Keratoconus associated with Williams-Beuren syndrome: a new case report

Dear Editor, I am Dr. Soraya Mediero, from Department of Ophthalmology of La Paz University Hospital, Madrid, Spain. I write to present a case report of keratoconus associated with Williams-Beuren syndrome (WBS). To our knowledge, this is the fourth report of keratoconus associated with WBS and the first case to be treated with transepithelial cross-linking and corneal segments. And to our knowledge, such a case of WBS associated with megalopapilla has not been previously reported in the literature. INTRODUCTION WBS is a rare genomic multisystem disorder with a prevalence of 1:7500 to 1:10 000. WBS is caused by the contiguous deletion of 26-28 genes, including the elastin gene at 7q11.23. Sporadic inheritance is the most common pattern for this disease, and symptoms typically include dysmorphic facial features, intellectual disability, cardiovascular disease, infantile hypercalcemia, connective tissue disorders and distinctive personality characteristics. The ophthalmologic features described in WBS affect the anterior and posterior segment of the eye and include iris stromal hypoplasia, a clear stellate pattern in the iris, strabismus (usually esotropia and hyperopia), ptosis, congenital cataracts, Marcus-Gunn phenomenon, reduced stereoacuity and retinal vascular tortuosity. The optic nerve is exceptionally affected by this syndrome and can suffer disc hypoplasia and increased disc excavation. Keratoconus is a fairly common bilateral, non inflammatory, degenerative axial ectatic condition of the cornea that progresses to corneal thinning, increasingly irregular astigmatism and the onset of corneal opacities. The prevalence of keratoconus in the general population ranges from 8.8 to 54.4 per 100 000 inhabitants, but its association with WBS is very rare. In fact, the case of keratoconus reported below is the fourth associated with WBS reported to date. CASE REPORT A 23-year-old man was referred to our center 3y ago due to a progressive decline in visual acuity over 2y. He had been diagnosed with WBS by deletion of chromosome 7q11.23 at the age of 5 years, initially suspected by the pediatric neurologist, and subsequently confirmed by fluorescent in situ hybridisation (FISH) analysis with the elastin Williams syndrome chromosome region (WSCR) probe (Oncor). The patient presented dysmorphic facial features and mild intellectual disability, but there were no associated connective tissue disorders. At that time, his uncorrected visual acuity was 20/20 in the right eye (RE) and 20/400 in the left eye (LE), and the best spectacle-corrected visual acuity was 20/60 in the LE. Refraction was -1.25/-2.00×67 in the RE and -9.25/-13.00×154 in the LE. The slit-lamp examination showed no abnormalities in the RE; however, the LE cornea showed a Fleischer’s iron ring and Vogt’s striae. The iris, lens and pupillary reaction were normal. The intraocular pressure measured with Goldmann tonometer was 12 mm Hg in the RE and 8 mm Hg in the LE. Ultrasonic pachymetry showed a central corneal thickness of 433 μm in the RE and 345 μm in the LE. Funduscopy revealed a megalopapilla with a vertical diameter of 2.72 mm, a vertical cup-to-disc ratio of 0.8 in the RE (Figure 1) Keratoconus and Williams-Beuren syndrome