History First identified as a cytogenetic First identified as a cytogenetic

syndrome in 1960.syndrome in 1960.

13

47,XX,+13

47,XY,+13

♀♂

1. An extra copy of chromosome 13.1. An extra copy of chromosome 13.

2. Mosaic 46,XY2. Mosaic 46,XY/47,XY,+13/47,XY,+13..

3. Robertsonian translocation with one of 3. Robertsonian translocation with one of

the acrocentric chromosome (13, 14,15, the acrocentric chromosome (13, 14,15,

21, 22).21, 22).

4. Structural chromosome abnormality i.e., 4. Structural chromosome abnormality i.e.,

duplication of a part of chromosome 13.duplication of a part of chromosome 13.

Nondisjunction during maternal Nondisjunction during maternal

meiosis I.meiosis I.

Strong association exists betweenStrong association exists between

Patau syndrome and increasedPatau syndrome and increased

maternal age.maternal age.

Patau syndrome is the least common and the Patau syndrome is the least common and the

most severe of the viable autosomal trisomies.most severe of the viable autosomal trisomies. 1 case per 8,000-12,000 live births.1 case per 8,000-12,000 live births. No racial or geographic differences.No racial or geographic differences. Median survival is fewer than 3 days.Median survival is fewer than 3 days.

Significant numbers of +13 end Significant numbers of +13 end

in spontaneous abortion, in spontaneous abortion,

fetal demise, or stillbirth.fetal demise, or stillbirth.

Mortality and Morbidity

Median survival age is Median survival age is 2.5 days..

Only 1 child in 20 surviving longer than 6Only 1 child in 20 surviving longer than 6

months.months.

Reports of adults with Patau syndrome areReports of adults with Patau syndrome are

rare.rare.

Clinical feature Highly variable.Highly variable. Mosaicism for trisomy 13 is Mosaicism for trisomy 13 is

associated with a milder degree associated with a milder degree

of severity.of severity.

Patau Syndrome (47, +13)Patau Syndrome (47, +13)

Clinical presentation Hernias. Hernias. Cleft lip.Cleft lip. Cleft palate. Cleft palate. Omphalocele. Omphalocele. Microcephaly. Microcephaly. Microphthalmia. Microphthalmia. Rocker-bottom feet. Rocker-bottom feet. Polydactyly (postaxial).Polydactyly (postaxial). Scalp defects (cutis aplasia). Scalp defects (cutis aplasia).

• A 7-year-old child A 7-year-old child with full trisomy 13.with full trisomy 13.

•survival beyond survival beyond the first year is very the first year is very rare.rare.

• He is He is deaf and and blind..

Rocker-bottom appearance feet

Cleft lip or cleft palate

Bilateral cleft lip

Cyclopia (single eye) with a proboscis (the projecting tissue just above the eye)

Trisomy 13

Polydactyly Polydactyly

Causes of death are

Cardiopulmonary arrest in 69%.Cardiopulmonary arrest in 69%. Congenital heart disease in 13%.Congenital heart disease in 13%. Pneumonia in 4%. Pneumonia in 4%.

Diagnosis Clinical presentation.Clinical presentation. conventional cytogenetics. conventional cytogenetics. Fluorescent in situ hybridization (FISHFluorescent in situ hybridization (FISH).).

Genetic counseling

Increased risk Pregnant patients aged 35 years or olderPregnant patients aged 35 years or older Patients whose ultrasonographic findings are Patients whose ultrasonographic findings are

consistent with of aneuploidy.consistent with of aneuploidy.Elect fetal karyotyping Chorionic villus sampling.Chorionic villus sampling. Amniocentesis. Amniocentesis. Termination of pregnancyOption for the patient with a fetus exhibiting Option for the patient with a fetus exhibiting trisomy 13 before 24 weeks’ gestation.trisomy 13 before 24 weeks’ gestation.

Genetic counselingRecurrence risks depend on the 1. Chromosome abnormality.1. Chromosome abnormality.2. Mother's age. 2. Mother's age.

Free standing trisomy 13 The recurrence risk is 0.5% above the mother's The recurrence risk is 0.5% above the mother's

age related risk.age related risk. Recurrence risks for structural rearrangements Recurrence risks for structural rearrangements

(Robertsonian) vary considerably, risks can be as (Robertsonian) vary considerably, risks can be as high as 100% in casesinvolving both copies of high as 100% in casesinvolving both copies of chromosome 13. chromosome 13.

Termination of pregnancy is an option for the Termination of pregnancy is an option for the patient with a fetus exhibiting trisomy 13 before patient with a fetus exhibiting trisomy 13 before 24 weeks’ gestation.24 weeks’ gestation.

Prevention

Prenatal diagnostic for Parent with structural changes.Parent with structural changes. subsequent pregnancy. subsequent pregnancy. Pregnant women with age risk. Pregnant women with age risk. Women who have had a parent is Women who have had a parent is

known to carry structural chromosome known to carry structural chromosome abnormalities involving chromosome 13.abnormalities involving chromosome 13.

Cardiovascular system

Cardiac defects occur in 80% of casesCardiac defects occur in 80% of cases Dextrocardia. Dextrocardia. Atrial septal defect. Atrial septal defect. Patent ductus arteriosus. Patent ductus arteriosus. Ventricular septal defect. Ventricular septal defect.

