AnBrasDermatol.2019;94(6):658---663
Anais
Brasileiros
de
Dermatologia
www.anaisdedermatologia.org.brINVESTIGATION
Lack
of
association
between
mutation
in
IL36RN
and
palmoplantar
pustular
psoriasis
in
Chinese
patients
夽,夽夽
Yu
Xiaoling
,
Shu
Dan
,
Jin
Hongzhong
∗DepartmentofDermatology,PekingUnionMedicalCollegeHospital,ChineseAcademyofMedicalSciences,PekingUnionMedical College,Beijing,China
Received9January2018;accepted10January2019 Availableonline26October2019
KEYWORDS Genes; Mutation; Psoriasis
Abstract
Background: Palmoplantarpustulosisisconsideredtobealocalizedpustularpsoriasisconfined tothepalmsandsoles.MutationoftheIL36RNgene,encodinginterleukin-36receptor antago-nist(IL-36Ra),isassociatedwithgeneralizedpustularpsoriasis,butIL36RNmutationsinChinese palmoplantarpustulosispatientshavenotpreviouslybeeninvestigated.
Objective: TheaimofthisstudywastoevaluatethemutationofIL36RNinChinesepatients withpalmoplantarpustulosis.
Methods: Fifty-oneHanChinesepatientswithpalmoplantarpustulosiswererecruited.Allexons andexon-intronboundarysequencesofIL36RNwereamplifiedinpolymerasechainreactions, andSangersequencingoftheampliconswasperformed.
Results: Amongthe51palmoplantarpustulosispatients,fourdifferentsingle-basesubstitutions wereidentifiedinnine patients.The mutationswerec.140A>G/p.Asn47Serinfivepatients, c.258G>A/p.Met86IIeintwopatients,andc.115+6T>Candc.169G>A/p.Val57IIeinonepatient each. All mutationswere heterozygous. Comparisonwith the humangenomedatabase and reportedliteraturesuggested thatthesevariants may notbe pathogenicmutationscausing palmoplantarpustulosis.Furthermore,therewasnodifferenceindiseaseseverity,onsetage, ordiseasedurationbetweenpatientswiththeseheterozygousIL36RNvariantsandthosewithout (p>0.1).
Studylimitation: LackofthefurtherevaluationofIL36Raproteininpalmoplantarpustulosis lesions.
Conclusions: ThefourvariantsofIL36RNidentifieddidnotappeartobeassociatedwiththe specificphenotypesofpalmoplantarpustulosis.
©2019PublishedbyElsevierEspa˜na,S.L.U.onbehalfofSociedadeBrasileiradeDermatologia. ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/ by/4.0/).
夽 Howtocitethisarticle:XiaolingY,DanS,HongzhongJ.LackofassociationbetweenmutationinIL36RNandpalmoplantarpustular
psoriasisinChinesepatients.AnBrasDermatol.2019;94:658---63.
夽夽StudyconductedatthePekingUnionMedicalCollegeHospital,ChineseAcademyofMedicalSciences,PekingUnionMedicalCollege,
Beijing,China.
∗Correspondingauthor.
E-mail:jinhongzhong@263.net(J.Hongzhong).
https://doi.org/10.1016/j.abd.2019.01.008
0365-0596/©2019PublishedbyElsevierEspa˜na,S.L.U.onbehalfofSociedadeBrasileiradeDermatologia.Thisisanopenaccessarticle
Introduction
Palmoplantarpustulosis(PPP)isachronic,relapsing, inflam-matoryskindiseasethatisrestrictedtothepalmsandsoles. PPP appears more frequently in middle-aged adults and women,andusuallydevelopsresistancetotherapy.1Various
factorssuchasmetalallergy,cigarettesmoking,infection, and thyroiddisease areassociated withPPP.2,3 Erythema,
sterile pustules,and scalesarecommon clinical features. Histopathologyshowsparakeratosis,psoriasiformepidermal hyperplasia,spongiosis,andpustulesfilledwithneutrophils. PPPsharesmanyclinicalandhistologicalfeatureswith gen-eralizedpustularpsoriasis(GPP),thusPPPisconsideredto be a localized type of GPP.4 GPP presents as edematous
erythema,withsterilepustulesalloverthebody.
