Glaucoma is a major cause of blindness and is characterized by progressive degeneration of the optic nerve and is usually associated with elevated intraocular pressure. Analyses of sequence tagged site (STS) content and haplotype sharing between families affected with chromosome 1q-linked open angle glaucoma (GLC1A) were used to prioritize candidate genes for mutation screening. A gene encoding a trabecular meshwork protein (TIGR) mapped to the narrowest disease interval by STS content and radiation hybrid mapping. Thirteen glaucoma patients were found to have one of three mutations in this gene (3.9 percent of the population studied). One of these mutations was also found in a control individual (0.2 percent). Identification of these mutations will aid in early diagnosis, which is essential for optimal application of existing therapies.

Glaucoma is a significant cause of blindness world wide. There is evidence to suggest that at least a subset of the disease is determined genetically. We studied 37 members of a family affected with an autosomal dominant form of juvenile open angle glaucoma and 22 were found to be affected. Linkage analysis using short tandem repeat markers mapped the disease-causing gene to chromosome 1q21-q31. Eight markers were significantly linked (Zmax > 3.0) to the disease, with the highest lod score 6.5 (theta = 0), provided by D1S212. The atrial natriuretic peptide (ANP)/receptor system has been proposed to have a role in glaucoma and one of the ANP receptor genes maps to chromosome 1q.

Macular degeneration is the most common cause of legal blindness in older patients in developed countries. Best's vitelliform dystrophy is an early-onset, autosomal dominant form of macular degeneration characterized by an egg-yolk-like collection of lipofuscin beneath the pigment epithelium of the retinal macula. Fifty-seven members of a five-generation family affected with this disease were studied. A combination of ophthalmoscopy and electro-oculography was used for diagnosis; 29 patients were found to be affected and 16 unaffected. Linkage analysis mapped the disease-causing gene to chromosome 11q13. Three markers in this region were found to be significantly linked (Zmax > 3.0) to the disease. Multipoint analysis yielded a maximum Lod score of 9.3 in the interval between markers INT2 and D11S871.

Butterfly-shaped pigment dystrophy of the fovea is an autosomal dominant eye disease characterized by a bilateral accumulation of yellowish or pigmented material at the level of the retinal pigment epithelium. It shares some clinical and histopathologic features with age related macular degeneration which is the most common cause of legal blindness in older patients. We screened affected patients from a three generation family with butterfly dystrophy for mutations in candidate genes. A base substitution was identified in the peripherin (RDS) gene and DNA sequencing revealed a G to A transition in codon 167 that substitutes aspartic acid for a highly conserved glycine. The mutation segregates with the disease phenotype (Zmax = 4, theta = 0) strongly suggesting that it causes the macular disease in this family.

The two most common autosomal dominant dystrophies of the corneal stroma are lattice corneal dystrophy type I and granular dystrophy. A third autosomal dominant stromal dystrophy (Avellino) has also been recognized. Chromosome linkage analysis of four families with Avellino dystrophy mapped the disease-causing gene to chromosome 5q. Subsequent linkage analysis of two families with typical lattice dystrophy and two with typical granular dystrophy also revealed significant linkage with the same markers. Thus, each of three clinically and histopathologically distinct phenotypes is independently linked to 5q. The maximum combined lod score using all 114 affected patients was 28.6 with marker D5S393. None of the 14 known human amyloid-associated genes map to chromosome 5.