CBS and myelodysplastic syndrome: The first one consists of the insertion of 68-bp within exon 8 (CBS 844ins68, no rs#) that results in the duplication of a splice site at the intron7/exon 8 junction of the gene (Sperandeo et al., 1996), and two recent literature meta-analyses, both performed with 825 MDS and 1.034 control mothers, failed to find association of the CBS 844ins68 allele and maternal risk of having a DS child (Yang et al., 2013; Balduino Victorino et al., 2014).