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IL36RN mutations define a severe autoinflammatory phenotype of generalized pustular psoriasis

Hussain S, Berki DM, Choon SE, Burden AD, Allen MH, Arostegui JI, et al.

J Allergy Clin Immunol, 2015 Apr;135(4):1067-1070.e9.
PMID: 25458002 DOI: 10.1016/j.jaci.2014.09.043
Matched MeSH terms: Psoriasis/genetics*
Fulltext Clinical and genetic differences between pustular psoriasis subtypes

Twelves S, Mostafa A, Dand N, Burri E, Farkas K, Wilson R, et al.

J Allergy Clin Immunol, 2019 03;143(3):1021-1026.
PMID: 30036598 DOI: 10.1016/j.jaci.2018.06.038

BACKGROUND: The term pustular psoriasis indicates a group of severe skin disorders characterized by eruptions of neutrophil-filled pustules. The disease, which often manifests with concurrent psoriasis vulgaris, can have an acute systemic (generalized pustular psoriasis [GPP]) or chronic localized (palmoplantar pustulosis [PPP] and acrodermatitis continua of Hallopeau [ACH]) presentation. Although mutations have been uncovered in IL36RN and AP1S3, the rarity of the disease has hindered the study of genotype-phenotype correlations.
OBJECTIVE: We sought to characterize the clinical and genetic features of pustular psoriasis through the analysis of an extended patient cohort.
METHODS: We ascertained a data set of unprecedented size, including 863 unrelated patients (251 with GPP, 560 with PPP, 28 with ACH, and 24 with multiple diagnoses). We undertook mutation screening in 473 cases.
RESULTS: Psoriasis vulgaris concurrence was lowest in PPP (15.8% vs 54.4% in GPP and 46.2% in ACH, P

Matched MeSH terms: Psoriasis/genetics*
Fulltext Activating CARD14 Mutations Are Associated with Generalized Pustular Psoriasis but Rarely Account for Familial Recurrence in Psoriasis Vulgaris

Berki DM, Liu L, Choon SE, David Burden A, Griffiths CEM, Navarini AA, et al.

J Invest Dermatol, 2015 Dec;135(12):2964-2970.
PMID: 26203641 DOI: 10.1038/jid.2015.288

Caspase recruitment family member 14 (CARD14, also known as CARMA2), is a scaffold protein that mediates NF-κB signal transduction in skin keratinocytes. Gain-of-function CARD14 mutations have been documented in familial forms of psoriasis vulgaris (PV) and pityriasis rubra pilaris (PRP). More recent investigations have also implicated CARD14 in the pathogenesis of pustular psoriasis. Follow-up studies, however, have been limited, so that it is not clear to what extent CARD14 alleles account for the above conditions. Here, we sought to address this question by carrying out a systematic CARD14 analysis in an extended patient cohort (n=416). We observed no disease alleles in subjects with familial PV (n=159), erythrodermic psoriasis (n=23), acral pustular psoriasis (n=100), or sporadic PRP (n=29). Conversely, our analysis of 105 individuals with generalized pustular psoriasis (GPP) identified a low-frequency variant (p.Asp176His) that causes constitutive CARD14 oligomerization and shows a significant association with GPP in Asian populations (P=8.4×10(-5); odds ratio=6.4). These data indicate that the analysis of CARD14 mutations could help stratify pustular psoriasis cohorts but would be mostly uninformative in the context of psoriasis and sporadic PRP.

Matched MeSH terms: Psoriasis/genetics*
Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism: epidemiology, metabolism and the associated diseases

Liew SC, Gupta ED

Eur J Med Genet, 2015 Jan;58(1):1-10.
PMID: 25449138 DOI: 10.1016/j.ejmg.2014.10.004

The Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with various diseases (vascular, cancers, neurology, diabetes, psoriasis, etc) with the epidemiology of the polymorphism of the C677T that varies dependent on the geography and ethnicity. The 5,10-Methylenetetrahydrofolate reductase (MTHFR) locus is mapped on chromosome 1 at the end of the short arm (1p36.6). This enzyme is important for the folate metabolism which is an integral process for cell metabolism in the DNA, RNA and protein methylation. The mutation of the MTHFR gene which causes the C677T polymorphism is located at exon 4 which results in the conversion of valine to alanine at codon 222, a common polymorphism that reduces the activity of this enzyme. The homozygous mutated subjects have higher homocysteine levels while the heterozygous mutated subjects have mildly raised homocysteine levels compared with the normal, non-mutated controls. Hyperhomocysteinemia is an emerging risk factor for various cardiovascular diseases and with the increasing significance of this polymorphism in view of the morbidity and mortality impact on the patients, further prevention strategies and nutritional recommendations with the supplementation of vitamin B12 and folic acid which reduces plasma homocysteine level would be necessary as part of future health education. This literature review therefore focuses on the recent evidence-based reports on the associations of the MTHFR C677T polymorphism and the various diseases globally.

