Genotype‒Phenotype Correlation of TRPV3-Related Olmsted Syndrome

We have previously shown that gain-of-function variations in transient receptor potential vanilloid-3 (TRPV3) underlay Olmsted syndrome, a rare hyperkeratotic skin channelopathy. In this study, we attempt to establish genotype‒phenotype correlation which has been unclear owing the rarity and heterogeneity of condition. identified five unreported TRPV3 (R416Q, R416W, L655P, W692S, L694P) three recurrent (G568D, G568V, L673F) nine unrelated patients. Seven variants were expressed human embryonic kidney 293 cells, channel behavior was characterized electrophysiologically, with results compared clinical severity. These variant channels, either homomeric or heteromeric form, exhibited differentially elevated basal open probability, increased voltage sensitivity, cytotoxicity. Functional changes particularly pronounced corresponding severer syndrome (e.g., L673F W692S) but not mild R416Q). Interestingly, extent functional rescue by wild-type vitro also consistent severity variants. findings, combination all reported cases, indicate preliminary correlation, is, S4‒S5 linker domain significantly enhance function, causing severe phenotype, whereas other appear exert milder effects on function disease phenotype. (OS) is genodermatosis principally palmoplantar keratoderma (PPK) periorificial hyperkeratosis (Mevorah et al., 2005Mevorah B. Goldberg I. Sprecher E. Bergman R. Metzker A. Luria al.Olmsted syndrome: mutilating keratotic plaques.J Am Acad Dermatol. 2005; 53: S266-S272Abstract Full Text PDF PubMed Scopus (41) Google Scholar). Keratoderma usually progressive mutilation, leading disability hands feet ranging from flexion deformities autoamputation digits. Periorificial can be found around mouth, anus, perineum, nostrils, ear meatus, predilection for mouth corners. Other frequently features include alopecia, perifollicular keratosis, nail dystrophy, leukokeratosis Scholar; Tang 2012Tang L. Zhang Ding H. Wang X. new case complicated easily broken hair treated oral retinoid.J 2012; 39: 816-817Crossref (7) Some patients experience intolerant itching and/or pain sensation areas. Histologically, OS psoriasiform epidermal hyperplasia inflammatory infiltration upper dermis, instance, massive mast cell superficial dermis (Lin 2012Lin Z. Chen Q. Lee M. Cao J. Ma D. al.Exome sequencing reveals mutations as cause syndrome.Am J Hum Genet. 90: 558-564Abstract (212) Mevorah demonstrated TRPV3, encoding (TRP) protein mainly keratinocytes, studies revealed channels constitutively open, significant death variant-expressing mammalian cells through possible calcium overload (Xiao 2008Xiao Tian Zhu M.X. The mutation associated hairless phenotype rodents active.Cell Calcium. 2008; 43: 334-343Crossref (68) Correspondingly, higher percentage apoptotic keratinocytes detected lesions OS, suggesting might due apoptosis when expressing hyperactive channels. Apart two genes later OS: MBTPS2 X-linked recessive (Haghighi 2013Haghighi Scott C.A. Poon D.S. Yaghoobi Saleh-Gohari N. Plagnol V. al.A missense gene underlies form syndrome.J Invest 2013; 133: 571-573Abstract (36) 2014Wang H.J. Z.L. Lin Z.M. Dai L.L. Yang Y. Recurrent splice-site underlying IFAP syndrome-like Chinese patient.Clin Exp 2014; 158-161Crossref (20) Scholar) PERP autosomal-dominant (Dai 2020Dai S. Sun alopecia universalis caused heterozygous PERP.Br 2020; 182: 242-244PubMed Duchatelet 2019Duchatelet Boyden L.M. Ishida-Yamamoto Zhou Guibbal Hu al.Mutations dominant keratoderma.J 2019; 139: 380-390Abstract (14) nonselective cation tetrameric architecture four subunits symmetrically arranging an aqueous pore (Zubcevic 2018Zubcevic Herzik Jr., M.A. Wu Borschel W.F. Hirschi Song A.S. al.Conformational ensemble ion channel.Nat Commun. 