(A) Organization of the fragile X mental retardation 1 (FMR1) 5′ region, including the cytosine-guanine-guanine (CGG) expansion and primer binding site locations for AmplideX CGG sizing PCR, FastFraX High-Resolution Melt Analysis, and Methylation-Specific Quantitative Melt Analysis (MS-QMA), in relation to Fragile X-Related Epigenetic Element 2 (FREE2); the FMR1 CpG island and methylation sensitive restriction site NruI analysed using routine fragile X Southern blot testing; and two HpaII sites targeted by AmplideX methylation PCR. Note: The FMR1 translation start site is indicated in red overlapping with FastFraX 3′ melting curve analysis (MCA) primer. (B) AmplideX triplet-repeat primed long range PCR results for B1 and B2, for blood, buccal, saliva, and fibroblast DNA. Note: a reference sample co-run with the samples in question is included as the AmplideX sizing control in (B).