The signs of Patau syndrome become evident at birth. Although microphthalmia, cleft palate and polydactyly constitute the classic triad of trisomy 13 [8], not all three signs are present in all cases of Patau syndrome. The neonate presents with variable physical defects, and upon further assessment, cardiac, neurological, renal and ocular anomalies. Some of these anomalies are listed here [5] [8] [9] [10]:

Craniofacial defects

• Scalp defects
• Low-set ears
• Cleft lip
• Cleft palate
• Bulbous nose
• Hypotelorism
• Micrognathia

Limb defects

• Polydactyly
• Rocker-bottom feet
• Single palmar crease

Heart defects

• Patent ductus arteriosus
• Atrial septal defect
• Ventricular septal defect

CNS abnormalities

• Microcephaly
• Neural tube defects
• Holoprosencephaly
• Hypoplasia of the cerebellum
• Hydrocephalus
• Spinal dysraphism

Ocular abnormalities

• Microphthalmia
• Coloboma of the iris
• Ciliary body
• Retinal dysplasia

Renal anomalies

Genitalia anomalies

These clinical findings at birth are indicative of Patau syndrome. However, diagnosis must only be made when trisomy 13 is evident on karyotyping. Parents who opt for screening of fetal chromosomal defects can find if the fetus has an extra chromosome 13 before birth. They, then, have the option of continuing or terminating the pregnancy.

The clinical signs of Patau syndrome are similar to those of Edwards syndrome [8]. Care must be taken, as this similarity often leads to misdiagnosis.

• Atrial Septal Defect

  (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases). [ncbi.nlm.nih.gov]

  There are often signs of congenital heart disease, such as: Abnormal placement of the heart toward the right side of the chest instead of the left Atrial septal defect Patent ductus arteriosus Ventricular septal defect Gastrointestinal x-rays or ultrasound [nlm.nih.gov]

  […] view 350 KB version view 9 KB version A newborn male with full trisomy 13 (Patau syndrome). this baby has a cleft palate, atrial septal defect, inguinal hernia, and postaxial polydactyly of the left hand. view 255 KB version view 25 KB version An individual [medgen.genetics.utah.edu]

• Multiple Congenital Anomalies

  Trisomy 13 or Patau syndrome (PS) is a chromosomal disorder characterized by a well known presentation of multiple congenital anomalies. Our objective was to determine the clinical features and prognosis observed in a sample of patients with PS. [ncbi.nlm.nih.gov]

  Entry H01562 Disease Name Patau syndrome; Trisomy 13 Description Patau syndrome, also known as trisomy 13, is a chromosomal disorder characterized by the severe clinical picture of multiple congenital anomalies. [genome.jp]

  Wagner: Multiple congenital anomaly caused by an extra autosome. The Lancet, London, 1960, I: 790. What is an eponym? An eponym is a word derived from the name of a person, whether real or fictional. [whonamedit.com]

  Trisomy 13 is a severe syndrome with multiple congenital anomalies and a poor prognosis. Of the rare fetuses that survive to term, most die in the first week of life and 5% survive to 6 months of age. [clinicaladvisor.com]

  Congenital anomalies include abnormalities of face, brain, extremities and heart. [ijri.org]

• Single Transverse Palmar Crease

  A single transverse palmar crease, polydactyly, and hyperconvex narrow fingernails are also common. About 80% of cases have severe congenital cardiovascular anomalies; dextrocardia is common. [merckmanuals.com]

  transverse palmar creases 0007598 Cleft palate Cleft roof of mouth 0000175 Cognitive impairment Abnormality of cognition Cognitive abnormality Cognitive defects Cognitive deficits Intellectual impairment Mental impairment [ more ] 0100543 Cystic hygroma [rarediseases.info.nih.gov]

• Epilepsy

  RESULTS: Two patients had been previously diagnosed with epilepsy (one with tonic spasms and one with multiple seizure types). We found 3 patients with photosensitive myoclonic epilepsy (37.5%), and one with non-photosensitive myoclonic epilepsy. [ncbi.nlm.nih.gov]

  With epilepsy, severe psychomotor delay and blindness can also be associated. Irving C, Richmond S, Wren C, Longster C, Embleton ND (2011) Changes in fetal prevalence and outcome for trisomies 13 and 18: a population-based study over 23 years. [oatext.com]

• Asymptomatic

  Atrial septal defect – as most cases are reported, this cardiac problem would be asymptomatic to some of the affected. What happens to the heart is that there has been an enabling of blood flow between the left and right atria. [syndrome.org]

