Patau Syndrome

Dr. Patau et al. reported trisomy 13 as the source of a specific clinical condition in 1960. “cerebral abnormalities, cleft palate, apparent anophthalmia, simian creases, hare lip, polydactyly, trigger thumbs, & capillary hemangioma” were initially described as the clinical syndrome. Patau syndrome can be diagnosed either during pregnancy or at birth.

Because of the higher frequency of nondisjunction, greater maternal age is a risk factor for trisomy 13. Yet, 20 percent of Patau syndrome is caused by an imbalanced translocation or, in rare cases, mosaicism. Several big investigations have revealed that patients with Patau syndrome have a dismal prognosis. Among live-born patients, the average duration of survival is 7 – 10 days, & 90% survive for less than a year.

Many cases of extended survival due to vigorous medical treatment have recently been reported. Long-term survivors of Patau syndrome are much less likely to suffer brain & cardiovascular abnormalities, which are often the main cause of the disease’s poor prognosis. Even in these examples of higher survival, these patients can expect significant disability.

Cytogenetic defects occur in 50 percent of fetal fatalities before twenty weeks of pregnancy and in 6% – 13% of stillborns. Fetal mortality occurs in 15 percent of clinically identified pregnancies. Trisomy 13 constitutes one of the most frequent trisomies, occurring in 1 in every 5000 births.

This is less prevalent than Down syndrome, which occurs in one out of every 700 babies. Edwards syndrome has a comparable incidence, occurring in roughly 1 in every 5000 births.

Patau syndrome is caused by an extra copy of chromosome 13. Because of the increasing frequency of nondisjunction in meiosis, greater maternal age is a potential risk for this disorder. This additional copy of chromosome 13 disrupts usual embryonic development and causes a variety of abnormalities.

Patau syndrome is caused by the presence of 3 copies of chromosome 13; this is most typically caused by nondisjunction in meiosis, which occurs more frequently in elderly women (above 35). An imbalanced Robertsonian translocation can also result in 2 regular copies of chromosome 13 & an extra-long arm of chromosome 13.

Mosaicism is a less common cause, resulting in three copies of chromosome 13 in certain cells & 2 copies in others. Mosaicism is caused by a mitotic nondisjunction mistake and has nothing to do with maternal age. Patients with mosaicism and imbalanced translocations have a better prognosis.

Numerous significant investigations have documented the relatively poor prognosis of Patau syndrome patients. Historically, the median survival time for live-born patients is between seven and ten days, & 90 percent do not survive one year. Recently, cases of longer-term survival have been described with the application of severe medical measures.

Individuals with mosaic Patau syndrome & imbalanced translocations have a better prognosis. According to a recent study, aggressive care with surgical & medicinal treatment may increase the survival rate to 733 days.

Clinical history

The clinical history of Patau syndrome typically includes the following:

Prenatal history: Patau syndrome is a chromosomal abnormality that is typically diagnosed prenatally through genetic testing. Women who are at higher risk for having a baby with Patau syndrome include those who are older, have a family history of chromosomal abnormalities, or have had a previous child with a chromosomal abnormality.
Physical characteristics: Babies with Patau syndrome often have distinct physical characteristics, including a small head (microcephaly), low-set ears, a small jaw (micrognathia), and small or malformed eyes (microphthalmia). They may also have cleft lip and palate, extra fingers or toes, and other abnormalities.
Developmental delays: Children with Patau syndrome typically have developmental delays, both physical and intellectual. They may have difficulty with motor skills, language development, and other developmental milestones.
Medical complications: Children with Patau syndrome may have a range of medical complications, including heart defects, breathing problems, seizures, and kidney problems. These complications can be life-threatening and require ongoing medical care.
Life expectancy: The life expectancy for children with Patau syndrome is typically short, with most children dying within the first year of life. However, some children with less severe forms of the condition may survive longer.

A comprehensive clinical history, along with genetic testing and medical evaluation, can help to diagnose and manage Patau syndrome effectively. Treatment options may include medical and surgical interventions to manage complications and improve quality of life.

Physical examination

The physical examination of Patau syndrome typically includes the following:

Measurement of the head circumference: Patau syndrome is associated with microcephaly or a small head size. The head circumference is measured and plotted on a growth chart to monitor for changes over time.
Evaluation of facial features: Children with Patau syndrome often have distinct facial features, including small or malformed eyes (microphthalmia), a small jaw (micrognathia), and low-set ears. The examiner will evaluate these features and may order additional imaging studies, such as a brain MRI, to evaluate for any associated brain abnormalities.
Assessment of physical development: Children with Patau syndrome often have developmental delays, including delays in motor skills, language development, and other developmental milestones. The examiner will evaluate the child’s physical development and may refer the child for further evaluation by a developmental specialist.
Examination of the heart: Patau syndrome is associated with a high incidence of heart defects, which can be life-threatening. The examiner will evaluate the child’s heart function through a physical exam and may order additional testing, such as an echocardiogram, to evaluate for any abnormalities.
Examination of other organ systems: Patau syndrome is associated with a range of medical complications, including breathing problems, seizures, and kidney problems. The examiner will evaluate other organ systems to monitor for any potential complications and may order additional testing or referrals to specialists as needed.

A comprehensive physical examination, along with genetic testing and medical evaluation, can help to diagnose and manage Patau syndrome effectively. Treatment options may include medical and surgical interventions to manage complications and improve quality of life.

Differential diagnosis

A fetus with Patau syndrome may show sonographic signs that correlate with Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), or even other genetic abnormalities.

Cytogenetic testing, such as chorionic villi sample, amniocentesis, tissue microarray, or fetal free DNA testing, would differentiate trisomy 13 from multiple different cytogenetic deficits.

Intensive therapy for Patau syndrome is debatable due to patients’ often poor prognosis despite therapy. Infants with Patau syndrome may require post-delivery ventilation and oxygenation, which may necessitate tracheostomy or intubation due to facial abnormalities. Individuals with common cardiovascular issues may require cardiac surgery to be repaired.

Additional surgeries, like herniorrhaphy, feeding tube installation, corrective orthopedic treatments, or cleft lip surgery, may be required for common problems. Specialized nutritional feeds, seizure prevention, preventive antibiotics for infections of the urinary system, and the usage of hearing aids are all possible treatments. Despite rigorous management, median overall survival in the most current patient cohorts is only 733 days.