The number of chromosomal diseases is huge and one of them is Patau's syndrome. The karyotype of a patient with a similar diagnosis is changed, which is reflected in the work of the whole organism. Pathology affects the structure of the skeleton, the work of the nervous, excretory, reproductive and cardiovascular systems.
Many parents today are interested in any additional information about this pathology. What is Patau Syndrome? Karyotype and phenotypic characteristics, methods of diagnosis and treatment, symptoms and causes are all interesting points. Such questions are worth exploring in more detail.
Patau syndrome: karyotype and general information
First, let's look at the general data. What is Patau syndrome and how does it develop? Chromosomes with such a pathology do not diverge during the formation of gametes or zygotes, which leads to a lot of disorders in the process of embryonic development.
Patau Syndrome is a congenital disease thatdue to trisomy of the 13th pair of chromosomes - the child receives an extra chromosome. The karyotype formula in this case may look like this: 47, XX, 13 + (for girls), 47, XY, 13 + (for boys). This is an extremely dangerous and serious disease, which is accompanied by the formation of multiple malformations - often they are not compatible with life, so the child dies in the womb.
Brief historical background
For the first time the symptoms of this pathology were described in 1657 in the works of the Danish scientist Erasmus Bartholin. Nevertheless, the chromosomal nature of the disease was proved by Dr. Klaus Patau in 1960 (the syndrome was named after him).
Cases of similar congenital pathologies have been described by scientists who have studied the tribes of the Pacific Islands. It is believed that the increased chromosomal mutations in this geographic area were caused by radiation damage following nuclear weapons tests.
Causes of disease development
As already mentioned, Patau syndrome is characterized by trisomy of the thirteenth pair of chromosomes. Moreover, in most cases (according to statistics, in 80%), non-disjunction of the thirteenth chromosome occurs precisely in the process of meiosis. Most often, a child receives a full pair of chromosomes from the mother. Sometimes there is a Robertsonian translocation, in which the embryo already receives an additional copy of the genes.
It has been proven that genetic failure can occur during the formation of a gamete or later - during the formation of a zygote.
To date, the causes of the appearance of a mutation are notestablished - it is believed that it occurs absolutely by chance. The role of infections, bad habits, somatic diseases of the mother in the development of this pathology in the fetus is also unknown.
Types of pathology
Today, there are several forms of this disease.
- A simple shape. In this case, violations occur in the early stages of embryonic development. Moreover, each cell of the body contains an extra chromosome in the thirteenth pair.
- Mosaic shape. Similar changes occur already at later stages of fetal development. At the same time, some organs consist only of he althy cells, while other tissues and organs contain pathologically altered cells. With this form of the disease, the symptoms may be less pronounced.
Are there risk factors? What can trigger a mutation?
Patau syndrome develops spontaneously and, alas, it is impossible to prevent it. Nevertheless, scientists have identified several adverse factors.
- It is believed that the risk of such a pathology increases if the mother lives in an area with a poor environmental situation.
- As already mentioned, radiation exposure plays a certain role in the appearance of spontaneous chromosomal mutations.
- It has also been observed that the likelihood of various chromosomal and genetic mutations increases in case of late pregnancy (mother over 45).
- Risk factors include the presence of hereditary diseases inprevious generations of parents.
- It has been proven that cases of genetic and chromosomal mutations are more frequent when it comes to marriages between close relatives.
Symptoms of pathology during pregnancy
As already mentioned, the karyotype formula in Patau syndrome is changed, but it is impossible to detect this without special tests. Nevertheless, often such a pregnancy is accompanied by polyhydramnios. According to statistics, the gestation time is also reduced - on average it is about 38.5 weeks. It is worth noting that with such a pathology, pregnancy is often interrupted. There is a high risk of stillbirth.
Patau Syndrome: Photos and Features
Children with this mutation have a number of special phenotypic characteristics. To begin with, it is worth saying that babies give birth on time, but with low weight - prenatal malnutrition occurs (the weight of a full-term baby with a similar diagnosis rarely exceeds 2500 g). The very process of childbirth is also often associated with complications, in particular, asphyxia of the newborn.
A child with a chromosomal mutation has a number of congenital deformities of the brain and facial part of the skull. There is microcephaly - the circumference of the baby's head is much less than normal. In children with Patau syndrome, the forehead is often low and sloping, the bridge of the nose is flat and sunken, and the palpebral fissures are narrow. The auricles are usually deformed and low.
