Solar lentigines, the other types of freckles, occur among old people regardless of skin colour.
日光性着色斑是一种其它类型的雀斑，发生在老年人中，与肤色无关。
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In human being, tyrosinase is the key enzyme for melanin biosynthesis, and is associated with melanin hyperpigmentation such as melasma, freckles, ephelide, senile lentigines.