Alpha2-macroglobulin deficiency in a patient with Ehlers-Danlos syndrome.

A new genetic defect, alpha2-macroglobulin deficiency, was found in a patient with Ehlers-Danlos syndrome (EDS). Other members of the family of five exhibiting this abnormality were the mother and one sister. All members, including the patient, had normal serum albumin and alpha1-antitrypsin levels. The deficiency, reported here for the first time, appears to be inherited by an autosomal co-dominant mode. Statistical evaluation of the dihybrid crosses for independent assortment between EDS and hypo-alpha2-macroglobulinemia showed a probability of 0.7 to 0.75. However, a possible link between EDS and hypo-alpha2-macroglobulinemia is suggested since the observed ratios of four siblings are exactly as expected, assuming that double gene defects are linked in the mother's genotype.