Rapid peptide analysis in dried bloodspots to identify novel markers for newborn screening for congenital hypothyroidism.

Early diagnosis of Congenital Hypothyroidism (CH) is critical to prevent irreversible neurodevelopmental damage. However, current TSH-based newborn screening using Dried Blood Spots (DBS) is limited by factors that lead to false-positive and false-negative results, necessitating the development of alternative methods. Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) as a high-throughput solution was investigated. This study presents a novel diagnostic approach utilizing DBS peptide barcoding, which was supported by comprehensive LC-MS/MS and network analysis. Peptide profiles showed a marked and reproducible difference between groups. MALDI-TOF MS identified a unique signature, including six dominant peptides specific to the CH-positive group. Subsequent analysis identified 37 candidate peptides, with network analysis linking 12 key proteins to established CH-related agents (e.g., thyroxine, TSHR). The MALDI-TOF MS peptidomic approach is validated as a robust, rapid, and cost-effective alternative for CH screening. This methodology represents a significant advance toward overcoming the limitations of current TSH assays and establishing a clinically translatable biomarker panel for improved personalized diagnosis of CH.