Papillorenal Syndrome- All You Need to Know

Introduction

Papillorenal syndrome is an autosomal dominant condition that affects the optic nerve (a nerve that carries information from the brain to the eye) and the kidneys. A genetic condition that can be passed down from parents to their children is called an autosomal dominant character. People with this condition have small kidneys which are underdeveloped and often lead to end-stage renal disease. In this condition, the kidneys are not able to filter the waste products from the body. Studies show that about ten percent of children with small and underdeveloped kidneys have papillorenal syndrome.

What Is Papillorenal Syndrome?

Papillorenal syndrome is also called renal coloboma syndrome. It mainly affects the kidneys and the eyes. Other complications can include auditory abnormalities, musculoskeletal anomalies, and central nervous system defects. The symptoms are usually bilateral, though they can be unilateral in some cases. The underdeveloped kidneys can progress to end-stage renal disease and eye impairment can lead to retinal detachment and eventually blindness.

What Are the Synonyms of Papillorenal Syndrome?

• Renal Coloboma Syndrome.

• PAX-2-related disorder.

• Optic nerve coloboma with renal disease.

• Coloboma ureteral renal syndrome.

• Optic coloboma.

• Vesicoureteral reflux.

• Renal anomalies syndrome.

• Renal hypodysplasia.

What Are the Causes of Papillorenal Syndrome?

Studies show that about half of the population with papillorenal syndrome has undergone a genetic mutation in chromosome number ten. This gene is important for making a protein transcription factor for changing genetic expression in the early development of the kidneys, the eyes, ears, the brain, and the spinal cord during the uterine stages. A transcription factor helps in converting DNA (deoxyribonucleic acid) to RNA (ribonucleic acid). These transcription factors are also important in many processes after birth.

What Are the Symptoms Of Papillorenal Syndrome?

Abnormalities in renal functions are one of the first noted symptoms. In very rare cases renal dysfunctions do not show any symptoms and go unnoticed. Renal hypoplasia shows symptoms as early as in utero of oligohydramnios (reduced amniotic fluid) and Potter sequence. Potter sequence is the result of reduced amniotic fluid and reduced kidney function of the fetus. It is present as chronic renal failure along with nephrolithiasis (kidney stones or renal calculi), pyelonephritis (inflammation of the kidneys due to an infection), and fluid retention in adults.

How Is Papillorenal Syndrome Diagnosed?

There is still no standard mode of diagnosis for the condition. Patients who show signs of retinal coloboma are tested for renal anomalies. Conversely, patients with renal anomalies are also tested for optic nerve dysfunctions. Patients with optical anomalies are evaluated for blood pressure, electrolyte balance, creatinine levels, and urine analysis:

1. Physical Examination: Optic disc dysplasia is the most consistent finding observed in these patients. The optic disc is the round spot in the retina where the axons of the nerve come together. The optic disc is seen to be enlarged with the blood vessels coming from the periphery. It is observed that the retinal vessels are more in number and more tortuous in such patients. Studies show that about thirty to eighty percent of these patients might have near-sightedness or other impairments in vision.

2. Imaging: CT scans and renal ultrasounds of these patients show relatively smaller or underdeveloped kidneys.

3. Genetic Tests: Molecular genetic tests can help to identify the genetic mutations that cause the conditions.

How Is Papillorenal Syndrome Managed?

Currently, there are no medications or genetic modifications known to cure the condition. The condition is managed by preventing and reducing the complications associated. Monitoring the risk factors associated with hypertension and vesicoureteral reflux (a condition where urine flows back from the bladder to the ureter or the kidneys) is necessary to prevent or delay chronic kidney failure. End-stage renal disease can be managed by dialysis. An organ transplant can be considered at this stage. Protective lenses can be used to prevent retinal detachment and blindness. Low vision aids can be used following the significant loss of vision to help accessibility and be functional. Monitoring should be done for other systemic symptoms as well.

What Are the Differential Diagnoses of Papillorenal Syndrome?

The differential diagnoses of papillorenal syndrome include those conditions where coloboma (an eye condition where a part of the tissue forming the eye is missing) or renal anomalies have been observed. They include:

• CHARGE Syndrome: CHARGE stands for coloboma, heart malformations, atresia choanae, retardation of growth and development, genital anomalies, and hearing abnormalities. People with papillorenal syndrome will not have cognitive difficulties (difficulty in thinking or learning) or craniofacial abnormalities( birth defects of the face or head.

• Oligomeganephronia: It is a type of renal hypoplasia where the histologic findings are similar. The symptoms may differ in both conditions.

• Branchio-oto-renal Syndrome (BOR Syndrome): It is a genetic condition where the tissues of the neck, ear, and kidneys are not developed properly. It is also an autosomal dominant disorder.

• COACH or Joubert Syndrome: It stands for cerebellar defect, oligophrenia, ataxia, coloboma, and Hepatic fibrosis. It is a rare autosomal recessive condition that mainly affects the brain and the liver. It differs from patients with papillorenal syndrome in that the latter will not have a developmental disability, cerebellar hypoplasia, cerebellar dysfunction, and hepatic dysfunction. Cerebellar hypoplasia is a neurological condition where the cerebellum, which is a part of the brain, is not developed properly. Cerebellar dysfunction causes difficulty with gait and balance problems, often restricting movements.

• Cat Eye Syndrome: It is a genetic anomaly that can cause problems in many parts of the body. It is a rare disorder where an extra segment of a chromosome is seen. There are abnormalities associated with the eyes, ears, anal region, heart, and kidney. The iris colobomas are not seen in patients with papillorenal syndrome.

• ARO Syndrome: Acro-renal-ocular syndrome is a rare congenital anomaly characterized by optic nerve coloboma, renal malformations, prominent upper limb abnormalities, and urinary tract abnormalities.

Conclusion

Papillorenal syndrome is a rare genetic condition that affects the development of the kidney and the eye. The prognosis of the disease depends upon the coexisting conditions of the patient as well as the systemic involvement of the condition. In general, the prognosis is worse for people who develop complications early. Detection of the disease at an early stage will help in improved diagnosis and better management. Further research is required to understand more about the condition, especially the long-term outcome.