Early-onset renal amyloidosis associated with psoriasis in a child with cryopyrinopathy: a case report

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BACKGROUND: Cryopyrin-associated periodic syndromes (CAPS) are rare but treatable autoinflammatory disorders, including familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS), and chronic infantile neurologic cutaneous articular syndrome (CINCA), also known as neonatal-onset multisystem inflammatory disease (NOMID). These conditions can lead to severe complications such as AA amyloidosis, potentially resulting in renal failure. To date, the youngest reported case of CAPS-associated amyloidosis was 10 years old, and no cases with overlapping FCAS/MWS/CINCA features have been described. The coexistence of CAPS and psoriasis is extremely rare, with only one prior report. CASE PRESENTATION: We report a 10-year-old boy with features of cryopyrinopathy who developed early-onset AA amyloidosis. Clinical manifestations included bilateral sensorineural hearing loss, severe headaches due to chronic aseptic meningitis, splenomegaly, lymphadenopathy, and progressive renal insufficiency, along with a history of recurrent urticarial-like rashes and arthralgias. Genetic testing revealed a heterozygous pathogenic variant in the NLRP3 gene (NM_001079821.3:c.907G > A; p.Asp303Asn). Variant interpretation, based on ACMG/AMP guidelines, classified this variant as pathogenic (PS1, PS2, PS3, PM1, PM2, PM5, PP1, PP3, PP5). Treatment with the IL-1 receptor antagonist anakinra led to resolution of symptoms, stabilization of renal function, and partial improvement in hearing. During follow-up, the patient developed psoriasis, confirmed by skin biopsy, which was successfully managed with topical therapy. CONCLUSION: To our knowledge, this represents one of the youngest reported cases of AA amyloidosis secondary to CAPS with an overlapping FCAS/MWS/CINCA phenotype. The subsequent co-occurrence of psoriasis highlights the rarity of this case and suggests potential shared pathogenic mechanisms, including dysregulation of inflammatory pathways such as the NLRP3 inflammasome.

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