Asphyxiating thoracic dysplasia is a short rib polydactyly syndrome. The patients’ narrow thorax usually causes thoracic respiratory failure. If affected individuals survive the first two years, the risk of death in the future is greatly reduced.
What is asphyxiating thoracic dyplasia?
Asphyxiating thoracic dyplasia is a skeletal dysplasia in the short rib polydactyly group of syndromes and is also called Jeune syndrome. This name goes back to the pediatrician M. Jeune, who first described the phenomenon in 1954. The congenital malformation of the thorax belongs to the ciliopathies. One to five affected persons per 500,000 newborns are given as a ratio for the occurrence. The disease is hereditary and is usually manifested by extremely short ribs and an extremely narrow thorax. Multiple organ involvement may be present, such as that of the liver and pancreas. Although the disease is usually associated with an unfavorable course, there are exceptions to this rule. After the second year of life, the worst is over.
Causes
Skeletal dysplasia Jeune syndrome is inherited in an autosomal recessive pattern. This means that the affected gene is located on an autosome. In genetics, a dominant allele always prevails over a recessive allele. For the disease to actually occur on a recessive autosome, both partners must have at least one recessive allele as a disease carrier. Jeune syndrome can occur through mutations of different genes. Not all genes are known yet. An involvement exists, for example, for the gene IFT80 (3q25.33). The same is true for the gene DYNC2H1 (11q22.3) and the gene WDR19 (4p14). A mutation of the gene TTC21B (2q24.3) is also now recognized as a possible cause of Jeune syndrome. Each of the above-mentioned genes codes for one flagellar transport protein. For this reason, the disorder is also classified as one of the so-called zilliopathies.
Symptoms, complaints, and signs
Affected individuals with Jeune syndrome have a long and narrow thorax. The horizontal roof of their pelvis is also striking. They usually suffer from shortness of breath from birth because their lungs have little room in the dysplastic thorax. This is called thoracic respiratory insufficiency. This means that the shortness of breath is caused by the lack of space in the chest. Often the patients’ lungs are even underdeveloped because of the minimal space. As with all other disorders from the group of short rib polydactyly syndromes, polydactyly, i.e., polydactyly, is present in many affected individuals. Other skeletal anomalies may occur. Short extremities and short stature are common. Later, renal insufficiency due to nephronophthisis often occurs. Retinopathy may also occur, which is a retinal disease. Jaundice and fibrocytic changes of the liver and pancreas also frequently occur as part of the disease.
Diagnosis and course
While the fetus is still in utero, the diagnosis of Jeune syndrome can be made by careful ultrasound examination. For the most common form of the disorder, there is also the possibility of prenatal diagnosis by molecular genetics. If this option is not used, the diagnosis is made immediately after birth by visual diagnosis and radiological findings. Jeune syndrome is fatal in many cases, although the less the internal organs are affected by dysfunction, the more favorable the prognosis. Depending on the ossification type of all cartilage systems, there are two different forms of the disease, also known as type I and type II. Ultimately, the impairment of the lungs determines how promising the treatment of asphyxiating throacic dysplasia is. After the second year of life, the risk for infection decreases significantly.
Complications
Asphyxiating thoracic dysplasia is the rare malformation of a chromosome. Affected individuals have a narrow long-acting thorax with short ribs from birth. Due to the physical restriction of the thorax, the lungs are severely underdeveloped, resulting in acute circulatory weakness and respiratory depression. Affected individuals are short in stature and have short extremities and long bones. Skeletal dysplasias usually have numerous complications and do not progress positively with increasing age of the patient.Particularly in newborns, there is respiratory distress due to the overly narrowly developed thorax. Renal insufficiency may develop at an early age. There is also a risk of fibrosis of the pancreas and liver. The too narrow lung is highly susceptible to infections and can cause respiratory paralysis and spontaneous respiratory arrest. There is a risk of cardiovascular failure. As the child grows up, complications increase and diabetes with accompanying visual impairment may occur. The symptom can already be detected in the womb during screening. The degree of manifestation as well as the method of treatment depends on the case. The first therapeutic method considered is normalization of the ventilation parameters, with surgical expansion of the rib thorax. The surgical risk outweighs the child’s chance of survival. Patients with asphyxiating thoracic dysplasia require medical supervision throughout their lives, regarding organ function, as well as physical therapy to keep the impaired musculoskeletal system mobile.
When should one go to the doctor?