A typical symptom is the presencebilateral clefts of the face, in particular, the so-called cleft palate (the pathology is accompanied by splitting of the tissues of the soft and hard palate, and the nasal and oral cavities are interconnected), as well as the "cleft lip" (cleft lip). A doctor may suspect the presence of this chromosomal mutation already in the first few hours after the birth of a child.
Pathology from other organ systems
What other disorders accompany Patau's syndrome? Signs of facial deformities are by no means the only ones. The disease affects almost all organ systems, causing severe birth defects.
- Many children have disorders of the central nervous system and visual analyzers. Possible hydrocephalus, hyloprochencephaly, dysgenesis of the corpus callosum, as well as the formation of spinal hernias. Possible complications include deafness, congenital forms of cataracts, retinal dysplasia, a decrease in the number of axons in the structure of the optic nerve, which leads to serious visual impairment.
- Possible congenital heart defects, including patent aortic duct, coarctation of the aorta, ventricular and atrial septal defects.
- Many babies are born with kidney defects. For example, patients are diagnosed with hydronephrosis, polycystosis, as well as a pathology called the “horseshoe kidney.”
- Abnormal changes in the digestive tract are possible. Their list includes the formation of Meckel's diverticula, cystic neoplasms in the tissues of the pancreas, incomplete bowel rotation.
- The mutation also affects the organs of the reproductive system. In boys, a delay in lowering the testicles into the scrotum (cryptorchim), as well as a displacement of the external opening of the urethra, is possible. In newborn girls, hypertrophy of the labia and clitoris is often observed, the formation of a bicornuate uterus, or even the formation of two separate uteruses and vaginas.
- Pathology affects not only the bones of the skull, but also other structures of the skeleton. For example, children with Patau syndrome often have polydactyly (appearance of extra fingers on the feet and hands) and syndactyly (fusion of fingers).
- All children with this disease suffer from severe forms of physical and mental retardation.
As you can see, this chromosomal pathology has dangerous and severe consequences, so the prognosis for children is unfavorable.
Diagnostic measures
Is it possible to detect such a disease as Patau's syndrome during fetal development? Diagnosis at this stage is certainly possible. As already mentioned, the pathology is accompanied by the occurrence of certain symptoms during pregnancy.
As a rule, the presence of such a mutation is suspected during an ultrasound scan. The specialist may note an increase in the volume of amniotic fluid, as well as the presence of abnormalities in the anatomical structure of the skeleton, the absence of hair in the fetus, low fetal body weight, etc.
In the future, genetic studies of hereditary material are carried out, because, as you know, the karyotype of a patient with Patau syndrome differs fromnormal. The following tests are informative.
- Amniocentesis - collection and further analysis of amniotic fluid.
- Cordocentesis - the essence of the technique is to obtain cord blood samples with its further laboratory examination.
- Chorion villus biopsy is a procedure that involves the collection of villi using a special probe. This test is prescribed for women with suspected Down syndrome, Patau and other chromosomal mutations.
It is worth noting that such research is associated with risks (for example, there is a possibility of losing a child). After the baby is born, the diagnosis is confirmed after examination by a neonatologist or pediatrician.
Is there an effective treatment?
You already know what Patau syndrome is. The karyotype of a child with such a diagnosis is changed, which affects the structure and functioning of the whole organism. Unfortunately, the possibilities for therapy are very limited. Sometimes surgery is performed to correct anatomical abnormalities (such as facial clefts).
The child should be constantly observed by a pediatric cardiologist, neurologist, ophthalmologist, urologist, ENT specialist, orthopedist, geneticist and other specialists. The baby needs to provide good care and good nutrition. Depending on the presence of certain disorders, symptomatic therapy is carried out.
Prognosis for little patients
Today, it is considered extremely dangerousPatau syndrome. The karyotype of a child cannot be changed and the prognosis for children is extremely unfavorable. Pregnancy often ends in miscarriage.
If the baby is still born, then, according to statistics, rarely lives to one year. Only in some developed countries, doctors and parents have the opportunity to extend the life of a child up to 4-5 years. Unfortunately, today medicine cannot offer effective methods of prevention or treatment.
