Trisomy 8 is a genome mutation that results in a chromosomal aberration. The symptoms depend on the form of the mutation. Many trisomy eight patients show a mild course with relatively normal intelligence.
What is trisomy 8?
Trisomy 8 is a rare chromosome peculiarity that goes back to a genome mutation and occurs sporadically. The disease is also known as Warkany syndrome 2 and goes back to this name by the pediatrician Joseph Warkany, who first described the symptom complex in the 20th century. Since it was first described, only around 120 cases of trisomy 8 have been documented. For camptodactyly definition and meaning, please visit eshaoxing.info.
Chromosome eight trisomy is predominantly a mosaic mutation and affects both boys and girls. The symptoms are sometimes clearly pronounced before birth and can be seen in the prenatal ultrasound. There is always talk of a trisomy when there are three copies of the gene instead of two.
The symptoms of trisomy eight depend on the affected section of the chromosome and on the completeness of the trisomy and thus the respective subtype of the causative mutation. Severe trisomies are often associated with miscarriages. The affected fetus is therefore not capable of surviving in the case of a severe form of trisomy.
Causes
The primary cause of trisomy eight, like any other trisomy, is a genome mutation. This must be distinguished from gene mutations that do not change the number of chromosomes within the individual body cells. Gene mutations change the structure of the DNA because the order of the building blocks is changed. In the case of a genome mutation, on the other hand, the genetic material itself is changed and has an abnormal set of chromosomes.
A whole set of chromosomes may be missing, misaligned, or duplicated in each cell. The genome mutation is caused by defective cell division during the first or second meiotic division. This type of mutation can correspond to a partial mutation and in this case does not affect the entire genome.
The mutation can also correspond to a translocation and then results in the adhesion of an additional chromosome set to one of the other chromosome sets. On the other hand, when there is a mosaic mutation in the genome, two sister chromatids did not separate at mitosis and the trisomy is confined to certain cells of the body while other cells have a normal set of chromosomes.
Symptoms, Ailments & Signs
Many symptoms of trisomy 8 are already recognizable before birth. In addition to a heart defect and kidney malformation, these symptoms include, for example, the enlargement of the renal pelvis, tetramelia and scoliosis, lordosis or kyphosis. Block vertebrae, clinodactyly and camptodactyly can also be recognized before birth.
The same is true for characteristic mandibular retrognathia, brachydactyly, or patellar hypoplasia. The clinical picture is extremely variable, especially after birth, and depends primarily on the form of the trisomy. Generalizations are almost impossible.
Common symptoms are arthrogryposis, a so-called spina bifida occulta and abnormal plantar ridges or a sandal ridge, palmar ridges and four-finger ridges. Those affected often have low-set and large or long ears. Their antihelix is often underdeveloped. The forehead is high in many cases. In addition to a short neck, there may be narrow, sloping shoulders. The thorax is often exceptionally long.
The number and thickness of the ribs is abnormal. These symptoms can be associated with accessory nipples, a gothic palate or a cleft palate. Exceptionally full lips and an everted lower lip are just as much a part of the clinical picture as hypotelorism, ptosis or a strabismus. In most cases, there is also a mild to moderate impairment of cognitive abilities. Despite this long list of symptoms, there are trisomy patients who are almost asymptomatic throughout their lives.
Diagnosis & course of disease
Trisomy 8 can be diagnosed before birth. The fine ultrasound gives the first indications. However, a reliable prenatal diagnosis can only be made by analyzing the chromosomes. Amniocentesis or chorionic villus sampling can be done prenatally. However, a mosaic trisomy 8 can also be subject to local limitations.
All prenatal diagnostics of trisomy are considered uncertain and often result in falsely positive results. Postnatally, the diagnosis can be suspected depending on the clinical picture. The genetic analysis confirms the suspected diagnosis or excludes it. The prognosis depends on the proportion of triisomer and disomer cells. Mental and physical development often correlate in the course of the disease. A normal development is possible with a mild trisomy 8.
