Figure 1.

Summary of tiered genetic testing approach for 6q24-related transient neonatal diabetes mellitus (TNDM) as suggested by Temple and Mackay [39]. Adapted from and described in further detail in [39]; details of the method for determining the ratio of unmethylated to methylated DNA at 6q24 are in [34]. DMR, differentially methylated region; HIL, hypomethylation at imprinted loci; TNDM, transient neonatal diabetes mellitus; UPD, uniparental disomy. Paternal UPD is established after genotyping a panel of polymorphic markers on chromosome 6q in the parents and offspring and determining that the offspring carries only paternal alleles at each locus.