Oculocutaneous albinism (OCA), which is roughly divided into non‐syndromic and syndromic OCA, is a group of autosomal recessive disorders caused by mutations in genes associated with pigmentation. Patients with OCA have hypopigmentation and ocular manifestations such as photophobia, amblyopia, and nystagmus. Hermansky–Pudlak syndrome (HPS), the most common syndromic OCA, is characterized by the additional features of a bleeding tendency and other critical systemic comorbidities such as pulmonary fibrosis and immunodeficiency. NGS‐based gene analyses have identified several new causative genes for OCA and have detected rare subtypes of OCA with high accuracy including Japanese patients. In our survey of 190 Japanese OCA patients/families, OCA4 is the most common subtype (25.3%) followed by OCA1 (20.0%), HPS1 (14.7%), and OCA2 (8.4%). Similar to the A481T variant in OCA2, which is associated with a mild form of OCA2 and skin color variation, the c.‐492_489delAATG variant located in the promoter region of SLC45A2 has been uniquely identified in Japanese patients with a mild form of OCA4. Further, rare OCA subtypes, including OCA3, HPS2, HPS3, HPS4, HPS5, HPS6, and HPS9, have also been identified in Japanese patients. The clinical characteristics and underlying molecular mechanisms of each subtype of OCA are concisely summarized in this review.

中文翻译：

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日本眼皮肤白化病现状

眼皮肤白化病 (OCA) 大致分为非综合征型和综合征型 OCA，是一组由与色素沉着相关的基因突变引起的常染色体隐性遗传疾病。OCA 患者有色素减退和眼部表现，如畏光、弱视和眼球震颤。Hermansky-Pudlak 综合征 (HPS) 是最常见的 OCA 综合征，其特征是出血倾向和其他严重的全身性合并症，如肺纤维化和免疫缺陷等附加特征。基于 NGS 的基因分析已经确定了几个新的 OCA 致病基因，并以高精度检测到了罕见的 OCA 亚型，包括日本患者。在我们对 190 名日本 OCA 患者/家庭的调查中，OCA4 是最常见的亚型 (25.3%)，其次是 OCA1 (20.0%)、HPS1 (14.7%) 和 OCA2 (8.4%)。OCA2，其与OCA2的温和的形式和皮肤颜色的变化相关联，所述C.-492_489delAATG变体位于启动子区SLC45A2已经唯一地在日本患者中鉴定与OCA4的温和的形式。此外，在日本患者中也发现了罕见的 OCA 亚型，包括 OCA3、HPS2、HPS3、HPS4、HPS5、HPS6 和 HPS9。本综述简要总结了各亚型 OCA 的临床特征和潜在分子机制。