• Failure to Thrive

  Infants who survive to one year have severe complications including intellectual disability, seizures and failure to thrive. [secure.ssa.gov]

  […] to thrive.[1] Enhancing Healthcare Team Outcomes Patau syndrome requires an interprofessional team approach. [ncbi.nlm.nih.gov]

  […] to Thrive: Family Wishes to Have Complete Repair. 61 Harahsheh AS...Cohen MS 31653287 2019 32 The role of ultrasound in women with a positive NIPT result for trisomy 18 and 13. 61 Zhen L...Li DZ 31759530 2019 33 Chip-Based Digital PCR Approach Provides [malacards.org]

  Prognosis Trisomy 18 is associated with severe mental retardation and severe failure to thrive. 50% of patients die by one week of life, and 90% of patients die by one year of life. [pedclerk.bsd.uchicago.edu]

  […] to thrive); have severe feeding difficulties; and episodes in which there is temporary cessation of spontaneous breathing (apnea). [1] Other features or trisomy 13 may include: [3] Clenched hands (with outer fingers on top of the inner fingers) Close-set [rarediseases.info.nih.gov]

• Heart Disease

  Most infants with trisomy 13 have congenital heart disease. [nlm.nih.gov]

  […] for Patau's syndrome selective pregnancy termination has been employed following amnio/CVS Complications congenital heart disease, blindness, severe mental retardation may complicate survival Please rate topic. [medbullets.com]

  disease (13%), and pneumonia (4%). [emedicine.medscape.com]

• Low Set Ears

  It leads to a variety of abnormalities that include mental retardation, microcephaly, low-set ears, eye structural defects, polydactyly, and limb abnormalities The presence of an additional (third) chromosome on an otherwise diploid chromosome 13 with [icd9data.com]

  Cutis aplasia (missing portion of the skin/hair) Prominent heel Microcephaly Low-set ears Cleft palate or hare lip Collection Procedure • Amniotic fluid Discard the first 2 cc of fluid to reduce the risk of maternal cell contamination. [cytogenx.com]

  Other birth defects of trisomy 13 include: Clenched hands Cleft lip or palate Extra fingers or toes (polydactyly) Hernias Kidney, wrist, or scalp problems Low-set ears Small head ( microcephaly ) Undescended testes Babies born with trisomy 13 can have [webmd.com]

  The infant may also have low-set ears, an abnormally small head (microcephaly), and/or missing skin on the scalp or scalp defects. Male infants may be born with an undescended testicle. Some babies are born with an umbilical and/or inguinal hernia. [actforlibraries.org]

  ears Low set ears Lowset ears [ more ] 0000369 Malar flattening Zygomatic flattening 0000272 Median cleft lip Central cleft upper lip 0000161 Microphthalmia Abnormally small eyeball 0000568 Muscular hypotonia Low or weak muscle tone 0001252 Neurological [rarediseases.info.nih.gov]

• Hearing Impairment

  Abnormality of cognition Cognitive abnormality Cognitive defects Cognitive deficits Intellectual impairment Mental impairment [ more ] 0100543 Cystic hygroma 0000476 Hydrops fetalis 0001789 Hypotelorism Abnormally close eyes Closely spaced eyes [ more [rarediseases.info.nih.gov]

• Hypertelorism

  The initial clinical examination detected polydactyly in the left hand, congenital clubfoot and convex soles, ocular hypertelorism, a low nasal bridge, numerous hemangiomas distributed throughout the body, cardiomegaly, and perimembranous inter-ventricular [ncbi.nlm.nih.gov]

  […] low-set ears, eye structural defects, polydactyly, and limb abnormalities The presence of an additional (third) chromosome on an otherwise diploid chromosome 13 with variable abnormalities, most characteristic of which are microcephaly, microphthalmia, hypertelorism [icd9data.com]

  Facial anomalies are variable and may range in severity from hypertelorism and premaxillary agenesis (80% of cases) to cebocephaly or cyclopia with absence of the nasal skeleton. [orpha.net]

  The face may also be characterized by prominent glabellae, ocular hypertelorism, anophthalmia, and micrognathia (Borges-Osório and Robinson, 2001). Our patient had prominent glabellae, ocular hypertelorism and low-set ears. [funpecrp.com.br]

  […] artery 5 retinal dysplasia 3 spinal anomalies spina bifida intrauterine growth restriction (IUGR): tends to be early abnormal facies: 90%, strong marker cleft lip +/- palate: ~45% 9 microphthalmia: rarely anophthalmia 10 micrognathia 6 hypotelorism hypertelorism [radiopaedia.org]