Matched MeSH terms: Psoriasis/genetics
Fulltext AP1S3 mutations are associated with pustular psoriasis and impaired Toll-like receptor 3 trafficking

Setta-Kaffetzi N, Simpson MA, Navarini AA, Patel VM, Lu HC, Allen MH, et al.

Am J Hum Genet, 2014 May 01;94(5):790-7.
PMID: 24791904 DOI: 10.1016/j.ajhg.2014.04.005

Adaptor protein complex 1 (AP-1) is an evolutionary conserved heterotetramer that promotes vesicular trafficking between the trans-Golgi network and the endosomes. The knockout of most murine AP-1 complex subunits is embryonically lethal, so the identification of human disease-associated alleles has the unique potential to deliver insights into gene function. Here, we report two founder mutations (c.11T>G [p.Phe4Cys] and c.97C>T [p.Arg33Trp]) in AP1S3, the gene encoding AP-1 complex subunit σ1C, in 15 unrelated individuals with a severe autoinflammatory skin disorder known as pustular psoriasis. Because the variants are predicted to destabilize the 3D structure of the AP-1 complex, we generated AP1S3-knockdown cell lines to investigate the consequences of AP-1 deficiency in skin keratinocytes. We found that AP1S3 silencing disrupted the endosomal translocation of the innate pattern-recognition receptor TLR-3 (Toll-like receptor 3) and resulted in a marked inhibition of downstream signaling. These findings identify pustular psoriasis as an autoinflammatory phenotype caused by defects in vesicular trafficking and demonstrate a requirement of AP-1 for Toll-like receptor homeostasis.

Matched MeSH terms: Psoriasis/genetics*
Fulltext AP1S3 Mutations Cause Skin Autoinflammation by Disrupting Keratinocyte Autophagy and Up-Regulating IL-36 Production

Mahil SK, Twelves S, Farkas K, Setta-Kaffetzi N, Burden AD, Gach JE, et al.

J Invest Dermatol, 2016 11;136(11):2251-2259.
PMID: 27388993 DOI: 10.1016/j.jid.2016.06.618

Prominent skin involvement is a defining characteristic of autoinflammatory disorders caused by abnormal IL-1 signaling. However, the pathways and cell types that drive cutaneous autoinflammatory features remain poorly understood. We sought to address this issue by investigating the pathogenesis of pustular psoriasis, a model of autoinflammatory disorders with predominant cutaneous manifestations. We specifically characterized the impact of mutations affecting AP1S3, a disease gene previously identified by our group and validated here in a newly ascertained patient resource. We first showed that AP1S3 expression is distinctively elevated in keratinocytes. Because AP1S3 encodes a protein implicated in autophagosome formation, we next investigated the effects of gene silencing on this pathway. We found that AP1S3 knockout disrupts keratinocyte autophagy, causing abnormal accumulation of p62, an adaptor protein mediating NF-κB activation. We showed that as a consequence, AP1S3-deficient cells up-regulate IL-1 signaling and overexpress IL-36α, a cytokine that is emerging as an important mediator of skin inflammation. These abnormal immune profiles were recapitulated by pharmacological inhibition of autophagy and verified in patient keratinocytes, where they were reversed by IL-36 blockade. These findings show that keratinocytes play a key role in skin autoinflammation and identify autophagy modulation of IL-36 signaling as a therapeutic target.

Matched MeSH terms: Psoriasis/genetics*
Fulltext Association of methylentetraydrofolate reductase (MTHFR) 677 C > T gene polymorphism and homocysteine levels in psoriasis vulgaris patients from Malaysia: a case-control study

