most alleles were all within a narrow size range this indicates that most class iii alleles have a very similar sequence composition the exception to this were the class iii alleles present in an uncommon haplotype previously referred to as the very protective haplotype vph bennett s t et al 1995 nat genet 9 3 284 292 which were much more thoroughly digested than those from the common protective haplotypes ph bennett s t et al 1995 nat genet 9 3 284 292 resulting in much smaller digestion fragments thus class iii alleles found in the vph are smaller and likely contain more copies of the repeat sequence recognized by mspi than the more common class iii alleles found in the ph the size and mspi analyses were also combined such that class iii alleles were considered as s1 or s2 type alleles only if they matched the s1 or s2 allele respectively in terms of size and mspi rflp pattern alleles were thus designated as s1 or s2 type alleles based on size only mspi rflp only or based on both size and mspi rflp preliminary analysis of transmission disequilibrium in the first 167 samples is summarized in tables 1 3 table 1 shows transmission of alleles determined to be non s1 and non s2 from non diabetic parents to diabetic children as expected they are undertransmitted because of their dominant protective effect and there is no significant.