Congenital bilateral aplasia of the vas deferens is a congenital condition in which the male vas deferens is absent on both sides. The condition is often referred to by the abbreviation CBAVD and occurs either in isolation or in association with mild cystic fibrosis. Congenital bilateral aplasia of the vas deferens is inherited to children in an autosomal recessive manner.
What is congenital bilateral aplasia of the vas deferens?
Congenital bilateral aplasia of the vas deferens is caused by a genetic mutation that occurs on the CFTR gene. In principle, congenital bilateral aplasia of the vas deferens represents a mild variant of cystic fibrosis. However, unlike the classic form of the disease, congenital bilateral aplasia of the vas deferens often lacks only the vas deferens. The spermatozoa usually form the testes in diseased patients in the same way as in healthy individuals. However, due to the complete absence of the vas deferens, the sperm in congenital bilateral aplasia of the vas deferens are hardly able to flow outward. Instead, they only enter the epididymis. In some cases, congenital bilateral aplasia of the vas deferens lacks not only the vas deferens but also the seminal vesicles. In some cases, the urinary tract is affected by malformations. The prevalence of congenital bilateral aplasia of the vas deferens is approximately 0.6 to one percent. If individuals suffer from azoospermia, the cause is found in congenital bilateral aplasia of the vas deferens in approximately three percent of sufferers.
Causes
In most cases, congenital bilateral aplasia of the vas deferens is caused by specific genetic mutations on the CFTR gene. Seventy-five to 90 percent of patients with congenital bilateral aplasia of the vas deferens have such genetic mutations. In addition, other mutations exist that sometimes cause congenital bilateral aplasia of the vas deferens. However, these occur much less frequently. The exact mechanism of pathogenesis of congenital bilateral aplasia of the vas deferens is currently not well understood. For example, it is not yet known why the mutation on the gene called CFTR causes an absence of vas deferens on both sides. Researchers assume that the development of the vas deferens in fetuses is impaired. Another cause of congenital bilateral aplasia of the vas deferens is thought to be blocked ducts, with viscous secretions forming.
Symptoms, complaints, and signs
Congenital bilateral aplasia of the vas deferens is characterized by affected individuals lacking vas deferens on both sides. The vas deferens are absent from birth in congenital bilateral aplasia of the vas deferens. People with genital cystic fibrosis pass the disease on to their children. In addition, offspring have a higher than average incidence of cystic fibrosis. A typical feature of congenital bilateral aplasia of the vas deferens is that semen is hardly transported to the outside, but only to the epididymis, due to the lack of vas deferens.
Diagnosis and course of the disease
The age at which congenital bilateral aplasia of the vas deferens is diagnosed in affected patients varies in individual cases. However, sooner or later, evidence of obstruction of the vas deferens and seminal ducts emerges in most individuals affected with congenital bilateral aplasia of the vas deferens. The general practitioner usually refers the patient to a urologist after a preliminary history and examination. The patient interview focuses primarily on familial predispositions to the disease as well as the presenting symptoms. In this way, the physician narrows down the disease more and more. During the clinical examination, the performance of a spermiogram plays a decisive role. Congenital bilateral aplasia of the vas deferens is primarily recognizable by azoospermia, which indicates obstruction of the seminal ducts. The spermiogram also shows a low pH and a decreased concentration of fructose. The volume of ejaculate is also usually extremely low. In principle, however, many of those suffering from congenital bilateral aplasia of the vas deferens have a normal hormonal status.Congenital bilateral aplasia of the vas deferens is reliably diagnosed by means of a genetic test. This involves detecting mutations on the CFTR gene.
Complications
The absence of both vas deferens in males is a congenital genetic defect. This is considered a mild form of cystic fibrosis. However, genital cystic fibrosis lacks the typical symptoms of cystic fibrosis. The male genetic defect is usually first detected by the family doctor. Often, an unfulfilled desire to have children is the reason to go to the doctor. Since congenital bilateral aplasia of the vas deferens (CBAVD) can be passed on to offspring via the genetic material, further visits to the doctor are necessary for this reason alone. Often, other symptoms are also present that require treatment or correction. In most cases, the urologist is the right person to contact. By means of a spermiogram, the attending physician can determine whether azoospermia is present with minimal sperm volume. However, only a genetic test can reliably determine the presence of congenital bilateral aplasia of the vas deferens. Surgically, the effects of this genetic defect cannot yet be corrected. This would require transplantation of vas deferens. In this respect, a referral to another physician is pointless. An artificial insemination laboratory, on the other hand, can show the possibilities of artificial insemination. However, the transmissibility of the genetic defect must be taken into account. It can cause cystic fibrosis in the offspring. Genetic engineering is not yet ready to intervene here. Later, it will probably be possible to carry out gene repair in the case of such genetic defects.
