Kozycki et al (2022) Annals Of Rheumatic Diseases
Gain-of-function mutations in ALPK1 cause an NF-κB-mediated autoinflammatory disease: functional assessment, clinical phenotyping and disease course of patients with ROSAH syndrome
Kozycki CT, Kodati S, Huryn L, Wang H, Warner BM, Jani P, Hammoud D, Abu-Asab MS, Jittayasothorn Y, Mattapallil MJ, Tsai WL, Ullah E, Zhou P, Tian X, Soldatos A, Moutsopoulos N, Kao-Hsieh M, Heller T, Cowen EW, Lee CR, Toro C, Kalsi S, Khavandgar Z, Baer A, Beach M, Long Priel D, Nehrebecky M, Rosenzweig S, Romeo T, Deuitch N, Brenchley L, Pelayo E, Zein W, Sen N, Yang AH, Farley G, Sweetser DA, Briere L, Yang J, de Oliveira Poswar F, Schwartz IVD, Silva Alves T, Dusser P, Koné-Paut I, Touitou I, Titah SM, van Hagen PM, van Wijck RTA, van der Spek PJ, Yano H, Benneche A, Apalset EM, Jansson RW, Caspi RR, Kuhns DB, Gadina M, Takada H, Ida H, Nishikomori R, Verrecchia E, Sangiorgi E, Manna R, Brooks BP, Sobrin L, Hufnagel RB, Beck D, Shao F, Ombrello AK, Aksentijevich I, Kastner DL; Undiagnosed Diseases Network
In a large study, spanning identification of patient cohorts, characterization of those patients’ phenotypes, genetic analysis, generation and characterization of animal models, Kozycki et al show that ROSAH syndrome (cause by mutations in the ALPK1 gene) is an autoinflammatory disease with a large range of consequences. They show that treatment with anti-inflammatory drugs is successful. The newly generated animal model only partially replicated the human phenotypes. For example, the mice did not have visual deficits and showed no signs of retinal degeneration.
Objectives: To test the hypothesis that ROSAH (retinal dystrophy, optic nerve oedema, splenomegaly, anhidrosis and headache) syndrome, caused by dominant mutation in ALPK1, is an autoinflammatory disease.
Methods: This cohort study systematically evaluated 27 patients with ROSAH syndrome for inflammatory features and investigated the effect of ALPK1 mutations on immune signalling. Clinical, immunologic and radiographical examinations were performed, and 10 patients were empirically initiated on anticytokine therapy and monitored. Exome sequencing was used to identify a new pathogenic variant. Cytokine profiling, transcriptomics, immunoblotting and knock-in mice were used to assess the impact of ALPK1 mutations on protein function and immune signalling.
Results: The majority of the cohort carried the p.Thr237Met mutation but we also identified a new ROSAH-associated mutation, p.Tyr254Cys.Nearly all patients exhibited at least one feature consistent with inflammation including recurrent fever, headaches with meningeal enhancement and premature basal ganglia/brainstem mineralisation on MRI, deforming arthritis and AA amyloidosis. However, there was significant phenotypic variation, even within families and some adults lacked functional visual deficits. While anti-TNF and anti-IL-1 therapies suppressed systemic inflammation and improved quality of life, anti-IL-6 (tocilizumab) was the only anticytokine therapy that improved intraocular inflammation (two of two patients).Patients' primary samples and in vitro assays with mutated ALPK1 constructs showed immune activation with increased NF-κB signalling, STAT1 phosphorylation and interferon gene expression signature. Knock-in mice with the Alpk1 T237M mutation exhibited subclinical inflammation.Clinical features not conventionally attributed to inflammation were also common in the cohort and included short dental roots, enamel defects and decreased salivary flow.
Conclusion: ROSAH syndrome is an autoinflammatory disease caused by gain-of-function mutations in ALPK1 and some features of disease are amenable to immunomodulatory therapy.