When should you go to the doctor?
Medical treatment is definitely necessary for trisomy 8. The affected person is dependent on early detection of the disease so that further complications and symptoms can be prevented. The earlier trisomy 8 is detected, the better the further course of this disease is in most cases. A doctor should be contacted if the person concerned suffers from a heart defect. This should always be checked through regular examinations.
Furthermore, limitations in intelligence can also indicate the disease and should be checked by a doctor. Some patients also suffer from squinting or other visual problems and therefore cannot easily participate in everyday life. Mental upsets or even depression can also indicate this disease.
In the case of trisomy 8, a general practitioner or a pediatrician should be consulted. In the further treatment, however, a visit to a specialist is also necessary in order to treat the symptoms correctly.
Treatment & Therapy
Trisomy 8 is still one of the incurable diseases. A causal therapy is basically not available for patients with trisomy, since any gene therapies have not yet been approved for treatment. Ultimately, incurable diseases can only be alleviated by symptomatic therapy. This symptomatic therapy depends on the symptoms present in the individual case.
The main focus of therapy is on deformities and loss of function in the vital organs. In the case of trisomy 8, the greatest attention is therefore initially paid to the heart defect. A surgical procedure can sometimes correct existing heart defects. Patellar agnosia can be corrected by reconstructive surgery to restore normal mobility.
Accumulation of fluid in the neck area can be drained and kidney deformities with functional limitations of the kidneys are treated with dialysis and later, if necessary, a transplant. The deformities of the face and fingers or toes can also be surgically resolved. However, this approach is not mandatory and does not have to take place immediately after birth.
Early support with the aim of normal mental development is more important. In mild forms of trisomy eight, the intelligence is usually not noticeably restricted and the patients may not have to undergo any surgical therapy steps.
Prevention
Preventive measures are not available for trisomy 8. After a prenatal diagnosis, however, parents can decide against the child.
Aftercare
Follow-up care for trisomy 8 is diverse. This is because the symptoms of the patients differ significantly in some cases. While some of the affected children have severe intellectual disabilities and require lifelong care, other patients are only mildly mentally impaired or even completely normal.
However, almost all children with trisomy 8 benefit from early support with ergotherapy and other measures. Follow-up care does not only include the treatment of the actual patients. Family members should also be closely involved. Parents sometimes need help from a domestic help or a caregiver, since caring for their own child can be very stressful.
Psychological support may also be appropriate in some cases. If the parents of a child with trisomy 8 wish to have another child, there is often concern that the defect could repeat itself. Comprehensive follow-up care therefore also includes advice for the parents from a human geneticist.
Although the risk of recurrence is usually low, existing fears should be taken seriously. If you become pregnant again, a chorionic villus biopsy or an amniotic fluid test can be used to determine whether there is a chromosomal disorder. However, such an operation poses an increased risk of miscarriage and should therefore be carefully considered.
You can do that yourself
People with trisomy 8 need constant support in everyday life. It is the task of relatives and acquaintances to support those affected in everyday life and to help them with everyday tasks. This not only includes aspects such as personal hygiene or mobility, but also emotional support.
Because trisomy 8 is associated with severe mental illnesses, depending on the severity, it may be necessary to talk to therapists and consult self-help groups. The reduced intelligence can be partially compensated by cognitive training. Brain jogging, autogenic training and a number of other measures that promote intelligence and healthy behavior are effective. In the event of external malpositions, surgical measures must be taken. It is important to initiate this at an early stage so that physical development can proceed as normally as possible. It is best for parents of affected children to contact the responsible specialist.
People with trisomy 8 usually require specialist care in a facility. The psychological complaints need to be treated with medication as well as with talk therapies, distraction and a number of other measures. The Association for Trisomy Patients provides those affected and their relatives with further information on the disease and points of contact for further advice.
