Kidney Week 2025 Annual Meeting-Young People, Grown-Up Diseases: Approaches to "Adult" Kidney Diseases in Children and Young Adults

Video Transcription

Video Summary

This session, “Young People, Grown-Up Diseases,” focused on kidney diseases that span pediatrics and adulthood, emphasizing how pathologic patterns and new molecular tools refine diagnosis in children and adolescents.<br /><br />Dr. Megan Troxell reviewed monoclonal/“monotypic” immunoglobulin-related renal diseases in youth. True monoclonal gammopathy of renal significance (MGRS) is very rare in children, partly because pediatric B‑cell neoplasms differ from adult plasma cell disorders. However, monotypic deposit diseases do occur, often without detectable serum paraprotein. She highlighted proliferative GN with monoclonal Ig deposits (PGNMID), including pediatric cases with frequent low complement, infection triggers, progression to ESKD, and high post‑transplant recurrence. Emerging data suggest many PGNMID cases may be oligoclonal rather than truly clonal, raising questions about terminology and treatment. She also discussed IgA nephropathy and membranous patterns with light‑chain restriction, including “masked” deposits detectable only with paraffin IF/antigen retrieval, often in young patients with autoimmune features.<br /><br />Dr. Jean Howe summarized advances in membranous nephropathy (MN), contrasting primary (autoimmune podocyte antigens) vs secondary MN (lupus, infections, malignancy, drugs). Pediatric MN is rare and more often secondary, with lower PLA2R positivity than adults. Cohort data show PLA2R remains most common, with higher relative rates of exostosin (often lupus-associated, possibly preceding overt SLE) and semaphorin 3B (noted in very young children). Discussion emphasized biopsy antigen testing vs upfront mass spectrometry (multi‑antigen, faster, avoids tissue exhaustion), and noted some antigens (e.g., semaphorin 3B, NELL1) may recur after transplant.<br /><br />Dr. Sanjeev Sethi presented a pathology-based approach to thrombotic microangiopathy (TMA). Morphology identifies TMA but usually cannot determine cause; clinicians must rapidly exclude Shiga toxin HUS and TTP (ADAMTS13). Atypical HUS remains largely a diagnosis of exclusion, with complement gene variants in ~40–50%. He previewed proteomics efforts to find tissue biomarkers distinguishing complement-mediated aHUS from secondary TMAs.<br /><br />Dr. Joseph Gaut outlined recognizing inherited kidney disease, which accounts for a large fraction of pediatric CKD/ESKD. He emphasized when to suspect genetics (early onset, steroid resistance, cystic disease, family history, extrarenal signs) and showed cases where similar biopsy patterns (e.g., FSGS; GBM “Alport-like” changes) arise from different genes, underscoring the need for genetic confirmation and careful interpretation of variants of uncertain significance.

Asset Subtitle

Moderator(s): Alejandro Best Rocha, Vidhi Dalal

Presentation(s):

Update on Monoclonal Immunoglobulin-Related Diseases in the Pediatric and Adolescent Age Group - Megan Troxell
Advances in Membranous Nephropathy and Target Antigens in Pediatric and Young Adult Patients - Jean Hou
Approach to Thrombotic Microangiopathy in Children and Young Adults - Sanjeev Sethi
Recognizing Early-Onset Inherited Diseases in the Pediatric and Adolescent Population - Joseph Gaut

Meta Tag

Date 11/7/2025

Pathway 1 Pathology

Pathway 2 Pediatric Nephrology

Session ID 507225

Keywords

pediatric kidney disease

adolescent nephrology

monoclonal gammopathy of renal significance (MGRS)

monotypic immunoglobulin deposits

proliferative glomerulonephritis with monoclonal Ig deposits (PGNMID)

oligoclonal vs clonal deposits

low complement glomerulonephritis

post-transplant recurrence

masked deposits paraffin immunofluorescence

membranous nephropathy antigens

PLA2R

exostosin (EXT1/EXT2)

semaphorin 3B

thrombotic microangiopathy (TMA)

genetic kidney disease and inherited CKD