What is Patau Syndrome ?
Patau syndrome is a genetic condition wherein there are three copies of the chromosome 13 instead of two copies.
Patau syndrome is a type of genetic abnormality in which a part of, or all of chromosome 13 appears 3 times in all the cells of the body, instead of two times. It is often known as ‘Trisomy 13.’ In some affected individuals only a percentage of the body’s cells may have the additional 13th chromosome, while the rest of the cells contain just the two pairs of the chromosome.
The extra chromosome leads to impaired development of the body which in turn results in physical deficits as well as intellectual abnormalities in the affected individual
Patau syndrome generally tends to occur only in 1 out of ten to sixteen thousand infants. Most of the affected children do not inherit the syndrome, but generally develop the condition due to random occurrences at the time of egg and sperm formation in healthy parents. Most of the babies with Patau syndrome die within the first few days or weeks after birth as a result of the medical complications that accompany the disorder. Only about 5 to 10 percent of the babies with Patau syndrome live beyond the first year of their lives.
Since the physical symptoms of Patau syndrome are very peculiar, it becomes easy for the health care providers to diagnose the condition. The physical defects are easily visible and on occasions there may be certain anatomical alterations of the internal organs in the baby. The child may be born with a tiny head; with vision abnormalities such as a damaged retina, an absent eye or tiny eyes; additional toes or fingers; a cleft lip or cleft palate; changes in palm or heel or foot development, and irregularly shaped ears.
Patau syndrome Symptoms
Patau syndrome patients may exhibit a number of abnormalities such as defects of the heart, irregularities of the spinal cord or brain, underdeveloped or small eyes, extra fingers or toes, cleft palate or cleft lip and diminished muscle tone.
The babies affected by Patau syndrome may experience feeding and swallowing difficulties, may not gain weight or grow as per the normal standards and may elicit temporary breathing problems such as apnea.
A majority of the affected babies experience congenital heart defects such as:
- Atrial septal defect which refers to the presence of a hole between the upper chambers of the heart. This poses difficulties for the heart to effectively pump the oxygen-rich blood to the different organs of the body.
- Ventricular septal defect which refers to the presence of an opening or a hole between the two lower chambers of the heart. This prevents the heart from effectively pumping the blood
- On occasions the heart may be located on the right side of the chest instead of the left side. This cardiac condition is known as dextrocardia.
- A particular channel in the heart normally closes just prior to birth. An incomplete closure of this channel results in ‘patent ductus arteriosis’ in babies with Patau syndrome
Some other symptoms of Patau syndrome include the following:
- Scalp defects which include skin abnormalities of the scalp
- Undescended testicle
- Clenched fist or hands
- Mental retardation
- Small lower jaw
- Single palmar crease
- Skeletal abnormalities
- The iris may be split or have a cleft or a hole. The eyes may be so close-set that it may seem as though they were fused together.
- Slow post natal growth
- Defects of the kidneys
- Presence of gastro-esophageal reflux
- The affected child may experience developmental disabilities
- Presence of high blood pressure
- Scoliosis on rare occasions
Causes of Patau syndrome
Patau syndrome is caused due to the appearance of an additional DNA of the chromosome 13 in some of all the cells of the affected individual’s body.
When the extra chromosome 13 is present in only some of the cells of the body, then the condition is referred to as ‘Mosaicism.’
When only a part of the extra chromosome 13 is present in the cells of the affected person, then the condition is known as partial Trisomy 13
The additional materials prevent the normal development of the child and are normally the cause of the characteristic symptoms and abnormalities of Patau syndrome. Most cases of the syndrome are not inherited from the parents. The events that result in Patau syndrome in the child, generally tend to happen in the sperm or the eggs that eventually develop into the fetus.
Most of the individuals with Patau syndrome posses the extra copy of the chromosome 13 in all the cells of the body, while the minority has the excess materials only in some body cells. The symptoms of Patau syndrome are milder in those with ‘mosaic’ Patau syndrome as compared to individuals with full blown cases of the disorder.
Patau syndrome treatment
- Patau syndrome is a life threatening disorder and a majority of the affected babies do not live beyond the first few weeks of their lives. Hence most of the treatment is aimed at managing the symptoms and prolonging the life of the baby.
- Surgical means to correct the defects associated with Patau syndrome, are delayed as much as possible, due to the high mortality rate of the affected infant.
- Screening methods during pregnancy are one of the best ways for early detection of the syndrome in the unborn child.
Patau Syndrome Pictures