Given that a clonotype can be public (i.e. present in several individuals) but rare (i.e. of low frequency when compared with other clonotypes), and to address the relevance of GAD-specific clonotypes in blood, we calculated the average frequency of all convergent nucleotide sequences and analysed the frequency distributions of T1D-derived and HD-derived GAD-specific clonotypes in peripheral immune cell subsets. The gene discussed is GAD1; the disease is type 1 diabetes mellitus.