Photoaging is premature aging of the skin caused by ultraviolet (UV) radiation from the sun and artificial sources. It is associated with the marker rs322458 and the genes STXBP5L and FBXO40. This marker has two alleles, A and G. The G allele is the risk allele associated with more severe photoaging. The A : A genotype on the other hand is associated with less severe photoaging.
A : A
Less severe photoaging
A : G
More severe photoaging
G : G
More severe photoaging
Photoaging manifests mainly as sagging and wrinkling of the skin. Pigmented spots such as freckles and lentigines may appear. Photoaging usually occurs on the most exposed areas of the body – face, neck and hands.
Photoaging is caused by extrinsic or environmental factors. The main factor is sun exposure. UV radiation from the sun has several damaging effects on the skin. It causes mutations in the DNA and forms reactive oxygen species (ROS). Furthermore it causes the degradation of collagen and other important structural features of the skin.
The main method of protecting your skin from photoaging is sunscreen. Sunscreens work by blocking or absorbing UV radiation. A proper sunscreen should protect against both UVB and UVA radiation. Antioxidants protect the skin from damaging effects of free radicals. They decrease wrinkles and increase collagen, which is an important structural protein in the skin.
Topical solutions should be used, as oral intake does not result in increased levels in the skin. Retinoids are synthetic derivatives of vitamin A. Vitamin A and retinoids increase collagen production and inhibit some negative effects of UV radiation. Retinoids can be found in many skin creams and lotions.
People with genotypes G : G and G : A should take extra caution. Exposure to sun and to artificial sources of UV radiation (e.g. tanning beds) should be limited. Meticulous application of sunscreen is necessary. It should be noted that clouds do absorb some but not all UV radiation. Use of topical antioxidants and retinoids can be considered.
Even though people with the genotype A : A do experience less severe photoaging, UV radiation still has a damaging effect on their skin as well. Use of sunscreen and limiting excess exposure to sun and to artificial sources of UV radiation (e.g. tanning beds) is still necessary.
*Canadian Dermatology Association Photoaging. (https://dermatology.ca/public-patients/skin/photoaging/) Retrieved 06.07.18 Le Clerc, S., Taing, L., Ezzedine, K., Latreille, J., Delaneau, O., Labib, T., Coulonges, C., Bernard, A., Melak, S., Carpentier, W., et al. (2013).
*A Genome-Wide Association Study in Caucasian Women Points Out a Putative Role of the STXBP5L Gene in Facial Photoaging. Journal of Investigative Dermatology 133, 929–935.
*Rafieepour, A., Ghamari, F., Mohammadbeigi, A., and Asghari, M. (2015). Seasonal Variation in Exposure Level of Types A and B Ultraviolet Radiation: An Environmental Skin Carcinogen. Annals of Medical and Health Sciences Research 5, 129–133.
*Rosi Helfrich, Y., Sachs, D., and J Voorhees, J. (2008). Overview of skin aging and photoaging.
The information provided in this article is based on published SNP (single nucleotide polymorphism) data and is for educational purposes only. Most published studies about genetic variants in the DNA explain only a small part of the heritability of a trait or disease risk, and often do not take into account how different variants may interact with each other. In addition, many published studies do not account for medical history or environmental, dietary, microbial, or lifestyle factors, which may alter true risk for any trait or disease.
The relevance of each article may vary based on ethnicity. Nothing in the genetic article should be used for medical self-diagnosis or self-treatment. The information provided should not be considered complete, nor should it be relied on to suggest diagnosis or treatment of a particular individual. You should always get the advice of your doctor or other appropriate health care professional if you have any questions about diagnosis, treatment, prevention, mitigation, or cure of any medical condition, phenotype, condition, impairment, or the status of your health.
An allele is a variant form of a gene that is located at a specific position, or genetic locus, on a specific chromosome. Humans have two alleles at each genetic locus, with one allele inherited from each parent.
A chromosome is a thread-like structure of DNA that carries hereditary information, or genes. Human cells have 22 chromosome pairs plus two sex chromosomes, giving a total of 46 per cell.
The proportion of individuals in a population having a disease or characteristic. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time, whereas incidence refers to the number of new cases that develop in a given period of time.
DNA, or deoxyribonucleic acid, is the main component of chromosomes and the carrier of genetic information in nearly all living organisms. DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C).
A hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome. Genes are transferred from a parent to offspring, and are responsible for the physical and heritable characteristics or phenotype of an individual.
An alteration in the most common DNA nucleotide sequence. The variant can be benign, pathogenic or of unknown significance. SNPs are the most common type of genetic variation.
The genetic makeup of an individual organism. It may also refer to just a particular gene or set of genes carried by an individual. The genotype determines the phenotype, or observable traits of the organism.
The odds ratio is a way of comparing whether the odds of a certain outcome is the same for two different groups. In this report, the odds ratio estimates the probability of a condition occurring in a group of people with a certain genetic variant compared to a group of people without that variant.
An odds ratio of 1 means that the two groups are equally likely to develop the condition. An odds ratio higher than 1 means that the people with the genetic variant are more likely to develop the condition, while an odds ratio of less than 1 means that the the people with the variant are less likely to develop the condition.
A description of an individual’s physical characteristics, including appearance, development and behaviour. The phenotype is determined by the individual’s genotype as well as environmental factors.
POPULATION ALLELE FREQUENCY
The allele frequency represents the incidence of a gene variant in a population. Alleles are variant forms of a gene that are located at the same position, or genetic locus, on a chromosome.
Single nucleotide polymorphisms, frequently called SNPs, are the most common type of genetic variation among people. A SNP is a variation in a single nucleotide that occurs at a specific position in the genome.
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