Genetic epidemiology and heritability of vitiligo in the Qassim region of Saudi Arabia.
OBJECTIVE
Assessment of consanguinity and inheritance patterns in relation to clinical subtypes of vitiligo among Saudi cases in the Qassim region based on a vitiligo case series during 2008 taken from the Qassim University-affiliated referral center.


METHODS
This study included 111 randomly selected Saudi probands affected by vitiligo and their families. They included 61 males and 50 females. Their mean age of onset was 19.13 +/- 11.97 years. Data were collected using a questionnaire administered by professional dermatologists emphasizing the clinical features as well as consanguinity and segregation pattern. Genetic analyses for inbreeding coefficient, mode of inheritance, and heritability were statistically analyzed.


RESULTS
Out of 111 probands, the frequencies of focal, vulgaris, universal, and acrofacial subtypes were 32.4%, 31.5%, 9.9%, and 26.1%, respectively. Parental consanguinity was positive in 32.4% of cases and first-cousin consanguinity in 22.5% with an inbreeding coefficient of 0.015. The family history was positive in 56.8% of cases. The mean age of onset was 19.13 +/- 11.97 years with a median of 17 years. The median age of onset was lower for consanguineous cases and cases with a positive family history. Inheritance patterns coincided more with the multifactorial model, especially for the vulgaris subtype followed by the acrofacial subtype, and coincided least with the focal subtype. Heritability or the genetic contribution to the disease showed a high weighted mean of 0.54.


CONCLUSIONS
Genetic factors contribute to the evolution of vitiligo among Saudi families. Discouraging consanguineous marriage is a potential prevention measure. Genetic factors contribute to the evolution of vitiligo among tribal areas of the Saudi community probably through the high consanguinity rate. In that respect, family counseling can be attempted that would discourage consanguinity and combat probable interactive environmental and health factors.
Alzolibani
Abdullateef
A
Department of Dermatology, College of Medicine, Qassim University, Saudi Arabia, PO Box 30109, Buraidah 51477, Qassim, Saudi Arabia. azolibani@yahoo.com
D000328:Adult; D003241:Consanguinity; D005260:Female; D005799:Genes, Dominant; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D012529:Saudi Arabia / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D014820:Vitiligo / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D055815:Young Adult