Hypotheses can be made concerning the effects of mutations in the genes encoding RAPGEF1 (accelerated T1D) and ZFP583, CCDC13, CD200R1 and ATRNL1 (delayed T1D), but are exceedingly speculative because known functions of these proteins (if any) do not fit neatly within the current framework for T1D etiology. Here, CCDC13 is linked to type 1 diabetes mellitus.