Validation null values (preconditions)
Why are you using ArgumentNullException? PortalUser isn't an argument, personalData isn't an argument, etc.




PortalUser should be camelcase. 
getPersonalData should be PascalCase. Ditto getUsarioPortalByIdPersonalData. Ditto setuserConsultado (and "User" should be capitalized).
iID_PersonalData should be PascalCase; moreover it seems to be using Hungarian notation which is against the C# standards, and it contains an underscore which is also against the C# standards.




I can't say much about the code, since there's so little of it. It doesn't look that good, to be honest, and I'd certainly move it to a specific method since both blocks seems to be part of a much longer method.