Immunologic studies of cartilage-hair hypoplasia in the Amish.

The immunologic status of 18 Old Order Amish persons with cartilage-hair hypoplasia and 9 unaffected sibs was studied. Although none of the subjects had a history suggestive of persistent immune dysfunction, the subjects with cartilage-hair hypoplasia had significantly lower lymphocyte mitogenic and allogeneic cell stimulation responses when compared to unaffected sibs and unrelated control subjects. The abnormalities of cellular immune function found in the 18 affected subjects were similar to those reported in Finnish subjects with cartilage-hair hypoplasia.