Trisomy 13, also known as Pätau syndrome, is a rare genetic defect in which chromosome 13 occurs three times instead of the usual two. It leads to a variety of different diseases and physical characteristics, most of which result in death in early childhood. Trisomy 13 is one of the best known triple abnormalities after Down syndrome and trisomy 18.
What is trisomy 13?
In a person with trisomy 13, chromosome 13 is present in triplicate. Thus, he or she has 47 chromosomes instead of 46. Different types of Pätau syndrome are distinguished. This depends on whether all cells of the organism are affected by trisomy 13 or only a part. The expression of the defects resulting from the trisomy varies. It includes growth disorders as well as supernumerary fingers or toes or malformations of the face. If trisomy 13 occurs, the life expectancy of the affected child is drastically shortened. Only a few reach an age of more than 10 years. Most children with trisomy 13 die within weeks or months after birth.
Causes
The causes of trisomy 13 are ostensibly due to abnormal chromosome division. This does not yet explain how this abnormality occurs. There is evidence that the occurrence of trisomy 13 may be linked to the increased age of the child’s mother. Depending on the type of trisomy 13, there are already indications of a form of trisomy 13 in the mother’s genetic material. The symptoms of Pätau syndrome are caused by the supernumerary chromosome in varying degrees. They are least pronounced in the case of mosaic trisomy 13. In this variant, there is a lack of separation of chromosome pairs and formation of three chromosomes in one cell only in a part of the cells. The course is similarly attenuated in partial trisomy 13, in which chromosome 13 is only partially altered in the cells of the embryo during pregnancy.
Symptoms, complaints, and signs
The disease causes numerous symptoms, both in appearance and internal organs. The common appearance of three signs is considered characteristic. The first is cleft lip and palate, in which a cleft extends through the upper jaw, upper lip, and palate. Colloquially, this malformation is called harelip. The second sign is microcephaly (small head) and micropthalmia (small eyes). The small head has an abnormal skull shape and causes reduced growth of the brain. The small eyes often have reduced development, and there may be defective vision or blindness. Fusion of the two eyes into a single one is also possible (cyclopia). The third symptom of the triple complex is additional fingers or toes (polydactyly). Usually a sixth limb is present on the hands or feet, so that twelve fingers or twelve toes are present. In addition to these typical signs, the heart may also be malformed. A ventricular septal defect is common, in which there is damage to the septum between the chambers of the heart. It can lead to enlargement of the heart and pulmonary hypertension. The ears are abnormally low and the nose is flat or absent. Furthermore, malformations of the cranial nerves, brain, kidneys, bladder, reproductive organs, blood vessels and skeleton are among the symptoms of the disease.
Diagnosis and course
Paetau syndrome can be detected during pregnancy. During prenatal diagnosis, the gynecologist examines abnormalities in the development of the fetus. If he or she detects special features that are particularly characteristic of a Pätau syndrome, a chromosomal analysis follows, as is also done if Down syndrome is suspected. Indications of Pätau syndrome include, in particular, heart defects in the fetus or developmental abnormalities and abnormalities in the amniotic fluid of the pregnant woman. The prognosis for a child born with trisomy 13 is poor. Mortality is very high in the first weeks of life. The malformations are often life-threatening, affecting not only the extremities but also internal organs such as the heart and kidneys. Trisomy 13 is considered a medical reason for abortion.
Complications
Trisomy 13 generally results in a number of different malformations and deformities on the body of the affected individual.The patients also suffer from severe disorders of growth and development. Immediately after birth, the children suffer from severe underweight and also from a developmental disorder of the brain. This leads to mental retardation and severe limitations in everyday life. Most of those affected are dependent on the help of other people in their daily lives due to trisomy 13. In some cases, the disorder also causes affected individuals to have six fingers. Particularly in childhood, the condition can lead to bullying or teasing due to the deformities, causing psychological distress. As a rule, parents and relatives also suffer from severe psychological discomfort in the case of trisomy 13. Due to the malformations of the internal organs, the life expectancy of the child is also significantly reduced. Since a causal treatment of the syndrome is not possible, only the symptoms are treated. No particular complications occur. Frequently, the diagnosis of trisomy 13 leads to termination of pregnancy.
