surgeon accesses the trachea and creates a small opening in its wall.

4. A special tube is inserted through the opening to allow air to flow in and out.

5. The tube is secured and may be connected to a mechanical ventilator if the child requires respiratory support.

Not all children with Patau syndrome need this procedure. It is reserved for selected cases in which the expected benefits are appropriate for the child's condition and goals of care.

6. Hydrocephalus Surgery

If a child with Patau syndrome develops hydrocephalus, a condition involving the accumulation of cerebrospinal fluid (CSF) in the cavities of the brain, surgery may be needed to drain the excess fluid and reduce pressure inside the skull. The appropriate procedure depends on the cause and severity of the condition.

The main surgical options include:

• Ventriculoperitoneal (VP) Shunt Placement: The surgeon inserts a thin tube into one of the brain's ventricles and connects it to another tube that runs under the skin into the abdominal cavity. The excess cerebrospinal fluid is drained into the abdomen, where it is absorbed by the body.

• Endoscopic Third Ventriculostomy (ETV): The surgeon uses a small endoscope to access the third ventricle of the brain and create a small opening that allows cerebrospinal fluid to flow through alternative pathways. This helps relieve fluid buildup in certain types of hydrocephalus.

The suitability of surgery is determined according to the cause and severity of hydrocephalus, associated brain abnormalities, and the expected benefits of the procedure.

7. Polydactyly Surgery (Removal of Extra Fingers or Toes)

A child with Patau syndrome may be born with extra fingers or toes, a condition known as polydactyly.

How the Procedure Is Performed:

1. An orthopedic or hand surgeon examines the extra digits and assesses their connections to the bones, tendons, nerves, and blood vessels.

2. The surgeon determines the structure of the extra digit and how it affects hand or foot function.

3. The procedure is performed under anesthesia appropriate for the child's condition.

4. The surgeon removes the extra digit, addressing any associated tissues, bones, or tendons when necessary.

5. The surgical site is closed with medical sutures. The child may require follow-up care or rehabilitation after surgery.

This procedure may be postponed or considered unnecessary in some cases, particularly when the extra digits do not affect hand or foot function, or when the child has more urgent medical problems that need to be addressed first.

Second: Do All Children with Patau Syndrome Need Surgery?

No. Surgical needs vary from one child to another, and not every child with Patau syndrome requires the procedures mentioned above.

Some children may only need supportive treatment and palliative care, while others may benefit from specific procedures to correct treatable abnormalities, provided their medical condition allows surgery and the expected benefits outweigh the risks.

The main factors influencing the decision to proceed with surgery include:

• The type of chromosomal abnormality, whether full, mosaic, or partial trisomy.

• The severity of associated congenital abnormalities.

• The extent to which the heart, brain, and respiratory system are affected.

• The child's ability to tolerate anesthesia and surgery.

• The expected benefits of the procedure compared with its potential risks.

• The goals of care agreed upon by the family and medical team, while prioritizing the child's best interests and comfort.

Third: Potential Complications and Risks of Surgery

Children with Patau syndrome may face additional risks during and after surgery due to multiple congenital abnormalities and the possibility that certain organs may be affected, particularly the heart, lungs, and nervous system.

Potential complications include:

• Breathing difficulties or the need for continued respiratory support after surgery.

• Impaired heart function or circulatory problems during anesthesia or after surgery.

• Infection at the surgical site or elsewhere in the body.

• Bleeding or delayed wound healing.

• Complications associated with general anesthesia.

• Failure to achieve the expected functional improvement from the procedure.

• The need for additional surgeries or subsequent medical interventions.