Bilateral Renal Agenesis is the absence of both kidneys at birth. It is a genetic disorder characterized by a failure of the kidneys to develop in a fetus. This absence of kidneys causes a deficiency of amniotic fluid (Oligohydramnios) in a pregnant woman. Normally, the amniotic fluid acts as a cushion for the developing fetus. When there is an insufficient amount of this fluid, compression of the fetus may occur resulting in further malformations of the baby.
This disorder is more common in infants born of a parent who has a kidney malformation, particularly the absence of one kidney (unilateral renal agenesis). Studies have proven that unilateral renal agenesis and bilateral renal agenesis are genetically related.
Bilateral renal agenesis is characterized by the absence of kidneys and of urine in a baby. The face usually consists of wide-set eyes; a “parrot beak” nose; a receding chin, and large low set ears deficient in cartilage. Other symptoms may include excess and dehydrated skin, a prominent fold at the corner of each eye, the facial expression of an older infant, and deformities of the hands and feet.
Premature labor, breech delivery and a disproportionately low birthweight are often associated with bilateral renal agenesis. The baby may also have multiple malformations including in females the absence of a uterus and upper vagina, or in males an absence of seminal vesicles and spermatic duct. Gastro-intestinal malformations such as the absence of a rectum, esophagus and duodenum may also occur. Symptoms may further include the presence of only a single umbilical artery, and major deformities of the lower part of the body and the lower limbs.
Bilateral renal agenesis is an autosomal dominant genetic disorder. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed “dominating” the other normal gene and resulting in the appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child.
Bilateral renal agenesis tends to occur when at least one parent has a kidney malformation or the absence of a kidney (unilateral kidney agenesis).
Bilateral renal agenesis is found in male infants more frequently than females. It tends to occur in the children of parents having kidney abnormalities. It is a very rare disorder.
Research into the cause of renal agenesis is ongoing, with the hope of identifying the gene that causes this birth defect.
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