Variation in human skin and hair color is the most notable aspect of human variability and several studies in evolution, genetics and developmental biology contributed to explain the mechanisms underlying human skin pigmentation, which is responsible for differences in skin color across the world's populations. Despite skin pigmentation is primarily related to melanocytes functionality, the surrounding keratinocytes and extracellular matrix proteins and fibroblasts in the underlying dermal compartment actively contribute to cutaneous homeostasis. Many autocrine/paracrine secreted factors and cell adhesion mechanisms involving both epidermal and dermal constituents determine constitutive skin pigmentation and, whenever deregulated, the occurrence of pigmentary disorders. In particular, an increased expression of such mediators and their specific receptors frequently lead to hyperpigmentary conditions, such as in melasma and in solar lentigo, whereas a defect in their expression/release is related to hypopigmented disorders, as seen in vitiligo. All these interactions underline the relevant role of pigmentation on human evolution and biology.
Biology ; Cell Adhesion ; Developmental Biology ; Extracellular Matrix Proteins ; Fibroblasts ; Genetics ; Hair Color ; Homeostasis ; Humans ; Intercellular Signaling Peptides and Proteins ; Keratinocytes ; Lentigo ; Melanocytes ; Melanosis ; Pigmentation ; Skin Pigmentation* ; Skin* ; Vitiligo

Molecular identification of human externally visible characteristic （EVC）, which is also called forensic DNA phenotyping （FDP）, can serve as a "molecular witness" when the routine investigations can not determine the identity of a criminal and the DNA database find no match after comparison. FDP could assist in investigation of cases by inferring the externally visible phenotypic characteristics from DNA obtained from the biological materials left at crime scenes, or unknown corpses. In the last few years, studies on the selection of EVC related molecular markers have been reported frequently and some of the EVCs could already be inferred with a certain accuracy, such as hair color and iris color. Further fundamental research on molecular genetics of human external phenotypic characteristics, as well as the continuous innovation on molecular biological technology would promote the rapid development of DNA molecular identification of human phenotypic characteristics.
DNA/genetics* ; Databases, Nucleic Acid ; Eye Color/genetics* ; Forensic Anthropology/trends* ; Forensic Genetics/trends* ; Hair Color/genetics* ; Humans ; Phenotype ; Physical Appearance, Body/genetics* ; Skin Pigmentation/genetics*

Objective To predict the pigmentation phenotypes of Chinese populations from different language families, analyze the differences and provide reference data for forensic anthropology and genetics. Methods The HIrisPlex-S multiplex amplification system with 41 loci related to pigmentation phenotypes was constructed in the laboratory, and 2 666 DNA samples of adult males of 17 populations from six language families, including Indo-European, Sino-Tibetan, Altaic, Hmong-Mien, Tai-Kadai and Austro-Asiatic language families distributed in different regions of China were genotyped. The pigmentation phenotype category of each individual was predicted using the online prediction system （https://HIrisPlex.erasmusmc.nl/）, and then the output data were statistically analyzed. Results About 1.92% of the individuals of Asian-European admixed populations from Indo-European and Altaic language families had blue eyes and 34.29% had brown or gold hair. The phenotypes of the color of eyes and hair of other populations had no significant difference, all individuals had brown eyes and black hair. There were differences in skin color of populations of different language families and geographical areas. The Indo-European language family had the lightest skin color, and the Austro-Asiatic language family had the darkest skin color; the southwestern minority populations had a darker skin color than populations in the plain areas. Conclusion The prediction results of pigmentation phenotype of Chinese populations are consistent with the perception of the appearance of each population, proving the reliability of the system. The color of eyes and hair are mainly related to ancestral components, while the skin color shows the differences between language families, and is closely related to geographical distribution of populations.
Adult ; Asian People/genetics* ; China ; Eye Color/genetics* ; Forensic Anthropology ; Forensic Genetics/methods* ; Humans ; Language ; Male ; Phenotype ; Polymorphism, Single Nucleotide ; Reproducibility of Results ; Skin Pigmentation/genetics*

BACKGROUNDThe dyschromatoses are a group of disorders characterized by simultaneous hyperpigmented macules together with hypopigmented macules. Dyschromatosis universalis hereditaria (DUH) and dyschromatosis symmetrica hereditaria are two major types. While clinical and histological presentations are similar in these two diseases, genetic diagnosis is critical in the differential diagnosis of these entities.

METHODSThree patients initially diagnosed with DUH were included. The gene test was carried out by targeted gene sequencing. All mutations detected on ADAR1 and ABCB6 genes were analyzed according to the frequency in control database, the mutation types, and the published evidence to determine the pathogenicity.

