Can I create UClass at runtime?

I want dynamically create new UClass’es. How to do?

Trying to call constructur with FObjectInitializer::Get() causes UE error:

Fatal error: [File:D:\Build\++UE4+Release-4.15+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [Line: 3307]

FObjectInitializer::Get() can only be used inside of UObject-derived class constructor.

I want make my class factory to create new classes with new default values (and propbably with new properties) at runtime…