In Italian an article is almost always mandatory before a possessive. The exceptions are:
- when the possessive adjective is alone following a form of "essere," e.g. è mio (it's mine);
- in a small number of set phrases, e.g. casa mia (my home);
- before close family members, in the singular and not modified, e.g. "mio padre" (my father), unless the possessive is "loro" (in which case the article is needed). However, if we are talking about a family member in diminutive form (e.g. fratellino, little brother; mammina, mommy; zietta, auntie, etc.) we do use the definite article.