Patau Syndrome



Bartholin-Patau syndrome, also called autosomal Trisomy 13, is a very severe condition first described by Dr. Klaus Patau in 1960. This genetic disorder is associated with severe intellectual disability and physical abnormalities in many parts of the body. The affected individuals often have heart defects, brain or spinal cord abnormalities, microphthalmia (very small or poorly developed eyes), cleft lip, extra fingers and/or toes, among other features.

Causes
Trisomy 13 is a chromosomal condition in which the sex ratio at birth is slightly higher in females than in males. This fact could be related to the decreased survival rate among male fetuses.

Like most other trisomies (aneuploidy), Patau syndrome increasing incidence is associated with advanced maternal age, and the additional chromosome usually arises from nondisjunction in maternal meiosis resulting in three copies of 13 chromosome genetic material. This is a noninheritate case, is the result of random events during meiosis.

The extra genetic material disrupts the normal course of development, causing the characteristic features of trisomy 13. However, some cases derived from germinal mosaicism or by balanced chromosomal rearrangements (Robertsonian translocations), where the extra material is attached to another chromosome, are situations in which the trisomy can be inherited.

The person who carries the balanced translocation involving chromosome 13 has an increased chance of passing extra material from chromosome 13 to their children.

Symptoms
The small percentage of babies with full Patau's syndrome and who survived birth, may express the following internal and external conditions:
 * Low Apgar scores.
 * Hands and feet showing polydactyly (postaxial).
 * Facial defects:
 * Mouth: cleft lip and/or palate.
 * Nose: absent, malformed or proboscis (prominent).
 * Ears: malformed ears.
 * Eye: structural eye defects (microphthalmia, iris coloboma or even absence of the eyes).


 * Hands: abnormal palm pattern.
 * Muscle: Hypotonia (decreased muscle tone).
 * Hernias: umbilical hernia, inguinal hernia.
 * Severe central nervous system malformation:
 * Severe mental retardation.
 * Cephalic disorder: arhinencephaly and holoprosencephaly.
 * Spinal cord defects.


 * Cardiac defects.
 * Urogenital defects:
 * Abnormal genitalia (e. g. undescended testicle).
 * Kidney defects.

Diagnosis
Prenatal diagnosis is possible by amniocentesis, with the study of amniotic cells’ chromosome. Detected patients with fetus affected by trisomy 13 caused by a translocation, should have genetic testing counseling with a care provider. The specialist may give parents the information about recurrence risk, screening, and diagnostic testing options for future pregnancies. This pregnancy management varies according to the gestational age at diagnosis.

Recurrence risk
The recurrence risk is low. Even when one parent of translocation patient is carrier of the translocation in chromosome 13, the risk for the liveborn child to get the syndrome is still minimum (less than 1%).

Patau’s syndrome incidence figures is shown approximately 1 out of every 10,000 newborns and convey a very poor prognosis, with only 10% of affected infants living past their first year (mortality rate is very high among neonates culminating mainly in miscarriages).

Treatment
Each affected patient is a particular case with particular conditions, so the medical management focuses on the particular physical problems with which each child is born.

In the presence of congenital heart disease, for example, the surgery may be necessary to repair those defects. To minimize the neurological effects such as retardation, the patient can be given physical, occupational, and speech therapy (considering the child reaching childhood).

Related articles

 * Turner syndrome
 * Klinefelter syndrome