Compound-Heterozygous Mutations in the Plasminogen Gene Predispose to the Development of Ligneous Conjunctivitis

Homozygous type I plasminogen deficiency has been identified as a cause of ligneous conjunctivitis. In this study, 5 additional patients with ligneous conjunctivitis are examined. Three unrelated patients (1 boy, 1 elderly woman, and 1 man) had plasminogen antigen levels of less than 0.4, less than 0.4, and 2.4 mg/dL, respectively, but had plasminogen functional residual activity of 17%, 18%, and 17%, respectively. These subjects were compound-heterozygotes for different missense mutations in the plasminogen gene: Lys19 → Glu/Arg513 → His, Lys19 → Glu/Arg216 → His, and Lys19 → Glu/Leu128 → Pro, respectively. The other 2 patients, a 14-year-old boy and his 19-year-old sister, who both presented with a severe course of the disease, exhibited plasminogen antigen and functional activity levels below the detection limit (