When should you go to the doctor?
Congenital bilateral aplasia of the vas deferens is a serious genetic disorder that can cause severe psychological problems if left untreated. Affected individuals should seek immediate medical attention or present the affected child to a pediatrician. If the absence of one or both vas deferens is noticed, medical advice must also be sought. Other malformations in the urinary tract should also be examined by a medical professional. If psychological problems arise as a result of infertility, a therapist must be consulted. Therapeutic treatment can help the affected person to come to terms with the condition and the unfulfilled desire to have children. The first point of contact for those affected is the family doctor or a urologist. For possible artificial insemination, a specialized clinic must be visited. Persons suffering from genital cystic fibrosis inherit the disease to their children. Early examination of the child reveals a possible malformation and allows the parents to organize medical appointments and further treatment measures at an early stage.
Treatment and therapy
In principle, it is not possible to treat or cure congenital bilateral aplasia of the vas deferens by surgical intervention. However, affected men have the option of realizing a possible desire for a child by means of artificial insemination. In this case, the sperm is injected intracytoplasmically. In principle, treatment of congenital bilateral aplasia of the vas deferens is therefore only necessary in cases where there is a desire to have children. However, it should be borne in mind that the offspring of patients are particularly predisposed to cystic fibrosis.
Outlook and prognosis
The rare unilateral or the more common congenital bilateral aplasia of the vas deferens may occur as a sequelae of genital cystic fibrosis or without an identifiable cause. Genetic absence or cystic change in both vas deferens results in infertility. Male spermatozoa are formed normally in the testicles. However, without vas deferens, they only reach the epididymis. Nowadays, infertility treatment can improve the prognosis of men affected by congenital bilateral aplasia of the vas deferens. This involves intracytoplasmic sperm injection after a testicular biopsy has been performed. Alternatively, individual sperm can be collected from the ejaculate to determine what severity of aplasia is present. In cases of complete degeneration of the vas deferens, the prognosis is poor for two reasons. First, men with congenital bilateral aplasia of the vas deferens cannot be made fertile by conventional methods.It would be technically possible to remove a completely non-functioning vas deferens and transplant a new one. However, this operation is performed only very rarely. Secondly, the disease is hereditary. It can therefore also be transmitted to the male offspring. In this respect, it is questionable whether offspring should be considered at all when congenital bilateral aplasia of the vas deferens occurs.
Prevention
According to current knowledge, congenital bilateral aplasia of the vas deferens results from genetic mutations, especially those on the CFTR gene. For this reason, the vas deferens is absent even in newborn babies. Options to prevent congenital bilateral aplasia of the vas deferens are therefore not available. However, medical researchers are currently working on ways to treat various genetically caused diseases.
Follow-up
Since this disease is a congenital disease, it usually cannot be completely cured, so the affected person is always dependent on medical examination and treatment in this case, so that there are no further complications and also no further worsening of the symptoms. If the affected person or the parents wish to have children, genetic testing and counseling can provide information to prevent the disease from recurring in the descendants. As a rule, early diagnosis always has a positive effect on the further course of the disease. In most cases, the symptoms can be resolved with the help of surgical intervention. In any case, the affected person should rest after such an operation and not perform any physical or stressful activities. In order to realize a wish for a child, artificial insemination can be used. However, in this case, a genetic examination must be performed before the desire to have a child is pursued. As a rule, no further measures of follow-up care are necessary. In most cases, the disease also does not reduce or limit the life expectancy of the affected person.
What you can do yourself
Congenital bilateral aplasia of the vas deferens does not usually cause any physical symptoms. Therapy as well as any self-help measures focus on accepting the infertility and minimizing effects on the patient’s psyche. This is achieved through therapy sessions, self-help groups and counseling sessions in a specialized clinic. Men who are infertile often also come into conflict with their spouse. Marriage counseling can help mediate the conflicts and show the affected individuals options for fulfilling their desire to have a child. A successful adoption or comparable alternatives help enormously in alleviating the psychological discomfort that affects not only the men, but also their partners. If the desire to have a child remains unfulfilled despite all the measures taken, those affected are usually depressed and frustrated. Any psychological problems should definitely be discussed and worked through with a therapist. Therapeutic treatment should also be sought by those affected who suffer from inferiority complexes and other psychological problems as a result of the malformation. Which measures and steps are useful in detail is best discussed with the psychologist or the family doctor in charge.
