Monogenic interferon-mediated diseases: novel phenotype and genotype characteristics from a Saudi population.

OBJECTIVES: IFN-mediated diseases are mendelian innate immunodysregulatory disorders that present early in life with fevers, sterile organ inflammation, and a high type-I IFN-response gene signature in peripheral blood cells. To date, monumental discoveries of novel genetic variants with various phenotypic features have been recognised. We aimed to describe the genotype and phenotype findings in Saudi children diagnosed with autoinflammatory interferonopathy and to report novel findings. METHODS: This is a descriptive retrospective cohort study of children with genetically confirmed type I interferonopathies. Medical records were reviewed for demographic, family history, clinical and laboratory data. All patients underwent genetic testing. RESULTS: A total of 20 patients (11 females) were included in the study. Sixteen patients (80%) presented within the first 2 years. The median age of disease onset was 0.87 years (IQR: 0.5-2) and the median age of diagnosis was 4.5 years (IQR: 2-7.5). The rates of consanguinity and family history of affected members were high (88% and 47%, respectively). Among the cohort of patients, whole exome sequencing was conducted for 15 patients. Three patients underwent targeted gene tests, and 2 patients had a leukoencephalopathy genetic panel. Eight patients were diagnosed with Aicardi-Goutières syndrome, attributed to variants in the RNASEH2A, RNASEH2C, and IFIH1 genes. Additionally, 2 patients were identified with STING-associated vasculopathy with onset in infancy linked to the TMEM173 variant. One patient exhibited chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature due to PSMB8, and another patient had DNase II. Moreover, 8 patients presented with rare interferonopathy conditions, including three with ISG15, 3 with ZNFX1, 1 with the SOCS1 variant, and 1 the STAT1 variant. Of 12 variants, six (50%) found to have novel genetic variants. The most frequent features were fever (75%), neurology (70%), mucocutaneous (60%), gastrointestinal (50%), and pulmonary (50%). Hypogammaglobinaemia and recurrent infections were seen in (45%) and (20%), respectively. Fifteen patients (75%) had elevated inflammatory markers. The majority of patients received intensive treatment, including corticosteroids, JAK inhibitors, IVIG, and various immunosuppressive agents. Despite these interventions, a partial response to treatment was observed, and cumulative disease damage primarily manifested as growth failure and developmental delay. CONCLUSIONS: Our findings support the previous reports; early-onset fever, neurology, and respiratory features should raise the suspicion of interferonopathies. However, there is eminent evidence of phenotypic variability. Our data also expanded the spectrum of clinical findings in relation to novel genetic variants.

The SLC29A3 variant, neutrophilic dermatosis, and hyperferritinemia imitate systemic juvenile idiopathic arthritis in a Saudi child: a case report.

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.

New insights on genetic variants and phenotypic features of childhood large-vessel vasculopathy: a systematic review and single-centre series.

OBJECTIVES: To describe the phenotypic, genetic, and outcome characteristics of large-vessel vasculopathy (LVV) in childhood associated with genetic variants. Additionally, a systematic literature review was conducted to delineate the differences between LVV with and without genetic variants. METHODS: The medical records of all children with LVV seen between January 2000 and September 2022 at our institution were retrospectively reviewed for demographic, clinical and genetic data, and outcomes at the last follow-up visit. In addition, we systematically reviewed the literature for the clinical features and known variants of previously reported cases. RESULTS: Eleven patients with childhood LVV were identified; five (three males) of them had proven genetic variants (two DOCK8variants, one FOXP3, one DiGeorge syndrome, and one ZNF469 variant), while six patients had sporadic childhood LVV. Remarkably, patients with genetic variants were younger and had early-onset disease. However, the diagnosis of LVV was delayed compared to those without genetic variants. All patients with genetic variants were treated with corticosteroids, and three patients required sequential immunosuppressive drugs. Four patients underwent surgical intervention, and one received a haematopoietic stem-cell transplant (HSCT). Three patients achieved clinical remission, and two died. Furthermore, data from 20 previously published cases was extracted from the literature. All patients had inherited disorders. Of those, 14 patients had a genetically proven diagnosis. Most of them are treated with corticosteroids and immunosuppressive drugs, with partial responses. Two patients underwent HSCT. There were four deaths. CONCLUSIONS: This study demonstrates that a variety of inherited disorders may contribute to childhood LVV. Strong genetic evidence and the preponderance of autosomal-recessive inheritance may allow us to propose that monogenic LVV is a distinct entity.

Familial Clustering of Juvenile Psoriatic Arthritis Associated with a Hemizygous FOXP3 Mutation.

PURPOSE OF REVIEW: We describe the clinical and genetic findings in four patients from a single family who presented with refractory psoriatic arthritis and were hemizygous in the forkhead box protein 3 (FOXP3) gene (c.1222G>A). RECENT FINDINGS: We report four siblings with hemizygous mutation in the FOXP3 gene (c.1222G>A) who presented with type 1 diabetes mellitus and psoriatic arthritis poorly responsive to treatment. Our findings expand the phenotype spectrum of FOXP3 mutations. Immune dysregulation, polyendocrinopathy, and enteropathy, X-linked (IPEX) syndrome is a rare disorder caused by mutations in FOXP3 gene, which lead to early onset of constellation of autoimmune manifestations. This report highlights the influence of immune dysregulation in juvenile arthritis.