Trisomy Disorders

Trisomy 13

Posted on: October 30, 2008

Illustrations Polydactyly - an infant's hand Polydactyly – an infant’s hand Syndactyly Syndactyly

Alternative names    Return to top

Patau syndrome

Definition    Return to top

Trisomy 13 is a syndrome associated with the presence of a third (extra) number 13 chromosome.

Causes, incidence, and risk factors    Return to top

Trisomy 13 occurs in about 1 out of every 5,000 live births. It is a syndrome with multiple abnormalities, many of which are not compatible with life. More than 80% of children with trisomy 13 die in the first month.

Trisomy 13 is associated with multiple abnormalities, including defects of the brain that lead to seizures, apnea, deafness, and eye abnormalities.

The eyes are small with defects in the iris (coloboma ). Most infants have a cleft lip and cleft palate, and low-set ears. Congenital heart disease is present in approximately 80% of affected infants. Hernias and genital abnormalities are common.

Symptoms    Return to top

Signs and tests    Return to top

The infant may have a single umbilical artery at birth. There are often signs of congenital heart disease:

Gastrointestinal x-rays or ultrasound may reveal abnormal rotation of the internal organs.

MRI or CT scans of the head may reveal a structural abnormality of the brain, called holoprosencephaly, where the 2 cerebral hemispheres are fused.

Chromosome studies show trisomy 13, partial trisomy, trisomy 13 mosaic, or translocation.

Treatment    Return to top

Because of the severity of congenital defects, life-sustaining procedures are generally not attempted.

Support Groups    Return to top


Support Organization for Trisomy 18, 13 and Related Disorders (SOFT) —


Expectations (prognosis)    Return to top Extremely short survival time is expected. Rarely, affected persons survive to adulthood.

Complications    Return to top

Complications begin almost immediately. They include breathing difficulty or lack of breathing (apnea), deafness, vision problems, feeding problems, seizures, heart failure, and others.

Calling your health care provider    Return to top

Call for an appointment with your health care provider if you have had a child with Trisomy 13, and you plan to have another child.

Prevention    Return to top

Trisomy 13 can be diagnosed prenatally by amniocentesis with chromosome studies of the amniotic cells. Trisomy 13 mosaicism and partial trisomy 13 also occur. Parents of infants with trisomy 13 caused by a translocation should have genetic testing and counseling, which may help them prevent recurrence.


Update Date: 4/20/2005

Medline Plus


Trisomy 13 Facts

Trisomy 13 syndrome is a disorder of human chromosomes which occurs in approximately 1 in 10,000 live born infants. Trisomy 13 is due to the presence of an extra #13 chromosome. Approximately 80% of infants with Trisomy 13 syndrome will have a full trisomy while the remainder will have a trisomy due to a rearrangement called a translocation or have mosaicism (two different cell lines).

Infants born with Trisomy 13 have a recognizable pattern of physical features that often allow the health professional to make the diagnosis of the syndrome. Notable physical birth defects and sometimes, anatomic changes of internal organs are present. Findings of significance include small head size (microcephaly); small eyes (microphthalmia) or sometimes absent eye or faulty development of the retina. Cleft lip or cleft palate or both occur in about 60% of children. In addition, there are a number of less medically significant physical findings that are helpful in diagnosis. These include variations of ear shape, changes on the palm of the hand, and extra fingers and toes. Changes in foot development, including changes to the heel, the so-called rocker bottom foot, can occur.

Heart Defects

About 80% of children with Trisomy 13 will have a congenital heart defect. These can include: ventricular septal defect – an opening between the lower chambers of the heart which prevents the heart from pumping blood correctly (a heart murmur is generally heard from this finding); atrial septal defect – an opening between the two upper chambers of the heart making it difficult for the heart to pump sufficient oxygen rich blood to body tissues (a heart murmur is often heard); patent ductus arteriosis – a defect involving the lack of closure of the channel that usually closes near the time of birth; dextrocardia – location of the heart on the right side of the chest; on occasion more medically serious heart defects can occur in Trisomy 13.

Synonyms:       Trisomy 13

                        Patau Syndrome

                        Trisomy 13-15

D Trisomy Syndrome

 (these last two terms are usually not used at the present time)

Medical Problems

 The major implications of Trisomy 13 involve a predisposition to congenital malformations (birth defects) mentioned above, an increased mortality in infancy, and a developmental disability in older children. In addition, older infants can have visual difficulties because of the findings mentioned above and a hearing loss. The increased mortality is related to difficulties with breathing due to either interrupted breathing (apnea), or problems of lung development. In addition, gastroesophageal reflux and feeding problems can occur and predispose to aspiration adding to this risk. Usually the heart defects are not serious enough to be a major health threat in the newborn period.

Important and Common Birth Defects in Trisomy 13

Omphalocele Holoprosencephaly 60% (an anatomic defect of the brain involving failure of the forebrain to divide properly)

Kidney Defects 30%Skin defects of the scalp 20%

Common Disorders in infants and young children with Trisomy 13

feeding difficulties

gastroesophageal reflux

slow post natal growth

apnea seizures


kidney defects

developmental disabilities


Routine Follow-up care of infants with Trimsomy 13

Routine child care/anticipatory guidance

Cardiac evaluation

Eye evaluation

Hearing test Referral for Infant pre-school/early childhood intervention program

Referral for Infant pre-school/early intervention program

Ongoing support

Scoliosis check through childhood

Routine immunizations for immunization including chicken pox


Trisomy 13 Mosaicism

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