• Short Neck

  Other characteristics may include a short neck; loose skin folds over the back of the neck; and/or the presence of a benign lesion or birthmark consisting of abnormal clusters of blood vessels (capillary hemangiomas), most frequently on the center of [rarediseases.org]

• Nystagmus

  Heart defects Structural eye defects, including microphthalmia, Peters anomaly, cataract, iris and/or fundus (coloboma), retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia Meningomyelocele (a spinal [cytogenx.com]

  Structural eye defects, including microphthalmia, Peters' anomaly, cataract, iris or fundus (coloboma), retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia Meningomyelocele (a spinal defect) Musculoskeletal [en.wikipedia.org]

  Structural eye defects, including microphthalmia, Peters anomaly (a type of eye abnormality), cataract, iris and/or fundus (coloboma), retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia Meningomyelocele [intelligentdental.com]

  Diagnosis Symptoms Seizures Vision problems Physical Examination Skin Cutis aplasia (missing portion of the skin/hair) Head Microcephaly Eyes Microphthalmia Cataract Iris and/or fundus (coloboma) Retinal detachment Nystagmus Optic nerve hypoplasia Hypertelorism [wikidoc.org]

• Cryptorchidism

  Genitals are frequently abnormal in both sexes; cryptorchidism and an abnormal scrotum occur in boys, and a bicornuate uterus occurs in girls. [merckmanuals.com]

  The major clinical findings include cryptorchidism, abnormal auricles, congenital heart defects, polydactyly, microphthalmia, and micrognathia. [genome.jp]

  […] hypotelorism hypertelorism cyclopia proboscis skeletal abnormalities polydactyly: 70% (tends to be post-axial) rocker bottom feet clenched hands +/- overlapping digits abdominal wall abnormalities bladder exstrophy omphalocele genitourinary anomalies cryptorchidism [radiopaedia.org]

The clinical diagnosis of Patau syndrome is made either prenatally or at birth. In both cases, evidence of trisomy 13 on cytogenetic analysis is a sure diagnosis of Patau syndrome.

Prenatally, cytogenetic analysis can be done using chorionic villous sampling (10-13 weeks' gestation) or amniocentesis (15 weeks' gestation or later). Non-invasive methods like cfDNA from maternal blood are highly sensitive and specific, and therefore, promising [11].

After birth, conventional cytogenetic or FISH (Fluorescence in Situ Hybridization) studies can show trisomy 13. FISH can describe some chromosomal anomalies more accurately.

A cytogenetic analysis may reveal free trisomy 13, partial trisomy 13 or Robertsonian translocation [7]. Free trisomy 13 rarely recurs. However, the latter two variants have a high risk of recurrence, and therefore, should be followed with cytogenetic analysis of parents. Genetic counseling should be recommended to parents with high risk of recurrence.

A neonate with Patau syndrome requires detailed workup to evaluate the severity of the condition. All systems, especially CNS and heart, should be assessed through metabolic workup and imaging studies.

Patau syndrome, like other trisomies, has no treatment. Therapy aims to support defective organs of the body, prevent complications and prolong survival of the neonate.

Parents of such children should be recommended psychological therapy and genetic counseling. They should also be connected to support groups, comprising of other parents whose children also suffered from Patau syndrome [8].

Patau syndrome, like other trisomies, has no treatment. Therapy aims to support defective organs of the body, prevent complications and prolong survival of the neonate. Despite that, the prognosis remains poor.

Median survival age for children with Patau syndrome is less than 3 days. Those who do survive for longer time exhibit severe mental retardation and developmental delays [8] [9].

Patau syndrome is a genetic disorder, caused by presence of three copies of chromosome 13, instead of normal two.

Patau syndrome is rare, with the incidence of about 1-2 cases from 10,000 births. It is the third most frequent trisomy among live births [1]. Like other trisomies, it is linked to maternal age [1] [2]. Significant bias on basis of race or ethnicity is not evident.

Patau syndrome is associated with a high rate of spontaneous abortion, intrauterine death, and a very short life span [3] [4]. Only 5% to 10% of neonates survive past the first year [3].

Gender: Males have a decreased prognosis of survival compared to females, both at birth and later in life [5] [6].

Age: Patau syndrome is a congenital syndrome, and is present prenatally. It may be diagnosed prenatally or at birth.

The most frequent form of Patau syndrome is free trisomy 13 [7], in which all cells of the neonate contain an extra copy of chromosome 13. In a rarer type of trisomy 13, called mosaic trisomy 13, some cells of the neonate’s body contain three copies of chromosome 13, while some are normal.

