They may share a cofactor whose synthesis or transport is defective; they may share a subunit encoded by the mutant gene; they may be processed by a common enzyme whose activity is critical to their becoming active; or they may normally be located in the same organelle, and a defect in the organelle's biological processes can
affect all four enzymes. For example, they may not be imported normally into the organelle and may be degraded in the cytoplasm. Almost all enzymopathies are recessive, and most genes are autosomal.