Patau’s syndrome
Introduction:
The syndrome, a chromosomal disorder caused by an error in cell division resulting on additional third chromosome 13, is known as Patau’s syndrome. Medical problems associated with Patau’s syndrome, occurs in approximately one among 12000 births. This is the most common syndrome after Down’s syndrome and Edward’s syndrome.
Human body cells contain 23 pairs of chromosomes inherited from parents. Human reproductive cells, the sperm cells in male and ovum in females each have 23 individual chromosomes, known as XX in females and XY in males and number 1 through 22. If after fertilization the egg contains extra material from chromosome 13, will cause Patau’s syndrome.
Variation of Edward’s syndrome:
Trisomy 13:
* Majority of Patau’s syndrome falls in this category. In a situation, where all cells of individual contains additional chromosome 13, is known as trisomy 13. This type of Patau’s syndrome (Trisomy 13) is not hereditary
Mosaic Trisomy 13:
* In mosaic trisomy 13, additional chromosome 21 may be present in some cells, but not in all the cells.
Partial & Translocation Trisomy 13:
- In partial trisomy only one part of extra chromosome is present. In some cases the partial trisomies may be translocated, .the additional chromosome 13 may stuck to another chromosome or additional chromosome may be translocated resulting in no increase in the number of chromosomes from 46. Translocational trisomies may be caused by parent’s translocation, and such trisomies may be hereditary.
Screening Test for Down’s syndrome in unborn child:
- AFP or quad screen test on pregnant mother is carried out to determine the increased likelihood of Patau’s syndrome in fetus.
- The targeted ultrasound is performed on pregnant mother (level 2) to diagnose the physical features of unborn child for Patau’s syndrome.
- If features like small head, cleft palate, heart defects are observed in ultrasound the further confirmatory tests are carried out.
- These tests are only indicative and may require further testing to confirm the Patau’s syndrome.
Confimatory Tets for Patau’s syndrome in Unborn Child:
- Amniocentesis: This test is required to be carried out during 14-18 week of pregnancy. A small amount of fetal cell is collected from amniotic fluid and examined.
- Chorionic Villus Sampling: Although this test carries a small amount of risk of miscarriage. A small amount of fetal tissue is collected during 9-11 week pregnancy and tested for additional or extra material chromosome 13.
Physical features of Down’s syndrome:
Physical features in children having Down’s syndrome include
- Abnormal face,
- Small head.
- Cleft palate.
- Defects in eye development or missing eye.
- Sloping forehead.
- Small birth weight.
- Deafness.
- Abnormal hands and feet with extra fingure.
- Heart problems including arterial and ventricular septal defects and patent ductus arteriosus.
- Breathing abnormalities.
- Low birth weight.
- Mental weakness.
- Abnormal feet.
Medical disorders:
- Patau’s syndrome is fatal and most of the babies die before taking birth.
- Babies with Patau’s syndrome do not survive for more than a few days except a few.
- Although there are reports that a few child has survived for longer period.
|
