|
|
|
Bilateral Renal Agenesis or Severe Renal Hypoplasia (absence of both kidneys or
undeveloped kidneys)
|
|
What is this condition and what is its significance?
|
Bilateral renal agenesis occurs in 1 out of every 4000 births, and it results in
fetal death because of inadequate lung development. The lack of formation of urine
causes a marked reduction in the amount of amniotic fluid, and this leads to underdevelopment
of the lungs. The urinary bladder cannot be demonstrated on ultrasound examination. Severe renal hypoplasia
causes a similar clinical syndrome, even though the undeveloped kidney is visible
in some cases.
Renal agenesis frequently occurs in combination with other defects such as heart
(14%) and skeletal (40%). Defects in the nervous system and digestive system have
also been reported. In 10% of the cases of multicystic/dysplastic kidney, the other
kidney is absent.
Studies have shown that there is a high frequency of chromosome abnormalities in
cases of kidney disorders of this type. When renal agenesis occurs as an isolated
finding, the risk of a chromosome abnormality is 5%, as opposed to 38% when there
are other defects as well.
In some cases of renal agenesis, one of the parents lacks a kidney. Often the parent
does not even know because it has no clinical significance.
|
What should be done when this condition is diagnosed?
|
The family should first be referred to a nephrologist for counseling about the implications.
They should then be referred for
genetic counseling to determine whether or not it is part of a genetic syndrome.
Termination of pregnancy is recommended, and this should be accompanied by careful
planning of what tests should be performed in order to confirm the presence of the
condition in the fetus. Chromosome
analysis and specific examination for additional defects should also be carried
out on the fetus.
The parents should be referred for an ultrasound scan of the kidneys. The diagnosis
of an abnormality in one of the parents increases the risk of recurrence to 50%
in future pregnancies, whereas the absence of this condition in the parents considerably
reduces the recurrence risk.
|
|
|