ItisknownthatGPPinpatientswithafamilialhistoryand without psoriasisvulgaris ismainly causedby homozygous or compoundheterozygousmutations oftheIL36RN gene, which encodes an antagonist of IL-36 isoforms, including IL-36␣,IL-36, and IL-36␥.5 IL-36triggers a
proinflamma-toryreactionviathemitogen-activatedproteinkinaseand nuclear factor-B signaling pathways. Mutation of IL36RN results in structural and functional deficiency of IL-36Ra, whichthencannotinhibittheabnormalinflammatory reac-tionmediated byIL-36anditsreceptor.6 The relationship
between IL36RN and PPP has also been studied, but the results are controversial. Research in Japan and Europe has suggested that PPP has no association with IL36RN mutation.7,8 However, another European study indicated
that GPP andPPPunderlie a spectrum ofIL36RN variant-associated pustular psoriasis.9 The present study aimed
toinvestigate theassociation between IL36RN andPPPin Chinese patients, to determine the relationship between IL36RNandPPPandtocontributedataelucidatingtherole thatIL36RNplaysinpustulardiseaseindifferentethnicities.
Methods
Patients
Fifty-oneHanChinesepatientswithPPPintheactivedisease stagewhovisitedtheDepartmentofDermatologyatPeking UnionMedicalCollegeHospitalbetween2014and2016were includedinthisstudy,diagnosedbythesametwo dermato-logicalspecialistsaccordingtotheirclinicalmanifestation, withor withouthistopathology. Pregnant andSAPHO (syn-ovitis,acne,pustulosis,hyperostosis,andosteitis)syndrome patientswereexcluded.Diseaseseverityforeverypatient was assessed using the Palmoplantar Pustular Psoriasis Area and Severity Index (PPPASI), which evaluates the area of lesion involvement (score: 0=none, 0<1≤10%, 10%<2≤30%, 30%<3≤50%, 50%<4≤70%, 70%<5≤90%, 90%<6≤100%)andtheseverityforeachofthethreeclinical skin signs: erythema (E), pustules (P), and desquama-tion(D)(score:0=none,1=slight,2=moderate,3=severe, 4=very severe).10 The final PPPASI was calculated by
(E+P+D) area×0.2 (right palm)+(E+P+D) area×0.2 (left palm)+(E+P+D) area×0.3 (right sole)+(E+P+D) area×0.2(leftsole),whichrangesfrom0to72.Patients’ demographiccharacteristics,PPPonsetage, disease dura-tion, and family history were determined in interviews.
Allpatientsgavewritteninformedconsent.The studywas approvedbytheMedicalEthicsCommitteeofPekingUnion MedicalCollegeHospital;thisworkwasconductedaccording totheDeclarationofHelsinkiprinciples.
Mutationdetection
Bloodsampleswerecollectedfromall51patients.Genomic DNAwasextracted fromperipheralblood leukocytesusing theAxyPrepBloodGenomicDNAMiniprepKit(Axygen Bio-sciences,Tewksbury,MA,UnitedStates).The IL36RNgene sequencewasobtained fromGenBank(NM012275).Seven pairs of primers for the polymerase chain reaction (PCR) amplificationof IL36RN for were designed usingPrimer 5 (http://primer5.ut.ee/) and synthesized by the Majorbio Company(Shanghai, China;Table 1). All five IL36RN cod-ingexons,aswellastheirflankingintrons,wereamplified byPCRusingtheextracted genomicDNAastemplate.The totalvolumeofthereactionswas50L:25Lof2× Easy-TaqPCRSuperMix,4LofDNA,2Lofforwardprimer,2L ofreverseprimer,and17Lofdouble-distilledwater.PCR conditionswereasfollows:initialdenaturationat94◦Cfor 5min; 35cycles ofdenaturation at 94◦C for 30s, anneal-ingat60◦Cfor30s,andelongationat72◦Cfor1min;final elongation at 72◦C for 7min. The amplified PCR products wereverifiedby agarose gelelectrophoresis and observa-tionunderultravioletlight.DNApurificationandsequencing wereperformedbytheMajorbioCompany.Thelikely func-tionofmutantproteinsequenceswasassessedusingtheSIFT and/orPolyPhenpathogenicitypredictiontools.
