A Novel -72 (T→A) β-Promoter Mutation Causing Slightly Elevated HbA₂ in a Vietnamese Heterozygote

Figure 2

Multiplex ligation-dependent probe amplification performed on DNA from proband’s father using SALSA MLPA kit P140-B4 HBA. The horizontal axis shows the MLPA probes arranged according to chromosomal location. The vertical axis shows the normalized probe ratio. White and hatched columns show increased height ratios (~1.2 versus 1 and 1.4 versus 1, resp.). These probe ratios are expected for a heterozygous triplication (product description probemix P140 HBA, MRC-Holland). The HBA(MUT)CS-135 nt probe is specific for the presence of the Constant Spring mutation and does not generate a signal in negative samples.