Table 3.
Relative Penetrance Values for HLA-DR Genotypes[Note]
| Index Cases from | DR2/DR2 | DR2/DRX |
| All familiesa | 11.8 | 3.8 |
| Singleton families onlyb | 9.1 | 2.9 |
| Multicase families onlyc | 20.0 | 6.7 |
Note.— Control genotype frequencies for P/C ratios were derived using nontransmitted alleles from singleton families assuming Hardy Weinberg proportions (Thomson 1995) (DR2 or DRB1*1501-DQB1*0602: f=0.122). Nontransmitted allele frequencies derived using additional trios from multicase families (one per family) were similar (data not shown). All relative penetrance values were normalized to a value of 1 for the reference DRX/DRX genotype.
a
n=549.
b
n=362.
c
n=187.