title: Genetic and Environmental Influences on General Skin Traits: Healthy Twins and Families in Korea.
abstract: Family study can provide estimates of overall genetic influences on a particular trait because family relationships provide accurate measures of average genetic sharing. However, evidence of genetic contributions to skin phenotypes is limited, which may preclude genetic studies to identify genetic variants or to understand underlying molecular biology of skin traits. This study aimed to estimate genetic and environmental contributions to selected dermatologic phenotypes, that is, to melanin index, sebum secretion, and skin humidity level in a Korean twin-family cohort. We investigated more than 2,000 individuals from 486 families, including 388 monozygotic twin pairs and 82 dizygotic twin pairs. Variance component method was used to estimate genetic influences in terms of heritability. Heritability of skin melanin index, sebum secretion, and skin humidity (arm and cheek) were estimated to be 0.44 [95% CI 0.38-0.49], 0.21 [95% CI 0.16-0.26], 0.13 [95% CI 0.07-0.18], and 0.11 [95% CI 0.06-0.16] respectively, after adjusting for confounding factors. Our findings suggest that genetics play a major role on skin melanin index, but only mild roles on sebum secretion and humidity. Sebum secretion and skin humidity are controlled predominantly by environmental factors notably on shared environments among family members. We expect that our findings add insight to determinants of common dermatologic traits, and serve as a reference for biologic studies.
authors.affiliation: Department of Biomedical Sciences,College of Medicine,Inha University,Incheon,Republic of Korea.
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Suh
authors.affiliation: Department of Dermatology,College of Medicine,Inha University,Incheon,Republic of Korea.
authors.forename: Jeonghyun
authors.initials: J
authors.lastname: Shin
authors.affiliation: Department of Epidemiology,School of Public Health,Seoul National University,Seoul,Republic of Korea.
authors.forename: Moonil
authors.initials: M
authors.lastname: Kang
authors.affiliation: Department of Biostatistics,College of Medicine,Yonsei University,Seoul,Republic of Korea.
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Department of Family Medicine,Busan Paik Hospital,Inje University,College of Medicine,Busan,Republic of Korea.
authors.forename: Kayoung
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Family Medicine,Samsung Medical Center,Sungkyunkwan University School of Medicine,Seoul,Republic of Korea.
authors.forename: Yun-Mi
authors.initials: YM
authors.lastname: Song
authors.affiliation: Department of Epidemiology,School of Public Health,Seoul National University,Seoul,Republic of Korea.
authors.forename: Joohon
authors.initials: J
authors.lastname: Sung
mesh_terms: D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008543:Melanins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D056910:Republic of Korea; D012629:Sebum / Q000378:metabolism; D012867:Skin / Q000378:metabolism / Q000503:physiopathology*; D012879:Skin Physiological Phenomena / Q000235:genetics*; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics
chemical_list: D008543:Melanins
keywords: heritability; melanin index; sebum secretion; skin humidity; twins