RESULTSFamily pedigree and clinical presentations were reported in 3 patients from two Chinese families. All patients have prominent cutaneous dyschromatoses involving the whole body without systemic complications. Different pathogenic genes in these patients with similar phenotype were identified: One novel mutation on ADAR1 (c. 1325C>G) and one recurrent mutation in ABCB6 (c. 1270T>C), which successfully distinguished two diseases with the similar phenotype.

CONCLUSIONTargeted gene sequencing is an effective tool for genetic diagnosis in pigmentary skin diseases.

ATP-Binding Cassette Transporters ; genetics ; Adenosine Deaminase ; genetics ; Adolescent ; Asian Continental Ancestry Group ; Child ; Diagnosis, Differential ; Female ; Genetic Predisposition to Disease ; genetics ; Humans ; Male ; Pedigree ; Pigmentation Disorders ; congenital ; diagnosis ; genetics ; RNA-Binding Proteins ; genetics ; Skin Diseases, Genetic ; diagnosis ; genetics

OBJECTIVETo analyse the mutation of ADAR gene in a pedigree with dyschromatosis symmetrical hereditaria (DSH).

METHODSA pedigree of DSH was investigated. Mutation scanning was carried out by PCR and direct sequencing. ADAR gene of 50 normal people was also sequenced as control. Through CBMdisc and PubMed, the mutations of ADAR gene were summarized.

RESULTSA novel mutation of c.2447G > A was found in all patients with DSH, but was not found in normal individuals in this DSH family and 50 unrelated controls. There were 64 mutations in ADAR gene.

CONCLUSIONA deletion mutation (c.2447G > A) in the ADAR gene has been detected in this DSH family, which is probably one of the molecular bases of the pathogenesis of the disease. Author have summarized a total of 64 mutations in the ADAR gene by previous reports and speculate that the mutation hotspots of ADAR gene might be located in the tRNA-specific and double-stranded RNA adenosine deaminase (ADEAMc) domain.

Adenosine Deaminase ; genetics ; Adult ; Base Sequence ; DNA Mutational Analysis ; Female ; Genetic Predisposition to Disease ; genetics ; Humans ; Male ; Mutation ; Pedigree ; Pigmentation Disorders ; genetics ; Polymerase Chain Reaction ; RNA-Binding Proteins ; Skin Diseases, Genetic ; genetics

To elucidate the genes responsible for constitutive human skin color, we measured the extent of skin pigmentation in the buttock, representative of lifelong non-sun-exposed skin, and conducted a gene mapping study on skin color in an isolated Mongolian population composed of 344 individuals from 59 families who lived in Dashbalbar, Mongolia. The heritability of constitutive skin color was 0.82, indicating significant genetic association on this trait. Through the linkage analysis using 1,039 short tandem repeat (STR) microsatellite markers, we identified a novel genomic region regulating constitutive skin color on 11q24.2 with an logarithm of odds (LOD) score of 3.39. In addition, we also found other candidate regions on 17q23.2, 6q25.1, and 13q33.2 (LOD > or = 2). Family-based association tests on these regions with suggestive linkage peaks revealed ten and two significant single nucleotide polymorphisms (SNPs) on the linkage regions of chromosome 11 and 17, respectively. We were able to discover four possible candidate genes that would be implicated to regulate human skin color: ETS1, UBASH3B, ASAM, and CLTC.
Adolescent ; Adult ; Asian Continental Ancestry Group/*genetics ; Child ; *Chromosome Mapping ; Color ; Female ; Genome-Wide Association Study ; Humans ; Male ; Mongolia ; Pedigree ; Polymorphism, Single Nucleotide ; Skin/metabolism ; *Skin Pigmentation ; Young Adult

The mechanisms of estrogen and progesterone in human cutaneous pigmentation are largely unknown. The molecular identification of estrogen receptor (ER) and progesterone receptor (PR) in the human melanocytes is of great importance to understand the mechanisms. We performed immunocytochemistry analysis and demonstrated that ER and PR were expressed in the cytoplasms and nuclei of human melanocytes. Reverse transcriptase-polymerase chain reaction (RT-PCR) and sequence analysis confirmed the expression of ER and PR at the transcriptional level. Despite of the presence of ER and PR, the physiological and pregnant levels of estrogen and progesterone showed inconsistent effects on the proliferation and tyrosinase activity of cultured human melanocytes. These results suggest that human melanocytes express ER and PR, which have a donor-specific action in human pigmentation. Further studies are needed to elucidate the induction mechanism and functions of these receptors, and the role of estrogen and progesterone in melanocytes.
Adult ; Cells, Cultured ; Estrogens/*pharmacology ; Gene Expression ; Humans ; Melanocytes/cytology/*drug effects/metabolism ; Mitogens/pharmacology ; Organ Culture Techniques ; Progesterone/*pharmacology ; Receptors, Estrogen/genetics/*metabolism ; Receptors, Progesterone/genetics/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Skin/drug effects ; Skin Pigmentation/drug effects ; Tissue Donors