This study will identify the role of PACAP (pituitary adenylate cyclase-activating polypeptide) deficiency in patients with nephrotic syndrome. PACAP is a neuropeptide that has a putative role as an inhibitor of megakaryopoiesis and platelet function. Patients with nephrotic syndrome show decreased PACAP plasma levels, due to urinary loss. We hypothesize that in severe nephrotic syndrome, plasma deficiency of PACAP enhances megakaryopoiesis and causes blood platelet activation, which contribute to the increased rate of thromboembolic disease in these patients.

To test our hypothesis, the role of PACAP deficiency on pro-thrombotic state in patients with nephrotic syndrome will be studied using patient blood and urine samples.

Inclusion Criteria:

• New patient with nephrotic syndrome of patient during relapse of nephrotic syndrome
• Under 16 years old
• Treatment for nephrotic syndrome not yet started by first sample collection

Exclusion Criteria:

• None

New patients with nephrotic syndrome of patients during a relapse of nephrotic syndrome.