Liew SC, Das-Gupta E, Wong SF, Lee N, Safdar N, Jamil A

Nutr J, 2012 Jan 05;11:1.
PMID: 22217364 DOI: 10.1186/1475-2891-11-1

BACKGROUND: The methylenetetrahydrofolate reductase (MTHFR) enzyme catalyzes the reduction of 5, 10-methylenetetrahydrofolate to 5-methyltetrahydrofolate and methyl donors. The methyl donors are required for the conversion of homocysteine to methionine. Mutation of MTHFR 677 C > T disrupts its thermostability therefore leads to defective enzyme activities and dysregulation of homocysteine levels.
METHODS: This case-control study (n = 367) was conducted to investigate the correlation of the MTHFR gene polymorphism [NM_005957] and psoriasis vulgaris amongst the Malaysian population. Overnight fasting blood samples were collected from a subgroup of consented psoriasis vulgaris patients and matched controls (n = 84) for the quantification of homocysteine, vitamin B12 and folic acid levels.
RESULTS: There was no significant increase of the MTHFR 677 C > T mutation in patients with psoriasis vulgaris compared with controls (χ(2) = 0.733, p = 0.392). No significant association between homocysteine levels and MTHFR gene polymorphism in cases and controls were observed (F = 0.91, df = 3, 80, p = 0.44). However, homocysteine levels in cases were negatively correlated with vitamin B12 (r = -0.173) and folic acid (r = -0.345) levels. Vitamin B12 and folic acid levels in cases were also negatively correlated (r = -0.164).
CONCLUSIONS: Our results indicate that there was no significant association between the MTHFR gene polymorphism and psoriasis vulgaris in the Malaysian population. There was no significant increase of the plasma homocysteine level in the psoriasis patients compared to the controls.

Matched MeSH terms: Psoriasis/genetics
Fulltext Loss-of-Function Myeloperoxidase Mutations Are Associated with Increased Neutrophil Counts and Pustular Skin Disease

Vergnano M, Mockenhaupt M, Benzian-Olsson N, Paulmann M, Grys K, Mahil SK, et al.

Am J Hum Genet, 2020 09 03;107(3):539-543.
PMID: 32758448 DOI: 10.1016/j.ajhg.2020.06.020

The identification of disease alleles underlying human autoinflammatory diseases can provide important insights into the mechanisms that maintain neutrophil homeostasis. Here, we focused our attention on generalized pustular psoriasis (GPP), a potentially life-threatening disorder presenting with cutaneous and systemic neutrophilia. Following the whole-exome sequencing of 19 unrelated affected individuals, we identified a subject harboring a homozygous splice-site mutation (c.2031-2A>C) in MPO. This encodes myeloperoxidase, an essential component of neutrophil azurophil granules. MPO screening in conditions phenotypically related to GPP uncovered further disease alleles in one subject with acral pustular psoriasis (c.2031-2A>C;c.2031-2A>C) and in two individuals with acute generalized exanthematous pustulosis (c.1705C>T;c.2031-2A>C and c.1552_1565del;c.1552_1565del). A subsequent analysis of UK Biobank data demonstrated that the c.2031-2A>C and c.1705C>T (p.Arg569Trp) disease alleles were also associated with increased neutrophil abundance in the general population (p = 5.1 × 10-6 and p = 3.6 × 10-5, respectively). The same applied to three further deleterious variants that had been genotyped in the cohort, with two alleles (c.995C>T [p.Ala332Val] and c.752T>C [p.Met251Thr]) yielding p values < 10-10. Finally, treatment of healthy neutrophils with an MPO inhibitor (4-Aminobenzoic acid hydrazide) increased cell viability and delayed apoptosis, highlighting a mechanism whereby MPO mutations affect granulocyte numbers. These findings identify MPO as a genetic determinant of pustular skin disease and neutrophil abundance. Given the recent interest in the development of MPO antagonists for the treatment of neurodegenerative disease, our results also suggest that the pro-inflammatory effects of these agents should be closely monitored.

Matched MeSH terms: Psoriasis/genetics*
Emerging landscape in psoriasis management: From topical application to targeting biomolecules

Rapalli VK, Singhvi G, Dubey SK, Gupta G, Chellappan DK, Dua K

Biomed Pharmacother, 2018 Oct;106:707-713.
PMID: 29990862 DOI: 10.1016/j.biopha.2018.06.136

Psoriasis is a chronic autoimmune skin disorder affecting 2-3% of the world population. It has characteristic features such as increased keratinocyte proliferation and production of inflammatory mediators. The treatment involves various strategies including topical, systemic, phototherapy and biologics. Topical therapies are preferred for mild to moderate psoriasis conditions over the systemic therapies which are ideal in severe disease conditions. The systemic therapies include immunosuppressants, biological agents and recently approved phosphodiesterase-4 (PDE4) inhibitors. There are various limitations associated with the existing therapies where the new findings in the pathogenesis of psoriasis are paving a path for newer therapeutics to target at the molecular level. Various small molecules, PDE-4 inhibitors, biologics, and immunomodulator proved efficacious including the new molecules targeting Janus kinases (JAK) inhibitors that are under investigation. Furthermore, the role of genetic and miRNAs in psoriasis is still not completely explored and may further help in improving the treatment efficacy. This review provides an insight into various emerging therapies along with currently approved treatments for psoriasis.

Matched MeSH terms: Psoriasis/genetics