Asphyxiating thoracic dysplasia can usually be suspected immediately after birth. The condition is manifested by distinct physical features (including short, horizontally extending ribs with unshortened long bones) that are noticed by the physician in charge, the obstetrician, or the parents themselves. The diagnosis is then confirmed with the help of an X-ray. The subsequent treatment steps depend, among other things, on the severity of the dysplasia. In less severe cases, it is sufficient to treat the infections that occur and to monitor kidney and liver function regularly. Occasionally, novel treatment options such as VEPTR (Vertical expandable prosthetic titanium Ribs) must be resorted to, requiring a longer hospital stay. The responsible physician will suggest the appropriate treatment and arrange appointments for treatment in consultation with the parents of the affected child. Even with successful treatment, the affected person must have regular checkups. If there is a sudden deterioration in health, asphyxiant thoracic dysplasia should be hospitalized immediately.
Treatment and therapy
When treating asphyxiating thoracic dysplasia, the physician must first try to keep the upper airway free of infection. Depending on the additional symptoms that make up the disease in each individual case, he or she may also need to address renal insufficiency and fibrosis of the liver and pancreas. If the patient is suitable for this procedure in an individual case, the VEPTR procedure may be used in some circumstances. This surgical technique aims to permanently expand the thorax. The patient is implanted with a vertically expandable titanium rib prosthesis designed to expand the thorax. Under general anesthesia, the titanium rib is inserted into the patient. The titanium rib has a curved shape and several holes for fixation at the required length. Either the titanium rod is squeezed between two ribs or fixed between a rib and the pelvis. The spine is thus indirectly straightened. The thorax gains volume and the lungs have more space. In some circumstances, several surgeries may be required to stretch the thorax to the desired volume. Patients are selected for this procedure only if the surgery shows promise in their individual case. As long as respiratory infections are present, surgery such as this may not take place anyway. Thus, fighting respiratory infections and stabilizing the patient before surgery is mandatory.
Outlook and prognosis
The prognosis of asphyxiating thoracic dyplasia is very unfavorable. Many affected individuals die within the first few months of life or years after birth. The disease is not considered curable given current scientific and medical options. There is a genetic disposition that cannot be corrected. For legal reasons, research and treatments on human genetics are restricted as well as prohibited. Therefore, there are no sufficient treatment options to change the skeletal system in such a way that a cure or at least alleviation of symptoms would be possible. The internal organs do not have the space they need in the chest to carry out their activities.Functional disorders and, in particular, severe respiratory distress occur. Even with artificial respiration, there is a high risk of death. As the body continues to grow and develop, the space for organs, vessels and surrounding tissue narrows immensely. The process cannot be prevented. If children survive the growth process, their life expectancy is nevertheless not very high. The mortality rate is exorbitantly high in adults with asphyxiating thoracic dyplasia. Significantly decreased life expectancy leads to the poor prognostic outlook. In this disease, the goal is to relieve pain and minimize patient suffering.
Prevention
Because asphyxiating throacic dysplasia corresponds to a gene mutation, the condition cannot be prevented. For parents who have already given birth to a child with asphyxiating throacic dysplasia, the chance of having a second child with the condition is 25 percent.
Follow-up
With this disease, there are usually no or very few aftercare measures and options available to the affected person. First and foremost, a comprehensive diagnosis with subsequent treatment must be carried out to prevent further complications. There can also be no self-healing, so treatment by a doctor must be carried out in any case. The sooner the doctor is consulted for this disease, the better the further course of the disease usually is. A complete cure is not possible, as this is a hereditary disease. If the affected person wishes to have children, hereditary counseling may be useful to prevent the syndrome from being inherited by the descendants. The person affected by this disease is usually dependent on the care and support of his or her own family. Loving and intensive conversations have a positive effect on the course of the disease and can also prevent psychological upsets or depression. Possibly, the life expectancy of the patient is also reduced by this disease.
This is what you can do yourself
Asphyxiating thoracic dyplasia, also known as Jeune syndrome, is a hereditary disease. Affected individuals have no way to treat the disorder causally. Asphyxiating thoracic dyplasia is already apparent in the fetus and can be detected by ultrasound examination. Additional methods of prenatal diagnosis are available if this disorder is suspected. Jeune syndrome is associated with very severe health limitations and is usually fatal. Therefore, a medically indicated termination of pregnancy is possible up to the 24th week of pregnancy. Women who nevertheless decide to carry the pregnancy to term must expect that the child will die during the first two years. For young parents, this represents an enormous psychological burden. They should therefore seek advice and help from other affected persons at an early stage and not be afraid to seek the help of a psychologist. Since the first two years of life are particularly critical for patients suffering from Jeune syndrome, the families of affected children are confronted with constant doctor’s visits, hospital stays and home nursing during this time. How this additional burden can be integrated organizationally into the (professional) everyday life should already be clarified during pregnancy. Self-help groups and health insurance companies provide information about financial and organizational support options.