2018; 9: 4773Crossref (60) Each subunit six transmembrane domains (S1–6), N-terminus C-terminus located intracellularly. consists ankyrin repeat domain, pre-S1 helix, contains TRP proposed interact between S4 S5 (Singh 2018Singh A.K. McGoldrick Sobolevsky A.I. Structure gating mechanism TRPV3.Nat Struct Mol Biol. 25: 805-813Crossref (85) Zubcevic When activated agonists such 2-aminoethoxydiphenyl borate (2-APB), S6 opens becomes permeable cations selectivity divalent ions magnesium ions. Although TRPV3-related very only 38 cases date, identification increasing number across different recent expansion phenotypic spectrum (Wilson 2015Wilson N.J. Cole C. Milstone Kiszewski A.E. Hansen C.D. O'Toole E.A. al.Expanding 2015; 135: 2879-2883Abstract (19) made it investigate correlation. aim whether there genotypic aspects To end, enrolled varying severity, whom are identified. A variants, (HEK)293 their properties extensively characterized, except patient 7, who Italian Caucasian. Patients 2, 3, 9 mild, focal, nonmutilating PPK, others had much more severe, diffuse, PPK. 1, 3 positive family history (Supplementary Figure S1), rest sporadic. No abnormalities hematological, biochemical, immunological tests noted. Detailed listed Table representative phenotypes 1a‒c.Table 1Characteristics VariationsVariationPatientSexOnset Age (PPK, y)Age Visit (y)PPKPeriorificial KeratodermaHair AbnormalitiesNucleotide (Amino Acid)ExonFamily HistoryLesional ItchLesional Pain1M125+++; asymmetric; diffuse PPK left sole hand; right side‒‒c.1246C>T (p.R416W)10+AD‒‒2M540++; focal hand foot; side normal‒‒c.1246C>T (p.R416W)10+AD++++/△3M828++; symmetric; nonmutilating+; corners coccygeal region+; lusterless coarsec.1247G>A (p.R416Q)10+AD++++4M15 d7++++; mutilating+++; ear, perianal area+; partial white hairc.1703G>T (p.G568V)13‒++++++++5M516++++; planta; palms+++; region‒c.1703G>A (p.G568D)13‒‒‒6F135+++; nonmutilating; constriction digital bands‒‒c.1964T>C (p.L655P)15‒‒‒7M28++; nonmutilating‒+++; thin, coarse, unmanageable hypotrichosisc.2017C>T (p.L673F)15‒++++++/△8M1.57+++; bone absorption terminal digits++; area+++; moderate hypotrichosis, broken; eyebrows eyelashes affectedc.2075G>C (p.W692S)15++++9M17++; both feet; digits hands+; mouth‒c.2081T>C (p.L694P)15‒‒‒Abbreviations: AD, autosomal dominant; F, female; M, male; syndrome; vanilloid-3; keratoderma.The following symbols used: ‒, absent/normal; +, present; ++, mild; +++, moderate; ++++, severe; △, erythermalgia. Open table tab Abbreviations: keratoderma. Sanger targeting these L673F), state S2). All segregated perfectly those absent healthy parents 200 individuals. From total 21 hitherto known selected seven studies; mutated R416Q/W N-terminus, W521S S2‒3 linker, causes G573A/V S4‒5 W692S domain. order determine consequence variations, along (WT) transiently HEK293 currents recorded using patch-clamp electrophysiology inside-out configuration. WT generated weak voltage-dependent outward showed robust response 300 μM 2-APB (Figure 2a c ). R416Q, larger currents, although they retained strong rectification characteristic seen (Figures Supplementary S3a b). induced activation. By contrast, G573A, G573V, L673F, lost characteristic, resulting nearly linear current‒voltage relationship b S3a) This fully opened Moreover, large negligible further 2c d S3b), high spontaneous activities. confirm observation further, performed single-channel recordings test probability (Po) without extrinsic activation, namely Po. conductance clearly Po activation 2e f). R416Q variant, level comparable 0.8. Given markedly leaves less room reach full opening, may explain responses majority heterozygotes allele plays role over coexpressed allele, implies coassemble vivo likely overall hyperactive. assembly, cotransfected cDNAs at 1:1 ratio, mimicked genetic background variations. Overall, formed similar alone 3). Heteromeric