Homozygous mutations in the plasminogen gene of two unrelated girls with ligneous conjunctivitis

Ligneous conjunctivitis is a rare and unusual form of chronic pseudomembranous conjunctivitis that usually starts in early infancy. The disease may be associated with pseudomembranous lesions of other mucous membranes in the mouth, nasopharynx, trachea, and female genital tract. We examined two unrelated Turkish girls both suffering from ligneous conjunctivitis and occlusive hydrocephalus. Both children exhibited a severe plasminogen deficiency. Genomic DNA from both patients as well as from clinically healthy family members were screened for mutations in the plasminogen gene by polymerase chain reaction, single-strand conformation polymorphism (SSCP) analysis, and DNA sequencing. In the first girl with ligneous conjunctivitis a homozygous G-->A point mutation was identified in plasminogen exon 7 at position 780 leading to an amino acid exchange (Arg216-->His). Her healthy sister and her healthy parents were heterozygous for this mutation. The second patient revealed a homozygous G-->A point mutation in plasminogen exon 15 at position 1924 which leads to a stop-codon (Trp597-->Stop). The healthy parents were shown to be heterozygous for this mutation. In addition, the father's second allele revealed another mutation in the same codon (Trp597-->Cys) (compound heterozygosity). In conclusion, certain homozygous mutations in the plasminogen gene may cause ligneous conjunctivitis.