MALDI-TOF-MS based diagnosis and analysis of newborn hereditary deafness screening in Wuxi, Jiangsu Province

Abstract

Objective To investigate the hot spots of genetic mutations that are responsible for hearing loss of newborns and the carrier frequencies of varies mutations, and also, to set up a clinical pattern for newborn hearing concurrent genetic screening in Wuxi. Methods A total of 2 796 newborns participated in this study were all born in Wuxi Maternity and Child Health Care Hospital during 2013-2014. Twenty hot mutation spots of four genes (i.e. GJB2, GLB3, SLC26A4, 12s rRNA) were chosen according to the latest epidemiologic study and were analyzed with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry ( MALDI-TOF-MS). OAE and AABR methods were both used to help with the diagnosis of newborn hearing loss. Results 158 of 2 796 newborns tested (5.65%) were positive with at least one hot mutation spot. The number of positively tested single site mutation were 152 (5.44%), while the number of positively tested compound heterozygous mutations were 6 (0.21%). The positive mutation sites in GJB2 and SLC26A4 ranked 88.61% among all the positive mutation sites tested. Mutation site 235delC within GJB2 gene were hottest positive site with a number of 73 newborns, followed by IVS7-2A>G within SLC26A4 (18.99%, 30/158). Three 1555A>G homozygous mutations were also found in 12s rRNA. Four deafness newborns were found with newborn hearing concurrent genetic screening. Conclusions In comparison to the conventional detection methods, there could be more detection sites, greater coverage , and high throughput in MALDI-TOF-MS, and it would provid valuable guidance for newborns in the future. Key words: Hearing loss; Connexins; Membrane transport proteins; Mutations; Spectrometry, mass, matrix-Assisted laser desorption-ionization; Neonatal screening