Genetic loci associated with skin pigmentation in African Americans and their effects on vitamin D deficiency

Abstract

A recent genome-wide association study (GWAS) in African descent populations identified novel loci associated with skin pigmentation. However, how genomic variations affect skin pigmentation and how these skin pigmentation gene variants affect serum 25(OH) vitamin D variation has not been explored in African Americans (AAs). In order to further understand genetic factors that affect human skin pigmentation and serum 25(OH)D variation, we performed a GWAS for skin pigmentation with 395 AAs and a replication study with 681 AAs. Then, we tested if the identified variants are associated with serum 25(OH) D concentrations in a subset of AAs (n = 591). Skin pigmentation, Melanin Index (M-Index), was measured using a narrow-band reflectometer. Multiple regression analysis was performed to identify variants associated with M-Index and to assess their role in serum 25(OH)D variation adjusting for population stratification and relevant confounding variables. A variant near the SLC24A5 gene (rs2675345) showed the strongest signal of association with M-Index (P = 4.0 x 10−30 in the pooled dataset). Variants in SLC24A5, SLC45A2 and OCA2 together account for a large proportion of skin pigmentation variance (11%). The effects of these variants on M-Index was modified by sex (P for interaction = 0.009). However, West African Ancestry (WAA) also accounts for a large proportion of M-Index variance (23%). M-Index also varies among AAs with high WAA and high Genetic Score calculated from top variants associated with M-Index, suggesting that other unknown genomic factors related to WAA are likely contributing to skin pigmentation variation. M-Index was not associated with serum 25(OH)D concentrations, but the Genetic Score was significantly associated with vitamin D deficiency (serum 25(OH)D levels less than 12 ng/mL) (OR, 1.30; 95% CI, 1.04–1.64). The findings support the hypothesis suggesting that skin pigmentation evolved responding to increased demand for subcutaneous vitamin D synthesis in high latitude environments.

Examination of the Missense Mutation (rs74653330, Ala481Thr) of the Oculocutaneous Albinism 2 Gene to the Facial Skin Characteristics

“…This is the same as the results of previous studies [18,21,22] and is the same as the result of the decreased amount of sebum secretion as aging progresses based on the amount of sebum measured in the forehead, cheek, and chin areas, which are commonly measured. In particular, in the case of women, there is a report that the amount of sebum secretion decreases rapidly before and after menopause [23,24], and it can be con rmed that in our results, it is reduced by almost half which a group of after the 50year is than the group under the age of 35 year. Overall, as a result of analyzing the aging effect on the skin beauty phenotype in this result, the aging of Korean women appears to be more wrinkles, more moisture, less melanin, and less oily skin than the skin phenotype results of other races or countries [18,[23][24][25].…”

Incident Of Vitamin D Deficiency In Derna City\libya

“…This study concurs with the uncover to sun [41]. Yet not concur with the relationship with nourishment lack in Vitamin D. Openness to the sun and a decent eating routine are frequently sufficiently not to forestall a Vitamin D deficiency.…”

“…Yet not concur with the relationship with nourishment lack in Vitamin D. Openness to the sun and a decent eating routine are frequently sufficiently not to forestall a Vitamin D deficiency. Also not concur with [41]. The most noteworthy pace of Vitamin D inadequacy was found in spring(40%).…”

Vitamin D intake and cognitive decline in Blacks and Whites: The role of diet and supplements

“…However, we reported these significant associations among Blacks and not Whites. Compared to Whites, Blacks produce less vitamin D from the skin in response to usual levels of sun exposure, 37,38 suggesting that dietary vitamin D becomes critical among them. Alternatively, Whites with a lower intake of vitamin D may have adequate serum levels of 25-hydroxy vitamin D due to skin synthesis, and additional vitamin D from the diet or supplements may not add any additional benefit to their cognitive functioning.…”