Short answer. Yes. Article 1329 of the Civil Code expressly says the incapacity declared in Article 1327 is subject to modifications determined by law. Special laws can carve out exceptions or adjustments to the general rule, and Article 1327 itself does not bar special disqualifications that other laws establish.
What the law says
The incapacity declared in article 1327 is subject to the modifications determined by law, and is understood to be without prejudice to special disqualifications established in the laws.
Civil Code, Article 1329 — Modifications to Incapacity. Read the full provision →
What Article 1327 provides as the general rule
Article 1327 lists who cannot give consent to a contract: unemancipated minors; insane or demented persons; and deaf-mutes who do not know how to write. A contract entered into by any of these parties is voidable — it can be annulled on the ground of the party's incapacity. This is the baseline rule. Without more, it would bar those groups from all contractual activity except through a guardian or representative.
How Article 1329 opens the door to exceptions
Article 1329 immediately qualifies the baseline with two distinct mechanisms. First, the incapacity declared in Article 1327 is subject to the modifications determined by law. This means the legislature can pass special laws that permit those otherwise incapacitated to enter specific kinds of contracts — within defined limits and for good reasons. For example, laws governing particular industries or relationships may authorize a minor to enter contracts in those specific contexts without triggering the general incapacity rule.
Special disqualifications: the second mechanism
Article 1329 also notes that the general rule is without prejudice to special disqualifications established in the laws. This is the reverse direction: while special laws can loosen the incapacity rules, they can also add disqualifications not found in Article 1327. An otherwise fully competent adult might be disqualified by a specific statute from entering certain contracts — for instance, in conflict-of-interest situations, public office restrictions, or regulated industries. Article 1329 confirms that neither the general incapacity provisions of Article 1327 nor the absence of Article 1327's incapacity prevents such special rules from operating.
Why this matters in practice
If you are dealing with a contract involving a minor or a person with diminished capacity, the question is not only whether Article 1327 applies — but whether any special law modifies it. The same is true if you are dealing with a situation where an otherwise capacitated person might be specially disqualified. Reading only Article 1327 gives you the default; Article 1329 tells you that the default may not be the final answer. Whether a modification or special disqualification applies in your situation depends on the specific contract and the parties involved, and legal advice will help identify which rules govern.