Statisticalanalysis
Statistical software(SPSS v. 20.0; SPSSInc --- Chicago, IL, UnitedStates)wasusedtoanalyze thedatainthis study. Means and standard deviations were compared between patientswithand without an IL36RN mutation,using Stu-dent’st-testfor independentsamples.When thedatadid notfollowanormaldistribution,theMann---WhitneyU-test
wasused tocalculate statistical significance. A two-class logisticregressionmodelwasappliedtocomparepatients withandwithoutheterozygousIL36RNmutations,adjusted byriskfactors(sex,age,familyhistoryofPPP).The signifi-cancelevelwassetatp<0.05.
Results
Therewere35womenand16menrecruitedin thisstudy. Thepatients’meanagewas48.9±11.9years,andthemean ageofPPPonsetwas45.0±11.9years.Themeanduration of PPPwas 38.7±62.2 months. Nopatients hada family historyof PPP.The mean PPPASIscore ofall patients was 15.1±10.9(Table2).
Four distinct IL36RN mutations were identified among nine of the 51 PPP patients. The four non-synonymous, single nucleotide variants included c.140A>G/p.Asn47Ser in five patients, c.169G>A/p.Val57IIe in one patient, and c.258G>A/p.Met86IIeintwopatients.Thefourth mutation wasc.115+6T>Cinintron3,foundinonepatient.All muta-tionswereheterozygous,andnopatienthadahomozygous
660 XiaolingYetal.
Table1 IL36RNexonprimersequencesandpolymerasechainreaction(PCR)ampliconlengths.
Forwardprimer(5---3) Reverseprimer(5---3) bp
IL-36RN-1 AGTGCTTCTGGCGACTTAGG GGAGAGAGAGGCTGAGTTGG 276
IL-36RN-2 CTGACCCCAGACCCAGAATC AGCTGGACAACGGGTCTATC 261
IL-36RN-3 GTTACTTCTGGCACAGTAGG CACTTTGCTGAGAGGTGTAG 392
IL-36RN-4 TCATGACAGCTGCTGAGAAG AGCTGCCATCAACAGAATCC 386
IL-36RN-5.1 AGATGCTGAGCCTACTGAAG TCTGACATCAGCACCTCCTC 950
IL-36RN-5.2 TAGAGTCAGGGATCTATGGC GTGTCCTCTCCTTTTCATAC 940
IL-36RN-5.3 CAAATTCACATCCTTCTTGG GGGTAAATGAAGGATAGTTG 917
bp,basepair.
or compound heterozygous mutation. The electrophero-gramsofallvariantsareshowninFig.1.
As a result of the functional predictions, p.Asn47Ser and p.Met86IIe were classified as probably damaging by PolyPhen,butastoleratedbySIFT.p.Val57IIewasclassified asbenignandtoleratedbybothPolyPhenandSIFT.
The mean agesof PPPonset with and without IL36RN heterozygosity were 48.7±7.1 and 44.3±12.6 years, respectively. Therewas nosignificant differencebetween thesetwogroups(p=0.378).Themedian(25thpercentile, 75th percentile) disease duration was 14 (6, 36) months for all PPP patients, 12.5 (6, 45) months for patients withheterozygousIL36RN variants,and26 (4,35)months forpatientswithout. Again,nostatisticallysignificant dif-ference was observed (W=165.5, p=0.711). The mean PPPASIscoreswere10.4±9.2forpatientswithheterozygous IL36RNmutationsand16.1±11.1forpatientswithout,with nosignificant differencebetween them (p=0.219). There werestillnodifferencesamongPPPASIscore,disease dura-tion,andonsetagebetweenpatientswithorwithoutIL36RN mutationafteradjustingforsex,age,andfamilyhistoryof PPP(allp>0.1).Theclinicalmanifestationsoftwopatients withorwithoutIL36RNmutationsareshowninFig.2.
