Objective. Blau syndrome is characterized by noncaseating granulomatous arthritis, dermatitis, and uveitis, and results from gain-of-function NOD2 mutations. This study was undertaken to identify the genetic cause of the disease in a family with 3 members with Blau syndrome.Methods. We studied a family with 3 affected members across 2 consecutive generations. The children's symptoms started early (at 6 and 7 months of age) and included polyarthritis, dermatitis, uveitis, and fever. In contrast, the father's symptoms started later (at 22 years of age) and included noncaseating granulomatous dermatitis and uveitis. We analyzed the NOD2 gene in all patients by both the Sanger method of DNA sequencing and amplicon-based deep sequencing using an Ion Torrent PGM platform.Results. Sanger chromatograms revealed the heterozygous c.1001G>A transition in both children, which resulted in the p.Arg334Gln mutation that causes Blau syndrome. In contrast, the father's chromatograms revealed a small peak of adenine at the c.1001 position, suggesting the presence of a somatic NOD2 mutation. To evaluate this hypothesis, we performed ampliconbased deep sequencing using DNA from different tissues, which confirmed a variable degree (0.9-12.9%) of somatic NOD2 mosaicism. The previous detection of the NOD2 mutation in his daughters strongly suggests the presence of gonosomal (somatic plus gonadal) NOD2 mosaicism in the father. Comparative analyses with Blau syndrome patients carrying the germline p.Arg334Gln NOD2 mutation revealed late onset of the disease, a mild inflammatory phenotype, and an absence of complications in patients with NOD2 mosaicism.Conclusion. This is the first description of gonosomal NOD2 mosaicism as the cause of intrafamilial recurrence of Blau syndrome. Our findings also indicate that Blau syndrome includes more diverse and milder phenotypes than previously described.

Childhood onset systemic lupus erythematosus is a rare disease that is more common amongst Southeast Asian children compared to the West. It is typified by a peripubertal onset and a female preponderance, which increases with advancing age. Organs commonly involved at diagnosis include haematological, renal, and mucocutaneous. Fever, malar rash, and cutaneous vasculitis are common. Lupus nephritis is typically proliferative especially Class IV and contributes to both disease activity and damage. Antinuclear antibody and anti-dsDNA positivity are both prevalent in this region. Disease activity is higher than Western cohorts at onset but responds to therapy reducing to low disease activity by six months. However, organ damage occurs early and continues to accumulate over the time, a consequence of both active disease (neurological and renal systems) and steroid-related complications especially in the eye (cataract and glaucoma) and musculoskeletal systems (avascular necrosis). Infections remain the leading cause of death and mortality in this region is highly variable contributed by the heterogeneity in social economic status, healthcare access, and availability of paediatric rheumatology expertise in the region.

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Background Paediatric systemic lupus erythematosus is a rare autoimmune disease with a wide spectrum of clinical presentation in different populations. We present a cohort of paediatric systemic lupus erythematosus in Malaysia where the disease features and outcomes are still largely unknown. Methods A retrospective review of all paediatric systemic lupus erythematosus patients with at least 6 months follow-up at Selayang Hospital from 2004 to 2016. Epidemiological, clinical and outcome data were collected and analysed. Results A total of 141 paediatric systemic lupus erythematosus patients, 87.9% females, were followed up for a median 6.3 years (interquartile range 3.6–9.0). The median age at diagnosis was 10.8 years (interquartile range 9.0–12.0 years), positive family history of systemic lupus erythematosus was present in 12.1% and the majority (61.7%) were of Malay ethnicity. Common presentations included fever (87.2%), vasculitic rash (72.3%) and lethargy (69.5%). At diagnosis, leukopenia (51.1%), thrombocytopenia (41.8%) and cutaneous lupus (56%) predominate with significant renal involvement (39.7%). Renal (45.4%), liver (26%) and the central nervous system (17%) were important major organs involved during the course of the disease. At diagnosis, almost all (99.3%) patients had high disease activity (mean Systemic Lupus Erythematosus Disease Activity Index score 20.1 ± 9.6). The majority (62.4%) achieved remission or low disease activity after 6 months, maintained over the next 10 years. Damage occurred early (39.1% at 1 year) and increased with time. Ocular damage was the most common side effect (29%) and was predominantly corticosteroid related (93%). Growth retardation was significant (38.2%) with no gonadal failure or secondary malignancies. End-stage renal disease occurred in 3.1% patients whereas 53.1% had sustained renal remission. Overall mortality was 1.4%. Conclusion Despite high disease activity at diagnosis, the majority had good sustained response to treatment with low overall mortality. However, there was progressive accrual of organ damage, highlighting the need for further research and refinements into therapies for paediatric systemic lupus erythematosus.