Understanding Renal Dysplasia and Renal Agenesis
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What is renal dysplasia and agenesis?
Renal dysplasia and renal agenesis are conditions that affect how a baby’s kidneys develop before birth.
- Renal dysplasia: kidneys develop abnormally and may not function properly
- Renal agenesis: one or both kidneys fail to develop
During pregnancy, a baby’s kidneys produce urine, which becomes a major part of the fluid that surrounds the fetus (amniotic fluid). This fluid is essential for:
- Lung development
- Fetal movement and growth
Low amniotic fluid (oligohydramnios) or no amniotic fluid (anhydramnios) can signal impaired kidney function and may impact outcomes.
(Pic: illustration of a child with oligohydramnios due to renal agenesis)
What causes renal dysplasia or agenesis?
In many cases, the exact cause is unknown. Potential causes include:
Genetic Factors
- Chromosomal abnormalities
- Single-gene conditions (e.g., HNF1B-related disorders)
- Syndromic associations (e.g., Fraser syndrome)
Developmental Abnormalities
- Disruption in early kidney formation
- Abnormal interaction between ureteric bud and metanephric tissue
Environmental / Maternal Factors
- Maternal diabetes
- Certain medications (e.g., ACE inhibitors, ARBs)
- Reduced blood flow to developing kidneys
(Pic: illustration of a child with poorly developed kidneys)
Fetal Center: the first step in care
Multidisciplinary Evaluation: meet with MFM specialist, pediatric nephrologist, pediatric urologist, neonatologist, and other experts who may care for your baby
Comprehensive Imaging: detailed ultrasounds and other tests when indicated to assess your baby's condition and help plan treatment
Coordinated Delivery Planning: our team works to ensure your baby receives immediate specialized care at birth if needed
How are kidney problems evaluated in the fetus?
Fetal kidney problems are usually found on screening prenatal ultrasound. Referral to our center leads to additional testing to fully characterize what problems are present and any underlying causes.
Ultrasound Findings
- Absent kidneys (agenesis)
- Small, echogenic, or cystic kidneys (dysgenesis)
- Low or absent amniotic fluid
- Non-visualized or small bladder
Additional Testing
- Serial ultrasounds to monitor growth and fluid
- Fetal MRI (in select cases for anatomy clarification)
- Genetic counseling and testing
- Chromosomal microarray
- Targeted gene panels when indicated
Key Prognostic Factors
- Unilateral vs. bilateral involvement
- Amniotic fluid volume
- Presence of associated anomalies
(Pic: fetal ultrasound with arrow demonstrating a dysplastic kidney)
Is there prenatal treatment of renal agenesis?
Treatment depends on severity and goals of care:
Expectant Management
- Ongoing monitoring with ultrasound
- Multidisciplinary counseling (maternal-fetal medicine, nephrology, urology and neonatology)
Counseling and Planning
- Discussion of prognosis and potential outcomes
- Review of all options, including continuation of pregnancy with neonatal care planning or palliative approaches
Interventions (in very select cases)
- Amnioinfusion (investigational in many centers): where fluid is added to the amniotic cavity
- May temporarily improve amniotic fluid levels
- Intended to support lung development in severe renal disease
- May NOT be offered to patients with bilateral renal agenesis (BRA) due to poor outcomes
(Pic: Illustration of child undergoing amnioinfusion for oligohydramnios)
Expected outcomes
Outcomes depend on the severity of the kidney disease.
Unilateral Renal Agenesis or Mild Dysplasia
- Often good prognosis
- Many children live normal lives with one functioning kidney
- Long-term monitoring for kidney health is recommended
Bilateral Renal Agenesis (BRA)
- Typically not survivable due to severe lung underdevelopment
- Will need treatment for kidney replacement (dialysis)
Bilateral Severe Dysgenesis
- Variable but often serious
- May result in kidney failure at or shortly after birth
(Pic: Child treated with kidney disease in the NICU)
Where should a child with renal dysplasia or genesis be delivered?
Babies with severe renal dysplasia or agenesis should be delivered at our center with a neonatal intensive care unit (NICU) that specializes in the care of these infants and where a nephrologist (kidney doctor) and other pediatric specialists can immediately evaluate your child. The neonatologist is a specially trained pediatrician that will manage your baby’s medications, feeding, and daily needs while in the NICU.
Some children with mild renal dysplasia can be delivered closer to home and then follow-up with pediatric nephrology as an outpatient. Consultation at the fetal center can help determine the best place for delivery.
How is a child with a kidney abnormality initially stabilized?
Many of these children will require placement of a tube into the airway (endotracheal tube) and placement on a ventilator to assist with breathing. Additionally a tube placed through the mouth (oral gastric or OG) into the stomach to remove contents to prevent stomach and bowel dilation. Eventually, this tube will be replaced with a feeding tube through the nose (NG tube) to help feed the child.
Your baby will receive fluids and antibiotics through a special IV called a PICC line, initially through the umbilical cord, then placed in one of the limbs. Because the child will not be initially allowed to eat, they will also receive nutrition through the PICC line called TPN, or total parenteral nutrition. TPN contains protein, fat, sugar, vitamins, and minerals and will meet all your baby’s nutritional needs.
Depending on the severity of kidney disease, some will require placement of a special catheter in a large vein, usually in the neck, to allow for hemodialysis to begin (HD catheter). This helps the team manage the child's electrolytes and to eliminate waste the body usually excretes in the urine.
(Pic: illustration of a child with renal agenesis treated in the NICU)
How is renal dysplasia or agenesis treated after initial stabilization?
Definitive Treatment depends on the underlying cause.
The NICU, Nephrology, and Urology teams will work together to come up with the best plan to treat the baby based on kidney function and other studies.
If long-term dialysis is needed, a special dialysis catheter can be placed in the abdomen, to allow for peritoneal dialysis to occur at home after the child is discharged from the hospital (PD catheter).
(Pic: child with renal agenesis that requires placement of a PD catheter)
Long-term kidney Care
Children with kidney dysplasia or agenesis often require ongoing care to monitor:
- Kidney function
- Bladder function
- Growth and development
Some children may develop chronic kidney disease and require specialized care by Nephrology and Urology.
- Children that require kidney transplant typically won't qualify until 18 - 24 months of age to accommodate an adult sized kidney.
Follow the link below to meet the Kidney Care team at Primary Children's Hospital