Robertsonian translocation of chromosome 13 to another chromosome constitutes of the third and the rarest type of trisomy 13 found in neonates with Patau syndrome.

There is no guideline for the prevetion of Patau syndrome.

Patau syndrome, more specifically known as trisomy 13, is a severe condition of newborns who have an extra copy of chromosome 13. It is characterized by structural defects, poor neurological performance, heart anomalies and other conditions at birth. Although rare compared to other trisomies, it is untreatable and holds a poor prognosis for the newborn.

Patau syndrome is a genetic defect that presents at birth as physical, neurological, cardiac, ocular, renal and genital defects due to an extra copy of chromosome 13. It is very rare. It is not an inherited disease, although some of its variants have a higher risk of recurrence. Prognosis is very poor, as many children are stillborn or die within few days of birth. There is no cure for a child with Patau syndrome, but you can prevent recurrence by prenatal screening and karyotyping of future children at fetal stage.

What are the symptoms of Patau syndrome?

The symptoms are always present at birth. Children with Patau syndrome suffer from severe mental retardation, heart defects, physical deformities and other problems that make their bodies incompatible to survive. Physically, they may exhibit:

• Microphthalmia (one or both eyes smaller than normal)
• Cleft palate (a split in the roof of the mouth)
• Polydactyly (more than normal number of fingers or toes)

These three signs make up the triad of Patau syndrome. However, it should be noted that all three signs may not be present in a child suffering from Patau syndrome.

What causes this disorder?

Patau syndrome is caused by an extra copy of chromosome 13. A normal human has 23 pairs of chromosomes, i.e. only two copies of chromosome 13. A child with Patau syndrome, however, has three copies of chromosome 13 (trisomy 13).

The most common variant of trisomy 13 is free trisomy 13. Like the name suggests, the extra chromosome is not attached to another, and is present in all cells of the child. This is the most severe variant of Patau syndrome, but has a very low risk of recurrence.

The less severe variants are partial trisomy 13 and Robertsonian translocation. In partial trisomy 13, not all cells of the child have three copies of chromosome 13 while in Robertsonian translocation, only a part of the extra chromosome 13 is present as an attachment to another chromosome. Although both these variants are less severe, they have more risk of recurrence. Hence, if your child has been diagnosed with one of these two variants, there’s a high chance that your next child may also suffer from Patau syndrome.

How is it diagnosed?

Patau syndrome is diagnosed through:

• Physical exam – Your doctor will perform a physical examination of your child. Most signs are evident on physical exam. However, your doctor will recommend further tests before giving a final diagnosis of Patau syndrome. 
• Genetic test – Genetic testing is a definite way to diagnose the syndrome. It allows the doctor to analyze your child’s DNA. Depending on the results of this test, your doctor may recommend a genetic test to you and your partner.
• Once the diagnosis is confirmed, your doctor may recommend further tests to assess the severity of your child’s condition.
• Blood tests – Since the body of a child suffering from Patau syndrome is incompatible with life, the blood tests will help your doctor to keep a check on your child’s body. The tests will show any problem that threatens the life of your newborn, and will enable your doctor to address it appropriately. 
• Imaging studies – A child suffering from Patau syndrome does not only have physical malformations. There may be problems present inside the body, hidden from your eye. X-rays, CT scans and MRIs will help assess the condition of the internal organs of your child’s body.

What are the treatments for this disease?

There is no treatment available for Patau syndrome. Many children die before, or within a few days of birth. If your child has been diagnosed with Patau syndrome before delivery, you may choose to continue or terminate the pregnancy. Survivors suffer from severe mental retardation and health problems all their lives.
If your child had a free trisomy 13, it is rare that your next child would also suffer from Patau syndrome. However, if your child had one of the other two variants, i.e. partial trisomy 13 or Robertsonian translocation, the risk of your next child suffering from the same is high.

In the latter case, your doctor will recommend genetic testing and counseling for you and your partner. This will help you assess the risk, and prevent recurrence of Patau syndrome in your next pregnancy.

There are support groups for parents whose children had suffered from Patau syndrome. These may be helpful in reducing your anxiety and depression. Genetic counseling will help you get more information, and make an informed decision about your current or future pregnancies.

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3. Rasmussen SA, Lee-Yang CW, Quanhe Y, et al. Population-based analyses of mortality in trisomy 13 and trisomy 18. Pediatrics. 2003;111(4)
4. Lakovschek IC, Streubel B, Ulm B. Natural outcome of trisomy 13, trisomy 18, and triploidy after prenatal diagnosis. Am J Med Genet Part A. 2011; 155: 2626–2633.
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