The era is characterized by the emergence of population-level newborn screening for metabolic disorders and a growing biochemistry-driven description of inherited conditions. Researchers integrated rapid biochemical assays with epidemiological methods, enabling widespread detection of disorders such as phenylketonuria and related metabolic abnormalities, and laying the groundwork for standardized screening programs. Historical Significance: This period established a durable paradigm that linked early diagnostic capability with genetic and metabolic understanding, catalyzing long‑term management, cross-disease methodological standardization, and the expansion of metabolic genetics as a foundational field.