Discussion
TheIL36RNgeneislocatedonthelongarmofchromosome 2andconsistsoffiveexons,encodingtheIL-36antagonist, IL-36Ra.11,12 IL-36Rainhibits theIL-36-mediated
inflamma-toryresponsebybindingtotheIL-36receptor.13Pathogenic
mutationsofIL-36RNcausediseasessuchasGPP.6,14,15 PPP
isregardedasalocalizedformofGPP.4
IthasbeenshownthatmanycasesofGPParecausedby mutationsoftheIL36RNgene.16 However,therehavebeen
onlythreestudiesof theIL36RNmutationin PPPtodate, conducted onvarious ethnic groups. Setta-Kaffetzi et al. foundthatsevenPPPpatientsharboredap.Ser113Leu vari-antandfourwerehomozygous,whicharesimilarmutation ratestothosefoundforGPPintheirstudy,indicatingthat theIL36RNalleleswereassociatedwitha phenotypic pro-filethatincludingPPPandGPP.9Incontrast,Mössneretal.
foundfourpatientswithheterozygousIL36RNvariantswho werewithoutpathogenicityamong251PPPpatients,which suggestedthatPPPwasnotassociatedwithloss-of-function IL36RNmutationsinEuropeans.8Takahashietal.foundfour
of88JapanesePPPpatientshadheterozygousIL36RN vari-ants, and similarly concluded that these variants did not
seem to be associated with the phenotype of PPP.7 The
differentresultsinthesereports mayreflectthedifferent ethnicitiesofthestudypopulations.Beforenow,therehave beennostudiesofIL36RNmutationinChinesePPPpatients. Thepresentstudyindicatedthattheremaybenoassociation betweenmutationinIL36RNandpalmoplantarpustulosisin Chinesepatients.
Fifteen distinct mutations have been identified in GPP patients, with p.Ser113Leu, p.Leu27Pro, and c.115+6T>C themostcommonvariantsinEuropean,African,andAsian populations,respectively.17c.115+6T>Caswellasc.227T>C
wereidentifiedasthefounderIL36RNmutationsinstudies ofChinesepatients.5,17
In the present study, four IL36RN variants were identified in Chinese PPP patients. A heterozygous c.140A>G/p.Asn47Ser variant was found in five patients (9.8%). According todata derived fromthe UCSC website of the 1000 Genomes Project, there are 66 among 5008 (1.3%) healthy individuals carrying this variant. Li et al. suggested that among 373 healthy Chinese subjects, 25 (6.7%) carriedp.Asn47Ser, ofwhom24 wereheterozygous and one was homozygous.17 Hayashi et al. reported that
among1120healthyJapanesesubjects,76hada heterozy-gousp.Asn47Servariantandonehadahomozygousvariant (6.9%intotal).18Furthermore,thefrequencyofp.Asn47Ser
carriers among111 Chinesepsoriasisvulgaris patients has been reportedas 9.0%;thus, p.Asn47Ser is likely tobe a polymorphisminPPP.17
ThemostcommonmutantgenotypeinAsianGPPpatients fromChina,Japan, andMalaysiais c.115+6T>C.16,17,19 One
patient(2.0%)inthecurrentstudyandsevenof168(4.2%) healthycontrolsinapreviousstudybythepresentauthors harboredthisheterozygousvariant.20Furthermore,Lietal.
foundthatthefrequencyofc.115+6T>Cwas3.6%inhealthy controlsand1.8%inpsoriasisvulgarispatients,higherthan thatinthePPPgroupofthecurrentstudy.17
The c.169G>A/p.Val57IIe and the c.258G>A/p.Met86IIe were detected in one and two patients respectively, and havenotpreviouslybeenreported.Fromtheavailabledata, heterozygousp.Val57IIeor p.Met86IIevariantsmaynotbe associatedwiththemanifestationofGPPorPPP.p.Val57IIe wasclassifiedasbenignandtoleratedbyPolyPhenandSIFT, and p.Met86IIe was classified as tolerated by SIFT. Thus, thesevariantsmaynotbepathogenicmutationsunderlying PPP.
Overall, there was no difference in severity, mean onsetage,ordiseasedurationbetweenpatientswith het-erozygousIL36RN variantsandthose without.IL36RN may
of association between mutation in IL36RN and palmoplantar pustular psoriasis 661
Table2 Demographiccharacteristicsofpalmoplantarpustulosis(PPP)patients. Numberof
patients
Family history
Meanage Meanonset
ageofPPP Median(25thpercentile, 75thpercentile)disease duration(months) MeanPPPASI Total (male/female)
51(16/35) 0 48.9±11.9(range:26---78) 45.0±11.9(range:24---63) 14(6,36) 15.1±10.9(range:1.2---49.0) Patientswith
heterozygous IL36RNmutations
9(2/7) 0 52.5±8.4(range:40---66) 48.7±7.1(range:40---62) 12.5(6,45) 10.4±9.2(range:1.2---28.9)
Patientswithout heterozygous IL36RNmutations
42(14/28) 0 48.1±12.3(range:26---78) 44.3±12.6(range:24---63) 26(4,35) 16.1±11.1(range:2.1---49.0)
662 XiaolingYetal.
Wildtype
c115+6T>C c.140A>G/p.Asn47Ser c.169G>A/p.Val57lle c.258G>A/p.Met86lle
Heterozygous T/C A/G G/A
G/A
Figure1 SequencechromatogramoftheheterozygousvariantsofIL36RNinpalmoplantarpustulosis.
