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。

In human being, tyrosinase is the key enzyme for melanin biosynthesis, and is associated with melanin hyperpigmentation such as melasma, freckles, ephelide, senile lentigines.

在人体中，它与色素障碍性疾病及恶性黑色素肿瘤的发生与治疗有关。