From Immune System Damage to Podocyte Cell Damage: Prospective Database and Biological Collection of Patients (Children and Adults) With MGLS and HSFP

Inclusion criteria

• First episode of idiopathic nephrotic syndrome in a child aged 12 months to 18 years with a weight > 10 kg and biologically defined as proteinuria > 0.20 g / mmol creatinuria and hypoalbuminemia <25 g / mmol
• First episode of NIS defined in adults as albumin level <30 g / L and a urinary protein/creatinine ratio (UPCR) ≥ 300 mg / mmol systematically associated with the performance of a renal anatomopathological examination and characterized by the absence of identifiable lesions by light microscopy (SNLGM) or the presence of HSF lesions.
• For adults: signed informed consent to participate in the study
• For children: patients will be informed and a written informed consent form will be signed by both parents of the children at inclusion
• Patients affiliated to the French health system

Exclusion criteria

• Patients who have previously received corticosteroids and/or immunosuppressants
• Patients with reduced CH50 and/or low C3 and/or low C4 and/or low C4 (in some cases increased sC5b9 and/or presence of a C3 nephritic Factor; an anti-C3b...)
• SNLGM resulting from a secondary process (lymphoid hematopathies or neoplasia) or occurring following the administration of a treatment known to be associated with an SNLGM (lithium, interferon, non-steroidal anti-inflammatory drugs)
• Non-primary FHH (absence of Nephrotic Syndrome, etiological assessment revealing FHH secondary to an identified cause (genetic or not), no introduction of corticosteroids or immunosuppressants as first-line treatment)
• Positive serological screening test for HIV, hepatitis B or C
• Positive immunological tests for antinuclear and anti-DNA antibodies or anti-PLA2R1 and anti-THSD7A
• Patient under guardianship or curatorship