G573A little identical counterparts. suggested coassembly insufficient effect 3a–d S3). displayed reduced stronger lower than f 3e presence resulted complete hyperactivity As Scholar), measured each W692S). Consistent our previous results, rate 4a cytotoxicity partially alleviated coexpression indicating could rescued b) accordance electrophysiological However, rescuing coexpressing WT. Our data obtained constructs indicated For example, 3c). Nevertheless, measurement confounded variation-induced cytotoxicity, downregulation expression (Li 2014Li Hasan thermal sensitivity TRPV1 determined PKCβII.J Neurosci. 34: 8246-8258Crossref (31) Loukin 2011Loukin Su Kung Increased activity key determinant skeletal dysplasia TRPV4 mutations.PLoS One. 2011; 6e19533Crossref (42) clarify concatemers cDNA covalently linked including head-to-tail fashion 5a). Transfection did dramatic (data shown), condition, sufficient cytotoxic Thus, should no affected then tested concatemers. First, concatemer low yielded observed upon monomeric 5b d). containing outwardly rectifying observed. opening even negative potentials, remarkable inactivation potentials c). applied concatemers, which, overall, elicit 5d e). inward (which scenario where one, two, present), findings confirmed supporting Variations MBTPS2, implicated pathogenesis additional reported, erythromelalgia (Danso-Abeam 2013Danso-Abeam Dooley Staats K.A. Van Eyck Brussel T. exploration phenotype.Orphanet Rare Dis. 8: 79Crossref 2014aDuchatelet de Veer Fraitag Nitschké P. Zarhrate vanilloid mutations.Br 171: 675-678Crossref (21) Scholar, 2014bDuchatelet Pruvost Bole-Feysot erythromelalgia.JAMA 150: 303-306Crossref (32) Because noted (patients 2 7) (Cao 2016Cao Li Jiang al.Semidominant inheritance 2016; 136: 1722-1725Abstract (11) Ni 2016Ni Yan Cheng Liang Deng novel atypical familial syndrome.Sci Rep. 6: 21815Crossref (23) Wilson one suspect represent important feature rather just coincidental Clinical presentation eight varies greatly, involvement modifier environmental factors. yet well-established keratoderma, abnormality still used primarily classification erythromelalgia, degree lesional itch informative subsequent classification. triggered warmth, reasonable speculate thermosensitive temperature-gating threshold, hypersensitivity innocuous stimuli (Luo Hu, 2014Luo Thermally channels.Curr Top Membr. 74: 325-364Crossref (29) Moore 2018Moore Gupta Jordt S.E. Liedtke W.B. Regulation channels.Neurosci Bull. 120-142Crossref (111) Another explanation interaction sodium 1.7, whose underlie inherited (Yang 2004Yang Xu SCN9A, alpha subunit, primary erythermalgia.J Med 2004; 41: 171-174Crossref (573) Future investigation will address speculations. It remains challenging make diagnosis features, thereby necessitating importance variation testing general, typical (severe) least lack above S4). reviewed date residues G573 W692 tend seem associate S1). classify into basis hair, sensory hypotrichosis) gain insights responsible individual forms representing structure domains. extensive characterization physiologically relevant (i.e., channels) region variation, properties, (patient 3) functionally study. causes, rectification, 2-APB, slightly Po, vitro. R416 residue shared element assembly TRPV1-4 2-APB‒mediated Singh heat sensing (Yao 2011Yao Liu Qin F. Modular sensors temperature-gated channels.Proc Natl Sci USA. 108: 11109-11114Crossref (143) folding, trafficking (Garcia-Elias 2015Garcia-Elias Berna-Erro Rubio-Moscardo Pardo-Pastor Mrkonjić Sepúlveda R.V. al.Interaction pre-S1, determines TRPV channels.Structure. 23: 1404-1413Abstract Liao 2013Liao Julius electron cryo-microscopy.Nature. 504: 107-112Crossref (1050) Furthermore, according recently three-dimensional model (PDB 6MHO), relatively far away S6b–c), its expected impact indirectly, change 201