Genetics of multiplex familial vitiligo as cases and controls: a preliminary report
Keywords:Familial vitiligo, Multiplex vitiligo families, Whole exome sequencing
Background: Studies on etiology of generalized vitiligo have established that it is a genetically determined, autoimmune, auto inflammatory diathesis. Polymorphism in myriad genes is associated with vitiligo and newer ones are being identified with advancement in research methods. This study enabled inheritance pattern recognition in multiplex familial cases of vitiligo and subject members to whole exome sequencing (WES) to find out the etiological gene defect in a particular family.
Methods: 7 multiplex families with at least two cases and two healthy counterparts, spread across generations were enrolled. Demographic data, clinical history and familial data were collected for pedigree analysis and blood samples were collected for extraction of genomic DNA.
Results: Multiple possible modes of Mendelian inheritance could be contemplated to cause disease expression in probands. Autosomal recessive pattern was observed to be the most likely amongst various possible modes, followed closely by autosomal dominant, with X-linked recessive, and X- linked dominant occurring less frequently. WES for one of the multiplex families is desirable and planned at an apex institute of genetic studies which will reveal the etiologic gene defect on conclusion of analysis.
Conclusions: In this study we have used to our advantage the familial occurrence of the disease to seek for genes which occurred with a greater frequency in affected members of a family than their healthy counterparts, assuming that the same mutated gene should be universally present in all affected members across generations in the same family, enabling a better understanding of genetic predisposition in familial vitiligo.
Sehgal VN, Srivastava G. Vitiligo: Compendium of clinico-epidemiological features. Indian J Dermatol Venereol Leprol. 2007;73:149-56.
Ezzedine K, Lim HW, Suzuki T, Katayama I, Hamzavi I, Lan CC, et al. Revised classification/nomenclature of vitiligo and related issues: The Vitiligo Global Issues Consensus Conference. Pigment Cell Melanoma Res 2012;25:1-3.
Boisy RE, Spritz RA. Frontiers and controversies in the pathobiology of vitiligo: Separating the wheat from chaff. Exp Dermatol. 2009;18:583-5.
Spritz RA. The genetics of generalized vitiligo. Curr Dir Autoimmun. 2008;10:244–57.
Shen C, Gao J, Sheng Y, Dou J, Zhou F, Zheng X, et al. Genetic Susceptibility to Vitiligo: GWAS Approaches for Identifying Vitiligo Susceptibility Genes and Loci. Front Genet. 2016;7:3.
Das SK, Majumder PP, Chakrabotry R, Majumdar TK, Haldar B, and Rao DC. Studies on vitiligo I. Epidemiological profile in Calcutta, India. Genet Epidemiol. 1985;2:71–8.
Majumder PP, Nordlund JJ, Nath SK. Pattern of familial aggregation of vitiligo. Arch Dermatol. 1993;129:994-8.
Kim SM, Chung HS, Hann SK. The genetics of vitiligo in Korean patients. Int J Dermatol. 1998;37:908-10.
Alkhateeb A, Stetler GL, Old W, Talbert J, Uhlhorn C, Taylor M, et al. Mapping of an autoimmunity susceptibility locus (AIS1) to chromosome 1p31. 3–p32. 2. Hum Mol Genet. 2002;11:661-7.
Majumder PP, Das SK, Li CC. A genetical model for vitiligo. Am J Hum Genet. 1988;43:119-25.
Das SK, Majumder PP, Majumdar TK, Haldar B, Rao DC. Studies on vitiligo. II. Familial aggregation and genetics. Genet Epidemiol. 1985;2:255-62.