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The glaucomas are a group of diseases characterized by optic nerve damage that together represent a leading cause of blindness in the human population and in domestic animals. Here we report a mutation in LTBP2 that causes primary congenital glaucoma (PCG) in domestic cats. We identified a spontaneous form of PCG in cats and established a breeding colony segregating for PCG consistent with fully penetrant, autosomal recessive inheritance of the trait. Elevated intraocular pressure, globe enlargement and elongated ciliary processes were consistently observed in all affected cats by 8 weeks of age. Varying degrees of optic nerve damage resulted by 6 months of age. Although subtle lens zonular instability was a common feature in this cohort, pronounced ectopia lentis was identified in less than 10% of cats examined. Thus, glaucoma in this pedigree is attributed to histologically confirmed arrest in the early post-natal development of the aqueous humor outflow pathways in the anterior segment of the eyes of affected animals. Using a candidate gene approach, significant linkage was established on cat chromosome B3 (LOD 18.38, θ = 0.00) using tightly linked short tandem repeat (STR) loci to the candidate gene, LTBP2. A 4 base-pair insertion was identified in exon 8 of LTBP2 in affected individuals that generates a frame shift that completely alters the downstream open reading frame and eliminates functional domains. Thus, we describe the first spontaneous and highly penetrant non-rodent model of PCG identifying a valuable animal model for primary glaucoma that closely resembles the human disease, providing valuable insights into mechanisms underlying the disease and a valuable animal model for testing therapies.

In a pedigree developed from affected Abyssinian cats, an early onset rod-cone dysplasia (Rdy) was identified and demonstrates an autosomal dominant inheritance. This is an excellent model for inhe...

White fur or coat pigmentation and the presence of blue eyes have been linked to cochleosaccular deafness in multiple mammalian species. At this time, no hereditary explanation has been presented for this phenotype as it appears in horses. A candidate gene study was established to determine the genetic basis for this disorder in a pedigree of Spanish Mustangs. KIT, a receptor tyrosine kinase implicated in multiple mammalian deafness studies, was sequenced in both the affected Spanish Mustangs and related members of the pedigree. A mutation (KI16 + 1037A) in the 5’ splice junction of exon 17 known to cause the sabino coat pattern appeared to be unlinked from the deafness phenotype. Sabino coloration is distinguished as a white coat, ranging from minimal white splashes to an entirely white mammal. Future research will focus on the sequencing of additional candidate genes affecting melanocyte migration and melanin production, including EDNRB, MITF, PMEL17, and SOX10.Grant Funding Source: Supported by HHMI