Abbreviations:

Down syndrome (DS) Immunoglobulin G (IgG Immunoglobulin G heavy chain gene4 (IGHG4 )
Quantitative real-time polymerase chain reaction (qPCR)
Immunoglobulin heavy constant G2 (IGHG2 )
Immunoglobulin heavy constant E (IGHE )
pulsed field gel electrophoresis technique (PFGE)
comparative genomic hybridization (array CGH)