A
B
Figure2 Clinicalpicture:palmoplantarpustulosisrashonhands:(A)patientwithc.140A>G/p.Asn47Serheterozygousmutation; (B)patientwithnomutationofIL36RN.
havenoassociation withtheclinicalmanifestationofPPP. Another piece of evidence is that the skin lesions of heterozygous IL36RN PPP patients stained positively for IL-36Ra in an immunohistochemical analysis, showing no difference with normal controls.7 Moreover, Onoufriadis
et al. concluded that three GPP patients had homozy-gous (p.Ser113Leu) or compound heterozygous mutations (p.Ser113Leu,p.Arg48Trp),butnomutationwasobservedin anothertwoGPPpatientswithPPPcomplications.14 These
authorsspeculated thatIL36RNisimplicatedinGPPbutis notassociatedwithPPP,whichisconsistentwiththe conclu-sionofthecurrentstudy.Hence,theheterozygousvariants ofIL36RNherein describedmaynotbepathogenicfactors inPPP.Another hypothesisindicated that heterozygousor compoundheterozygousmutationsofIL36RNmaybea pre-disposingfactorforGPPwithpsoriasisvulgarisbecausethree of20GPPpatientswithpsoriasisvulgariscomplicationswere found to carry heterozygous IL36RN variants.16 However,
whetherPPPpatientswithanIL36RNvarianthaveahigher
riskdevelopingGPPisunknown,andneedsfurther investi-gation.
Conclusion
Inconclusion,thefourdifferentIL36RNvariantsdetectedin thisstudyof51Chinesepatientsarenotlikelytobe asso-ciated withthe pathogenesis of PPP. These results are in concordancewithEuropeanand Japanesestudies suggest-ing that IL36RN mutations are not the pathogenic factor underlyingPPP.
Financial
support
National Natural Science Foundation of China 81773331; CapitalsFundsforHealthImprovementandResearch 2016-2-4018.
Author’s
contribution
YuXiaoling:Statisticalanalysis;approvalofthefinalversion of the manuscript;conception and planning of thestudy; elaborationandwritingofthemanuscript;obtaining, ana-lyzingandinterpretingthedata;intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied;criticalreviewoftheliterature.
ShuDan:Approvalofthefinalversionofthemanuscript; conception and planning of the study; effective partic-ipation in research orientation; critical review of the manuscript.
Jin Hongzhong: Approval of the final version of the manuscript;conceptionandplanningofthestudy;effective participation in research orientation; intellectual partici-pation inpropaedeuticand/or therapeutic conductof the casesstudied;criticalreviewofthemanuscript.
Conflicts
of
interest
Nonedeclared.
References
1.Adis¸enE,GürerMA.Therapeuticoptionsforpalmoplantar pus-tulosis.ClinExpDermatol.2010;35:219---22.
2.Giménez-García R, Sánchez-Ramón S, Cuellar-Olmedo LA. Palmoplantar pustulosis: a clinicoepidemiological study. The relationshipbetweentobaccouseandthyroidfunction.JEur AcadDermatolVenereol.2003;17:276---9.
3.SongH,YinW,MaQ.Allergicpalmoplantarpustulosiscausedby cobaltincastdentalcrowns:acasereport.OralSurgOralMed OralPatholOralRadiolEndod.2011;111:e8---10.
4.Misiak-GalazkaM, Wolska H, Rudnicka L. Whatdo we know aboutpalmoplantarpustulosis?JEurAcadDermatolVenereol. 2017;31:38---44.
5.LiX,ChenM,FuX,ZhangQ, WangZ, YuG, etal.Mutation analysisoftheIL36RNgeneinChinesepatientswithgeneralized pustularpsoriasis with/withoutpsoriasis vulgaris.JDermatol Sci.2014;76:132---8.
