Expansion of ocular phenotypic features associated with mutations in ADAMTS18.

IMPORTANCE We describe novel ocular phenotypic features caused by mutations in ADAMTS18. The exact role of ADAMTS18 in ocular disease is unclear, and our work further contributes to the understanding of this gene and its protein. OBJECTIVE To expand the phenotypic characterization in patients with homozygous mutations in ADAMTS18 and report novel mutational data. DESIGN, SETTING, AND PARTICIPANTS A case series with genetic investigations was conducted at tertiary referral clinical and university settings. Three families participated. MAIN OUTCOME MEASURES Phenotype and genotype description of 3 families. RESULTS Four affected patients from 3 families with an unusual ocular phenotype had full ophthalmic and systemic examination. A single affected individual in the first family had bilateral microcornea, ectopic pupils, and cone-rod dystrophy. In a second family, 2 brothers showed bilateral microcornea, childhood cataract, ectopia lentis, rhegmatogenous retinal detachment, and cone-rod dystrophy. In the third family, a single affected individual had the same features as those in family 2, without ectopia lentis. Causative mutations were sought using homozygosity mapping, Sanger sequencing, and massively parallel sequencing of the whole exome. Novel homozygous mutations in ADAMTS18 were identified, consisting of c.1067T>A [p.L356*] in the first proband, c.2159G>C [p.C720S] in the 2 affected brothers, and c.1952G>A [p.R651Q] in the third proband. All 3 mutations are predicted to be pathogenic. CONCLUSIONS AND RELEVANCE Mutations in ADAMTS18 are associated with ocular developmental abnormalities including microcornea, ectopia lentis, and early onset of cone-rod dystrophy. This report provides further evidence that ADAMTS18 plays a key role in ocular development. Physicians should consider screening ADAMTS18 in patients with microcornea and cone-rod dystrophy.