Purchase this article with an account.
S. George, D.G. Frazer, G. Silvestri, J. Jackson; Phenotypic Analysis of Familial Keratoconus and Developmental Cataract in a Large Irish Pedigree . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5553.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To analyse the clinical phenotype in three generations of an Irish family with early onset autosomal dominant keratoconus and cataract.
The investigators visited 48 members of a three generation Irish family affected with severe, early onset keratoconus and developmental cataract, on separate occasions spanning an 11 year period. The majority of the pedigree lived in remote rural Ireland, necessitating domicillary visits by the investigators for clinical assessment of patients. Comprehensive ophthalmic and medical history were documented for each patient. Examination on each occasion comprised slit lamp biomicroscopy, keratometry, full refraction and direct ophthalmoscopy. Corneal topography was performed on those patients demonstrating corneal surface irregularities.
All family members were developmentally normal, except one patient with microphthalmia and congenital cataract. There was no history of cosanguinity. Of the full complement of 63 relatives, 14 are affected with keratoconus and anterior polar cataract, 1 with keratoconus alone and 2 with only developmental cataract. Keratoconic retinoscopy reflexes first manifest between the ages of 9–11 years, in keeping with the first appearance of cones at 10 years of age. Six family members progressed to keratoplasty for keratoconus, 2 having unilateral and 4 having bilateral corneal grafting. The first signs of anterior polar lens opacity tended to predate the development of cones by 1–2 years. In the five patients who required both cataract extraction and corneal grafting, cataract surgery preceeded keratoplasty in all cases except one where combined surgery was performed. In total, nine patients underwent cataract surgery, all in early adulthood. Assessment of the second and third generation demonstrated that if no signs of keratoconus or cataract were evident by the early teenage years, the patient would remain disease free.
The genotype analysis for this family has previously been reported, the causative gene being linked to chromosome 15. This study presents the first clinical description of familial keratoconus and associated developmental cataract in the literature. Ophthalmic features occurred in the absence of systemic abnormality. The severity of the keratoconus is unusual, almost 50% of affected individuals having progressed to keratoplasty. Examination of the younger individuals clearly illustrates the chronology of the disease.
This PDF is available to Subscribers Only