When should you go to the doctor?
The affected person must contact a doctor in any case of trisomy 13. With this disease, there can be no self-healing, so medical treatment must always be given. The earlier the disease is detected and treated, the better is usually the further course. In most cases, however, the disease causes the death of the affected person already in childhood. Therefore, especially the parents and the relatives are dependent on a psychological treatment, so that no depression or other psychological upsets occur. A doctor should be consulted in the case of trisomy 13 if the affected person suffers from a facial malformation. In this case, the head of the affected person is usually also very small, and the eyes are also significantly reduced in size. Furthermore, a malformation of the heart may also indicate the disease and must be examined by a physician. The disease can be detected by a pediatrician. However, further treatment is carried out by a specialist. If there is a further desire to have children in the parents, genetic counseling should also be performed to prevent the recurrence of trisomy 13.
Treatment and therapy
Treatment for trisomy 13 depends on the defects present in each individual case. Because of the high mortality rate, symptoms are usually only relieved. If children with trisomy 13 are born alive, medical care must always be individualized. In Pätau syndrome, malformations in the form of cleft lip and palate are common. Increasing speech is one of the necessary therapies. In addition, there is movement therapy and social and psychological support for parents who are faced with caring for the children. However, surgical interventions to correct the deformities in paetau syndrome are still rare. However, there is a change in medical treatment. As a result, the life expectancy of children suffering from trisomy 13 is increasing, although it is not yet considered to be particularly high.
Prevention
If trisomy 13 is detected in time before birth, the question of terminating the pregnancy often arises. However, true prevention to prevent trisomy 13 is not possible because its development is beyond the parents’ control. On the other hand, the probability of recurrence of trisomy 13 in a new pregnancy is only slightly increased.
Follow-up
Because the life expectancy of children with trisomy 13 is low, psychological support for parents and other family members plays an important role in follow-up care. Through empathetic and professional support, the difficult situation can be better managed by all involved. The care of parents and siblings should not stop even after the death of the affected child. How long aftercare makes sense cannot be determined in a generalized way. It depends on the individual family situation and the wishes of the relatives. The primary goal of medical aftercare is to provide the best possible quality of life for children with Pätau syndrome. Existing physiological defects should be examined regularly. In this way, it can be detected at an early stage if the patient’s condition deteriorates.If another pregnancy occurs after a woman has given birth to a child with trisomy 13, the risk of recurrence of this genetic defect is only slightly increased. Special measures are therefore not necessary. Nevertheless, many families take advantage of human genetic counseling to feel more secure. During a subsequent pregnancy, an amniocentesis can exclude the possibility of a recurrence of trisomy 13. However, those involved should always keep in mind that this testing also increases the risk of miscarriage.
What you can do yourself
It is important to know that trisomy 13 is not just about the child. The (expectant) parents must also be considered as sufferers in this difficult situation. Psychological support may be needed to help them cope better with the condition. In many medical facilities and special clinics, parents are therefore provided with a psychologist to accompany them. This makes it easier for many to enjoy the time they can have with their child. But already at the diagnosis of trisomy 13, many parents suffer from restlessness, sleep disturbances and deep sadness. However, so that they can still enjoy the limited time with their baby, small home remedies can lead to some relief for some. These include medicinal plants and herbs that have a calming effect. Lavender is particularly well known in this regard. Essential oils can also provide a bit of relaxation. It gives many parents a good feeling to know that they are not alone in their situation. There are various networks on the Internet for exchanging information. Here you can find reports of experiences during pregnancy and the time with the child. The association for family self-help LEONA e.V. offers a lot of information as well as a network, which enables the exchange with other affected parents.
