Nephrotic syndrome (NS) is a common glomerulopathy in childhood. Beside idiopathic forms with unclear etiology, genetically determined forms occur.
These monogenic forms essentially differ in treatment and patient's prognosis from the idiopathic ones. They are also clinically and histologically indistinguishable.
The only option of differential diagnosis is molecular genetic testing. The most prominent genes causing genetically determined nephrotic syndrome are NPHS1, NPHS2, WT1 and LAMB2.
Most of the cases of genetically caused NS are resistant to initial steroid therapy. In all patients with steroid-resistant nephrotic syndrome (SRNS) genetic background should be examined and genetically caused NS should be taken to differential diagnosis.
Patients with SRNS should be molecularly genetically tested, at best at the time of renal biopsy.