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

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.