Expression of discoidin domain receptor 1 and E-cadherin in epidermis affects melanocyte behavior in rhododendrol-induced leukoderma mouse model.

Vitiligo is a depigmentation disease characterized by gradual loss of melanin and melanocytes from the epidermis. The mechanism of melanocyte loss is not yet known. In this report, we showed that the expression of discoidin domain receptor 1 and E-cadherin, known adhesion molecules, was variable or absent in the epidermis of rhododendrol-induced leukoderma (RDIL) mice during the depigmentation process.

NGS-based targeted resequencing identified rare subtypes of albinism: Providing accurate molecular diagnosis for Japanese patients with albinism.

Albinism, which is commonly inherited as an autosomal recessive trait, is characterized by a reduction or absence of melanin in the eyes, skin, and hair. To date, more than 20 causal genes for albinism have been identified; thus, the accurate diagnosis of albinism requires next-generation sequencing (NGS). In this study, we analyzed 46 patients who tested negative for oculocutaneous albinism (OCA)1-4 and Hermansky-Pudlak syndrome (HPS)1 based on conventional analysis, in addition to 28 new Japanese patients, using NGS-based targeted resequencing.

Leukoderma induced by rhododendrol is different from leukoderma of vitiligo in pathogenesis: A novel comparative morphological study.

Background: Rhododendrol (rhododenol), an inhibitor of tyrosinase activity, is used as a skin-whitening component. Many cases of leukoderma after the application have been reported, termed rhododenol-induced leukoderma (RIL). The aim of this study was to clarify the pathogenesis of RIL morphologically through comparison with vitiligo.

A 4-bp deletion promoter variant (rs984225803) is associated with mild OCA4 among Japanese patients.

Oculocutaneous albinism (OCA) type 4 is one of the most common types of albinism among Japanese population. In some patients who were clinically diagnosed with OCA, we have found a heterozygous pathological mutation in the coding region of SLC45A2, the gene responsible for OCA4, not leading to a DNA-based diagnosis. In this study, we evaluated pathological variants in the promoter region of SLC45A2 in these patients.

Characterization of melanosomes and melanin in Japanese patients with Hermansky-Pudlak syndrome types 1, 4, 6, and 9.

Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism (OCA), a bleeding tendency, and ceroid deposition. Most of the causative genes for HPS encode subunits of the biogenesis of lysosome-related organelles complex (BLOC). In this study, we identified one patient each with HPS4, HPS6, and HPS9 by whole-exome sequencing.

Microsatellite polymorphism located immediately upstream of the phosphatidylinositol glycan, class K gene (PIGK) affects its expression, which correlates with tyrosinase activity in human melanocytes.

Background: Glycosylphosphatidylinositol (GPI) acts as a membrane anchor and a post-translational modifier for more than 150 proteins (called GPI-anchored proteins: GPI-APs). However, little study has been done to explore the role of GPI-APs in melanocytes.

Methods: The relationship between the mRNA expression of the genes which play essential roles in GPI anchoring system [phosphatidylinositol glycan, class A, and class K gene (PIGA, PIGK)] and melanogenesis-related genes (MITF, TYRP1, TYRP2, and TYR) as well as DOPA oxidase activities were evaluated in 13 different normal human epidermal melanocytes (NHEMs).

Rhododenol-induced leukoderma in a mouse model mimicking Japanese skin.

Background: Rhododendrol, 4-(4-hydroxyphenyl)-2-butanol, Rhododenol(®) (RD), a naturally occurring phenolic compound, was developed as a tyrosinase inhibitor for skin-lightening/whitening cosmetics. In 2013, skin depigmentation was reported in consumers using RD-containing skin-brightening cosmetics; this condition is called RD-induced leukoderma.

Objective: The etiology of RD-induced leukoderma is still largely unknown.