6.MarrakchiS,GuigueP,RenshawBR,PuelA,PeiXY,FraitagS, etal.Interleukin-36-receptorantagonistdeficiencyand gener-alizedpustularpsoriasis.NEnglJMed.2011;365:620---8.
7.Takahashi T, Fujimoto N, Kabuto M, Nakanishi T, Tanaka T. MutationanalysisofIL36RNgeneinJapanesepatientswith pal-moplantarpustulosis.JDermatol.2017;44:80---3.
8.MössnerR, FrambachY, Wilsmann-TheisD,LöhrS, JacobiA, WeyergrafA,etal.Palmoplantarpustularpsoriasisisassociated
withmissensevariantsinCARD14,butnotwithloss-of-function mutationsinIL36RNinEuropeanpatients.JInvestDermatol. 2015;135:2538---41.
9.Setta-KaffetziN,NavariniAA,PatelVM,PullabhatlaV,PinkAE, ChoonSE,etal.RarepathogenicvariantsinIL36RNunderliea spectrumofpsoriasis-associatedpustularphenotypes.JInvest Dermatol.2013;133:1366---9.
10.Bhushan M, Burden AD, McElhone K, James R, Vanhoutte FP, Griffiths CE. Oral liarozole in the treatment of pal-moplantar pustular psoriasis: a randomized, double-blind, placebo-controlledstudy.BrJDermatol.2001;145:546---53.
11.SmithDE,RenshawBR,KetchemRR,KubinM,GarkaKE,Sims JE.Fournewmembersexpandtheinterleukin-1superfamily.J BiolChem.2000;275:1169---75.
12.TowneJE,GarkaKE,RenshawBR,VircaGD,SimsJE.Interleukin (IL)-1F6,IL-1F8,andIL-1F9signalthroughIL-1Rrp2andIL-1RAcP toactivatethepathwayleadingtoNF-kappaBandMAPKs.JBiol Chem.2004;279:13677---88.
13.TowneJE,RenshawBR,DouangpanyaJ,LipskyBP,ShenM,Gabel CA,etal.Interleukin-36(IL-36)ligandsrequireprocessingfor fullagonist(IL-36␣,IL-36,andIL-36␥)orantagonist(IL-36Ra) activity.JBiolChem.2011;286:42594---602.
14.OnoufriadisA,SimpsonMA,PinkAE,DiMeglioP,SmithCH, Pul-labhatlaV,etal.MutationsinIL36RN/IL1F5areassociatedwith thesevereepisodicinflammatoryskindiseaseknownas gener-alizedpustularpsoriasis.AmJHumGenet.2011;89:432---7.
15.Farooq M, Nakai H, Fujimoto A, Fujikawa H, Matsuyama A, Kariya N, et al. Mutation analysis ofthe IL36RN gene in 14 Japanese patients with generalized pustular psoriasis. Hum Mutat.2013;34:176---83.
16.Sugiura K,Takemoto A, YamaguchiM,TakahashiH, ShodaY, MitsumaT,etal.Themajorityofgeneralizedpustularpsoriasis withoutpsoriasisvulgarisiscausedbydeficiencyof interleukin-36receptorantagonist.JInvestDermatol.2013;133:2514---21.
17.LiM,HanJ,LuZ,LiH,ZhuK,ChengR,etal.Prevalentand raremutationsinIL-36RNgeneinChinesepatientswith general-izedpustularpsoriasisandpsoriasisvulgaris.JInvestDermatol. 2013;133:2637---9.
18.HayashiM,NakayamaT,HirotaT,SaekiH,NobeyamaY,ItoT, et al.NovelIL36RN genemutationrevealedbyanalysisof8 Japanese patientswithgeneralized pustularpsoriasis.J Der-matolSci.2014;76:267---9.
19.Wang TS, ChiuHY, Hong JB, Chan CC, Lin SJ, Tsai TF.
Cor-relation of IL36RN mutation with different clinical features ofpustularpsoriasis inChinese patients.ArchDermatol Res. 2016;308:55---63.
20.ShuD,JinHZ.MutationanalysisofIL36RNinaChineseDaur family with generalized pustular psoriasis. Eur J Dermatol. 2014;24:415---6.
