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Study of the association of tumor necrosis factor promoter gene polymorphism (TNF-308) and susceptibility to vitiligo

Thesis

Last updated: 06 Feb 2023

Subjects

-

Tags

Dermatology

Advisors

Saleh, Nadya F., El-Mungi, Naglaa N., Basyouni, Dalya A., Khourshid, Mirvat M.

Authors

Abdel-Magid, Khadiga Sayed

Accessioned

2017-07-12 06:42:21

Available

2017-07-12 06:42:21

type

M.D. Thesis

Abstract

Background: Vitiligo is a disorder of pigmentation characterized by the presence of depigmented skin macules due to chronic and progressive loss of melanocytes from the cutaneous epidermis. A number of polymorphisms within the gene coding for TNF-α has been described. Exchange of guanine by adenine at position –308 of the TNF-α promoter region is associated with higher serum levels of soluble TNF-α. Moreover, it has been associated with susceptibility to wide variety of diseases including vitiligo.Aim of work: The aim of the present study is to investigate the association between an inherited genetic polymorphism at TNF-α –308 (G→A) and vitiligo.Patients and methods: The study will be conducted on 100 middle aged (18-49 years) female patients with non-segmental vitiligo; and 110 age and sex matched controls, from each A 3ml blood sample was taken for detection of TNF-α -308 gene polymorphism by Restricted Fragment Length Polymorphism (RFLP) PCR.Results: A higher frequency of the TNF-α -308 A allele polymorphism (homozygous or heterozygous) in vitiligo patients than controls (P=.000) was found. No statistically significant difference was found between cases with normal genotype and those with mutant genotype as regard the age (P=.052), extent (P=.169), age of onset (P=.106), duration of illness (P=.435), type of vitiligo (P=.258), family history of vitiligo (P=.136), associations with other autoimmune conditions (P=.570), presence of amelanotic hair (P=.206), and response to treatment (P=.571). The odds ratio between individuals with normal genotype and those with the mutant genotype was 5.040 with the 95% confidence interval 2.771-9.168, which means that an individual with mutant gene is 5 times more susceptible to vitiligo than an individual with normal genotype. A statistically significant difference was noticed between vitiligo patients with heterozygous gene mutation and those with homozygous gene regarding the response to therapy, with the presence of poor/mild responses to therapy among patients with heterozygous genotype, while good response to therapy was seen in those with homozygous genotype (P=.001), while no statistically significant difference was noticed between the two patient groups regarding the age (P=.521), age of onset (P=.308), extent of the disease (P=.627), duration of illness(P=.778), associations with other autoimmune conditions (P=.307), family history of vitiligo (P=.744) and presence of amelanotic hair (P=.531). The odds ratio between cases of vitiligo with homozygous genotype and those with heterozygous genotype was 10.400 with the 95% confidence interval 4.101-26.377. This means that an individual with homozygous genotype is 10 times more susceptible to vitiligo than an individual with heterozygous genotype. Conclusion: A higher frequency of the TNF-α 308 gene polymorphism (homozygous or heterozygous) is observed in vitiligo patients than normal controls. An individual with TNF-α 308 gene polymorphism is five times more susceptible to vitiligo than normal individual. An individual with homozygous genotype is ten times more susceptible to vitiligo than individual with heterozygous genotype.

Issued

1 Jan 2011

DOI

http://dx.doi.org/10.21473/iknito-space/37829

Details

Type

Thesis

Created At

28 Jan 2023