Congenital absence of the vas deferens (CAVD) is a condition in which the vasa deferentia

reproductive The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are a ...

organ Organ may refer to: Biology * Organ (biology), a part of an organism Musical instruments * Organ (music), a family of keyboard musical instruments characterized by sustained tone ** Electronic organ, an electronic keyboard instrument ** Hammond ...

s fail to form properly prior to birth. It may either be unilateral (CUAVD) or bilateral (CBAVD).

Signs and symptoms

The vas deferens connect the sperm-producing

testicles A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosteron ...

to the

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...

. Therefore, those who are missing both vas deferens are typically able to create sperm but are unable to transport them appropriately. Their

semen Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Sem ...

does not contain sperm, a condition known as

azoospermia Azoospermia is the medical condition of a man whose semen contains no sperm. It is associated with male infertility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen ...

. Unilateral absence may not show any abnormalities in semen analysis. Vas deferens are less commonly palpated during routine a physical examination, hence the absence may go unnoticed. Also, injury to Vas deferens common in surgery. Vas deferens may be absent on one or both sides, and in whole or in part. When only a part of Vas deferens is absent, it may fail to establish communication with the epididymis. In one of the largest such studies, a study of 23,013 individuals seeking for vasectomy, 159 were suspected to be having UAVD. Among 159 men identified as potentially having CUAVD, 47 had only one testicle, 26 had bilateral vasa, and four were misdiagnosed (post-vasectomy semen analysis showing motile sperm after unilateral vasectomy) leaving 82 men deemed cases of CUAVD (0.36% of total sample). 82 men were further classified as confirmed (n=48, 0.21%) and possible (n=34, 0.15%; 22 without and 12 with scrotal anomalies) congenital UAVD. The misdiagnosis ratio of CUAVD was low when scrotal content was otherwise normal (1:48), but higher if anomalies were present (3:12).

Causes

There are two main populations of CAVD; the larger group is associated with

cystic fibrosis Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. Ot ...

and occurs because of a mutation in the CFTR gene, while the smaller group (estimated between 10 and 40%) is associated with unilateral

renal agenesis Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop. Unilateral and bilateral renal agenesis in humans, mice and zebra fish has been linked to mutations in the gene GREB1L. It has als ...

(URA). The mutational spectrum of CFTR in the first group differs from that observed in classic cystic fibrosis, with milder missense or splice variants present on at least one chromosome. The genetic basis of the second group is not well understood. In the subset of males with both CBAVD and URA, the CFTR mutation has been shown to occur at a rate only slightly higher than the overall population. It has been suggested that another gene may be responsible for this condition. Mutation of the CFTR gene is found to result in obstructive azoospermia in postpubertal males with cystic fibrosis. Strikingly, CAVD is one of the most consistent features of cystic fibrosis as it affects 98-99% of individuals in this CF patient population. In contrast, acute or persistent respiratory symptoms present in only 51% of total CF patients.

Diagnosis

Scrotal ultrasonography Scrotal (or transscrotal) ultrasound is a medical ultrasound examination of the scrotum. It is used in the evaluation of testicular pain, and can help identify solid masses. Indications Although the development of new imaging modalities such as c ...

and

transrectal ultrasonography Transrectal ultrasonography, or TRUS in short, is a method of creating an image of organs in the pelvis, most commonly used to perform an ultrasound-guided needle biopsy evaluation of the prostate gland in men with elevated prostate-specific anti ...

(TRUS) are useful in detecting uni- or bilateral CAVD, which may be associated with visible abnormalities or

agenesis In medicine, agenesis () refers to the failure of an organ to develop during embryonic growth and development due to the absence of primordial tissue. Many forms of agenesis are referred to by individual names, depending on the organ affected: *A ...

of the epididymis, seminal vesicles or kidneys.

Treatment

Individuals with CAVD can reproduce with the assistance of modern technology with a combination of

testicular sperm extraction Testicular sperm extraction (TESE) is a surgical procedure in which a small portion of tissue is removed from the testicle and any viable sperm cells from that tissue are extracted for use in further procedures, most commonly intracytoplasmic sperm ...

and intracytoplasmic sperm injection (ICSI). However, as the risk of either cystic fibrosis or renal agenesis is likely to be higher in the children,

genetic counseling Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease; t ...

is generally recommended.

References

External links

* * {{Channelopathy Congenital disorders of male genital organs Cystic fibrosis