Gaucher's Disease and Phenylketonuria are identified as potential candidates for genetic therapy due to their genetic origins. Gaucher's Disease results from a deficiency in the enzyme glucocerebrosidase, leading to harmful fatty substance accumulation, while Phenylketonuria is caused by mutations in the PAH gene affecting amino acid metabolism. However, challenges exist for both conditions; Gaucher's gene therapy has shown limited effectiveness due to the lack of growth advantage in treated macrophages, leading to a need for repeated treatments. Phenylketonuria's treatment potential hinges on understanding which cells are affected by the condition. Overall, while both diseases are considered for genetic therapy, significant hurdles remain in their effective treatment.