Patau syndrome: patient's karyotype, photo, diagnosis, causes, symptoms

The number of chromosomal diseases is huge and one of them is the Patau syndrome. Karyotype of a patient with a similar diagnosis is changed, which is displayed on 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 are now interested in any additional information about this pathology. What is the Patau syndrome? Karyotype and phenotypic characteristics, methods of diagnosis and treatment, symptoms and causes are all interesting moments. Such questions should be studied in more detail.

Syndrome Patau: karyotype and general information

To begin with it is necessary to understand the general data. What is Patau syndrome and how does it develop? Chromosomes in this pathology do not diverge in the process of formation of gametes or zygotes, which leads to a mass of disturbances in the process of embryonic development.

Patau syndrome is called an innate disease, which is associated with trisomy of the 13th pair of chromosomes - the child gets an extra chromosome. The karyotype formula in this case can look as follows: 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.

A Brief Historical Reference

The symptoms of this pathology were first described in 1657 in the works of the Danish scientist Erasmus Bartolin. Nevertheless, the chromosomal nature of the disease was proved by Dr. Klaus Patau in 1960( in his honor, the syndrome was named).

Cases of similar congenital pathologies have been described by scientists who have been studying the Pacific Islands tribes. It is believed that the rapid chromosomal mutations in this geographic region were caused by radiation damage that appeared after nuclear weapons tests.

Causes of the development of the disease

As already mentioned, the Patau syndrome is characterized by trisomy of the thirteenth pair of chromosomes. In most cases( according to statistics, in 80%), the nondisjunction of the thirteenth chromosome takes place precisely in the process of meiosis. Most often the child receives a full pair of chromosomes from the mother. Sometimes there is a Robertsonian translocation, in which already an embryo receives an additional copy of the genes.

It is proved that a genetic malfunction can occur during the formation of the gamete or later - during the formation of the zygote.

To date, the causes of the mutation have not been established - it is believed that it occurs absolutely randomly. Also, the role of infections, bad habits, and mother's somatic diseases in the development of this pathology in the fetus is unknown.

Types of pathology

To date, there are several forms of this disease.

• Simple form. In this case, violations occur in the early stages of embryo development. In this case, each cell of the body contains an extra chromosome in the thirteenth pair.
• Mosaic form. Similar changes occur already at later stages of fetal development. In this case, some organs consist only of healthy cells, while in other tissues and organs there are pathologically altered cells. With this form of the disease, symptoms may be less pronounced.

Are there risk factors? What can trigger a mutation?

Patau syndrome develops spontaneously and it is impossible to prevent it, alas. Nevertheless, scientists have identified several unfavorable 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 chromosome mutations.
• It is also noted that the likelihood of different chromosome and genetic mutations increases in the case of late pregnancy( mother over 45 years old).
• The risk factors include the presence of hereditary diseases in previous generations of parents.
• It is proved that cases of genetic and chromosomal mutations become more frequent when it comes to marriages between close relatives.

Symptoms of pregnancy pathology

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 many-water. According to statistics, the time of fetal gestation also decreases - an average of about 38.5 weeks. It is worth noting that with this pathology, pregnancy is often interrupted. There is a great risk of stillbirth.

Syndrome Patau: photos and distinctive features of

Children with a similar mutation have a number of special phenotypic characteristics. First of all, it should be said that babies give birth on time, but with a small weight - prenatal hypotrophy takes place( the weight of a full-term child with a similar diagnosis rarely exceeds 2500 g).The very process of delivery 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 cerebral and facial parts of the skull. There is microcephaly - the circumference of the baby's head is much less than the norm. In children with the Patau syndrome, the forehead is often low and skewed, the nose bridge is flat and sunken, and the eye slits are narrow. The ears are usually deformed and located low.

A typical symptom is the presence of bilateral facial clefts, in particular, the so-called wolf mouth( pathology is accompanied by cleavage of soft and hard palate tissues, with the nasal and oral cavities being communicated to each other), as well as the "hare lip"( cleft lip).The doctor may suspect the presence of this chromosomal mutation already in the first frequent after the birth of the child.

Pathology from other organ systems

What other disorders are accompanied by Patau syndrome? Signs of facial deformities are by no means unique. The ailment affects the work of almost all organ systems, causing severe congenital malformations.

• Many children experience disorders from the central nervous system and visual analyzers. Possible hydrocephalus, hyloproencephaly, dysbinesia of the corpus callosum, as well as the formation of spinal hernias. Possible complications include deafness, congenital cataract forms, retinal dysplasia, a reduction in the number of axons in the optic nerve structure, leading to serious visual impairment.
• Congenital heart defects, including open aortic duct, coarctation of the aorta, defects of the interventricular and interatrial septum are possible.
• Many children are born with kidney malformations. For example, patients are diagnosed with hydronephroses, polycystosis, and also a pathology called "horseshoe-shaped kidney".
• Abnormal changes on the part of the digestive tract are possible. To their list include the formation of diverticula Meckel, cystic neoplasms in the tissues of the pancreas, an incomplete turn of the intestine.
• Mutation affects the organs of the reproductive system. In boys, a delay in lowering the testicles into the scrotum( cryptorchyma), 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 the two-horned uterus or even the formation of two separate mares 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( the appearance of extra fingers on the feet and hands) and syndactyly( fusion of the 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 predictions for children are unfavorable.

Diagnostic measures of

Is it possible to detect such a disease during intrauterine development as Patau syndrome? Diagnosis at this stage is certainly possible. As already mentioned, the pathology is accompanied by the appearance of certain symptoms during pregnancy.

As a rule, suspicions of such a mutation appear during ultrasound. The specialist can note the increase in the volume of amniotic fluid, as well as the presence of abnormalities in the anatomical structure of the skeleton, the lack of hair in the fetus, the low fetal body mass, etc.

Genetic studies of the hereditary material are subsequently carried out, as is known, the karyotype of a patient with the Patau syndromediffers from normal. The following tests are informative.

• Amniocentesis is a fence and further analysis of amniotic fluid.
• Cordocentesis - the essence of the technique is to obtain umbilical cord blood samples with further laboratory testing.
• Chorionic villus biopsy is a procedure that involves the taking of villi with a special probe. This test is prescribed for women with suspected Down syndrome, Patau and other chromosomal mutations.

It should be noted that such studies involve a risk( for example, there is a probability of losing a child).After the birth of the baby, the diagnosis is confirmed after examination by a neonatologist or pediatrician.

Is there an effective treatment?

You already know about what constitutes the Patau syndrome. 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 surgical intervention is performed, which allows to eliminate anatomical abnormalities( for example, facial crevices).

The child should be constantly observed at the children's cardiologist, neurologist, ophthalmologist, urologist, ENT, orthopedist, genetics and other specialists. The baby needs to provide good care and adequate nutrition. Depending on the presence of certain violations, symptomatic therapy is performed.

Forecasts for small patients

To date, the Patau syndrome is considered extremely dangerous. Karyotype of a child can not be changed and forecasts for children are extremely unfavorable. Very often pregnancy ends in a miscarriage.

If the baby is still born, then, according to statistics, rarely lives up to one year. Only in some developed countries, doctors and parents have the opportunity to extend the life of the child to 4-5 years. Unfortunately, to date, medicine can not offer effective methods of prevention or treatment.