Nephrotic syndrome, idiopathic, steroid-resistant

Nephrotic Syndrome, Idiopathic, Steroid-Resistant

Nephrotic syndrome, idiopathic, steroid-resistant (SRNS) is a rare kidney disorder characterized by the body's inability to respond to steroid treatment, which is typically used to manage nephrotic syndrome. This condition leads to significant proteinuria, hypoalbuminemia, hyperlipidemia, and edema.

Pathophysiology

The pathophysiology of SRNS involves damage to the glomerulus, the filtering unit of the kidney. This damage is often due to genetic mutations affecting the podocytes, which are specialized cells that play a crucial role in the kidney's filtration barrier.

Genetic Factors

SRNS is often associated with genetic mutations. Some of the genes implicated include:

• NPHS1 - encoding nephrin, a key component of the slit diaphragm.
• NPHS2 - encoding podocin, another critical protein in the slit diaphragm.
• WT1 - associated with Wilms' tumor and other syndromic forms of nephrotic syndrome.

Clinical Presentation

Patients with SRNS typically present with:

• Proteinuria - excessive protein in the urine.
• Edema - swelling, particularly in the legs and around the eyes.
• Hypoalbuminemia - low levels of albumin in the blood.
• Hyperlipidemia - elevated levels of lipids in the blood.

Diagnosis

Diagnosis of SRNS involves:

• Urinalysis - to detect proteinuria.
• Blood tests - to assess levels of albumin and lipids.
• Genetic testing - to identify mutations associated with SRNS.
• Kidney biopsy - to examine the kidney tissue for characteristic changes.

Treatment

Treatment options for SRNS are limited due to the resistance to steroids. They may include:

• Calcineurin inhibitors - such as cyclosporine or tacrolimus.
• ACE inhibitors or ARBs - to reduce proteinuria and protect kidney function.
• Immunosuppressive agents - like cyclophosphamide or mycophenolate mofetil.
• Supportive care - including diuretics for edema and statins for hyperlipidemia.

Prognosis

The prognosis for patients with SRNS varies. Many patients progress to chronic kidney disease and may eventually require dialysis or kidney transplantation. Early genetic diagnosis and targeted therapy can improve outcomes.

Research and Future Directions

Ongoing research is focused on understanding the genetic basis of SRNS and developing targeted therapies. Advances in genomics and personalized medicine hold promise for better management of this condition.

See Also

• Nephrotic syndrome
• Chronic kidney disease
• Dialysis

NIH genetic and rare disease info

• NIH info on Nephrotic syndrome, idiopathic, steroid-resistant

Nephrotic syndrome, idiopathic, steroid-resistant is a rare disease.