Identification of Biomarkers by Proteomics for Prenatal Screening for Neural Tube Defects

Neural tube defect (NTD) is a serious congenital defect, but current methods for identifying NTD are limited. We used proteomic analysis of maternal serum to identify NTD-specific proteins whose levels differed between women with NTD fetuses (n = 50) and those with healthy fetuses (n = 40). Three NTD-specific protein peaks (8,130.6, 15,941.7, and 3,960.3 m/z) were identified using MALDI-TOF-mass spectrophotemetry, and were included in a diagnostic model developed using Biomarker Patterns software. The model used cut-offs for the relative intensity of the three peaks to indicate if a case had or did not have NTD. The model identified 48 of the 50 NTD cases and 36 of the 40 control cases correctly, resulting in the sensitivity of 96.0% (48/50) and the specificity of 90.0% (36/40). The diagnostic model was also tested on 105 clinical cases at high risk for NTD, as determined by having high alpha-fetoprotein levels, resulting in the sensitivity of 100% (101/101) and the specificity of 75.0% (3/4). Using the International Protein Index database, we identified proteins with a molecular mass of 8,130.6 Da as ADP-ribosylation factor 1 and a protein similar to cold agglutinin FS-1 antibody light-chain. The 15,941.7-Da peak corresponded to vitamin K3 protein, and the identity of the 3,960.3-Da protein was unclear. Thus, this study developed a diagnostic model consisting of the three peaks which may be indicators of NTD. This new assay may be at least as accurate for diagnosing NTD compared with the commonly used clinical test that assesses alpha-fetoprotein levels.