Lack of the HLA-DR2 specificity in multifocal choroiditis and panuveitis.

The prevalence of the HLA-B7 and HLA-DR2 specificities in 17 unrelated patients with multifocal choroiditis and panuveitis, 11 with and six without subretinal neovascularisation, was evaluated and compared with those of two different groups. The first group was 17 patients with subretinal neovascularisation associated with presumed ocular histoplasmosis syndrome, and the second was a group of 105 eye patients with no retinal disease. HLA-DR2 was not found in any patient with multifocal choroiditis and panuveitis, but it was found in 13 patients with presumed ocular histoplasmosis syndrome (p = 6.72 x 10(-5), comparison of the groups with subretinal neovascularisation). The lack of HLA-DR2 was also significant in comparison with the control group of eye patients (p = 0.041). This study suggests that patients with multifocal choroiditis and panuveitis and presumed ocular histoplasmosis syndrome have differing genetic predispositions, though the fundus pictures in these entities have many similarities.

Magnetic resonance imaging morphology of the corpus callosum in monozygotic twins.

Recent reports describe wide variations in the size and shape of the human corpus callosum. To investigate genetic influences on this variability, magnetic resonance images from 5 pairs of monozygotic twins and 10 unrelated control subjects were analyzed. Measurements of size and shape revealed greater similarity in twin pairs than in randomly paired controls. The results are consistent with the view that the anatomy of the corpus callosum, while clearly influenced by nongenetic factors, is under considerable genetic control.