Presentation Newborns with Patau syndrome typically present in the Newborns with Patau syndrome typically present in the

neonatal period with low Apgar scores, and they may neonatal period with low Apgar scores, and they may have the following conditions:have the following conditions: Cleft lipCleft lip Cleft palate Cleft palate Polydactyly (postaxial) Polydactyly (postaxial) Microcephaly Microcephaly Rocker-bottom feet Rocker-bottom feet Microphthalmia Microphthalmia Scalp defects (cutis aplasia) Scalp defects (cutis aplasia) Omphalocele Omphalocele HerniasHernias

Stillbirth and in utero fetal demise are common Stillbirth and in utero fetal demise are common pregnancy outcomes.pregnancy outcomes.

Physical examination

Cardiac defects occur in 80% of cases. Cardiac defects occur in 80% of cases. Patent ductus arteriosus Patent ductus arteriosus Ventricular septal defect Ventricular septal defect Atrial septal defect Atrial septal defect Dextrocardia Dextrocardia

Brain does not divide completely Brain does not divide completely intohalvesHypotelorism intohalvesHypotelorism Microphthalmia Microphthalmia Anophthalmia Anophthalmia Absent or malformed nose or proboscis Absent or malformed nose or proboscis Severe clefting of the lip and/or palate Severe clefting of the lip and/or palate

Polycystic kidneys or other renal malformationsPolycystic kidneys or other renal malformations

FOLLOW-UPFOLLOW-UP Further Outpatient Care: Further Outpatient Care: Provide surviving children with Patau syndrome the Provide surviving children with Patau syndrome the

same care other children receive, including visual same care other children receive, including visual assessments, hearing evaluations by age 6-8 assessments, hearing evaluations by age 6-8 months, and immunizations. Treat health problems months, and immunizations. Treat health problems according to severity and always in the best according to severity and always in the best interests of the child.interests of the child.

Specific growth charts are available for monitoring Specific growth charts are available for monitoring growth of children with Patau syndrome.growth of children with Patau syndrome.

Continue monitoring for apneic episodes.Continue monitoring for apneic episodes. Babies with Patau syndrome are notably irritable.Babies with Patau syndrome are notably irritable. Older children are at risk of developing scoliosis.Older children are at risk of developing scoliosis. In/Out Patient Meds:In/Out Patient Meds: Prior to dental procedures, administer prophylactic Prior to dental procedures, administer prophylactic

antibiotics for children with cardiac anomalies.antibiotics for children with cardiac anomalies.

Deterrence/Prevention:Deterrence/Prevention: In each subsequent pregnancy, offer a In each subsequent pregnancy, offer a

prenatal diagnostic study to women who prenatal diagnostic study to women who have had a pregnancy with an autosomal have had a pregnancy with an autosomal aneuploidy, including trisomy 13, 18, or aneuploidy, including trisomy 13, 18, or 21. Such studies are also indicated when 21. Such studies are also indicated when either parent is known to carry structural either parent is known to carry structural chromosome abnormalities involving chromosome abnormalities involving chromosome 13.chromosome 13.

Prognosis:Prognosis:

Prognosis is generally quite poor for the neonate Prognosis is generally quite poor for the neonate identified with Patau syndrome. Median survival identified with Patau syndrome. Median survival is only 2.5 days, 82% die within 1 month, and is only 2.5 days, 82% die within 1 month, and 95% die within 6 months.95% die within 6 months.

Patient Education: Patient Education: Although those who survive Patau syndrome Although those who survive Patau syndrome

have low educational potential, increased have low educational potential, increased stimulation and interaction are appropriate to stimulation and interaction are appropriate to maximize developmental potential.maximize developmental potential.

Medical/Legal Pitfalls:Medical/Legal Pitfalls:

Termination of pregnancy is an option Termination of pregnancy is an option for the patient with a fetus exhibiting for the patient with a fetus exhibiting trisomy 13 before 24 weeks’ gestation. trisomy 13 before 24 weeks’ gestation.

Recurrence risks in patients with Recurrence risks in patients with

structural chromosome rearrangements. structural chromosome rearrangements. Recurrence risks for future pregnancies Recurrence risks for future pregnancies

must be addressed in all cases. whether must be addressed in all cases. whether aneuploidy or structural rearrangements aneuploidy or structural rearrangements are involved.are involved.

Special Concerns:Special Concerns: Inform parents about the Inform parents about the

Support Organization for Trisomy 18, 13, and Related Disorders

Patau syndrome is the leastPatau syndrome is the least

common and the most severe common and the most severe

of the viable autosomal trisomies.of the viable autosomal trisomies.

RiskPregnant patients aged 35 years or Pregnant patients aged 35 years or

older and patients whose ultrasonographicolder and patients whose ultrasonographic findings are consistent with increased risk findings are consistent with increased risk

of aneuploidy often elect fetal karyotyping of aneuploidy often elect fetal karyotyping through chorionic villus sampling or through chorionic villus sampling or amniocentesis. Termination of pregnancy amniocentesis. Termination of pregnancy is an option for the patient with a fetus is an option for the patient with a fetus exhibiting trisomy 13 before 24 weeks’ exhibiting trisomy 13 before 24 weeks’ gestation. gestation.