Genetic defects of SLC29A3 result in a wide range of syndromic histiocytosis that encompasses H syndrome. Patients with SLC29A3 variants typically have hyperpigmentation, hypertrichosis, hepatosplenomegaly, sensorineural hearing loss, diabetes mellitus, and hypogonadism. Herein, we identify a novel phenotype in a girl presenting with clinical and laboratory findings similar to systemic juvenile arthritis and hyperferritinemia. Exome sequencing identified a homozygous variant in SLC29A3 (NM_018344.5: c.707C>T [p.T236M]). Our patient did not show the cardinal features of the broad spectrum of SLC29A3-related disorders. She demonstrated remarkable improvement in her clinical and laboratory manifestations after starting interleukin-1 blockade (Anakinra). Recent research suggests that SLC29A3-related disorders are accompanied with autoinflammation and autoimmunity due to an overactive inflammasome pathway, which is most likely induced by mitochondrial and lysosomal dysfunction. Hence, our findings may expand the phenotypic features of the SLC29A3 variant. Patients with the SLC29A3 variant and systemic inflammation may benefit from interleukin-1 blockade as a therapeutic option.

Objective: To report the frequency of selected autoantibodies and their associations with clinical features in Arab children with monogenic lupus. Methods: This study was retrospective single-center study of genetically confirmed monogenic lupus cases at childhood lupus clinic at King Faisal Specialist Hospital and Research Center, from June 1997 to July 2022. We excluded familial lupus without genetic testing and patients with insufficient data. Collected data comprised clinical and laboratory findings, including the autoantibody profile, which included the anti-double-stranded DNA (anti-dsDNA), anti-Smith, anti–Sjögren's-syndrome-related antigen A (anti-SSA), anti–Sjögren's-syndrome-related antigen B (anti-SSB), and antiphospholipid (APL) antibodies. Also, disease activity and accrual disease damage were collected at the last follow-up visit. Results: This study enrolled 27 Arab patients (14 males) with a median age of 11 years (interquartile range 8.0~16 years), with 63% having early-onset disease. The consanguinity rate and family history of lupus were high (74.1% and 55.6%, respectively).The most frequent clinical features were hematological (96.3%), fever (81.5%), mucocutaneous lesions (85.2%), and renal (66.7%).The frequency of the APL antibodies was 59.3%, anti-dsDNA was 55.6%, and anti-Smith and anti-SSA were 48.2% and 44.4%, respectively. Moreover, dsDNA antibodies were significantly associated with musculoskeletal complaints (p<0.05). Likewise, both anti-Smith and anti-SSA antibodies were linked to failure to thrive and recurrent infections in the univariate analysis (p<0.05). Conclusion Our study reveals autoantibody frequencies and their association with clinical and prognostic in a substantial monogenic lupus cohort. Distinct clinical manifestations and prognosis association with certain autoantibodies support the idea that monogenic lupus is a distinctive form of lupus. Larger studies needed to validate these findings.