Brittle cornea syndrome: An heritable connective tissue disorder distinct from Ehlers-Danlos syndrome type VI and fragilitas oculi, with spontaneous perforations of the eye, blue sclerae, red hair, and normal collagen lysyl hydroxylation

Abstract

We report a patient with the characteristic features of the brittle cornea syndrome, a rare, autosomal recessively inherited disorder, namely brittle corneae, blue sclerae, and red hair. The patient also showed joint hyperextensibility, a soft skin, and dysplastic auricles with unusually soft cartilage. Phenotypically, the disorder bears a certain resemblance to fragilitas oculi and the type VI (ocular) form of the Ehlers-Danlos syndrome, two conditions which are, themselves, not readily distinguishable. However, the hydroxylysine content of dermal collagen was normal, as was the activity of lysyl hydroxylase in cultured dermal fibroblasts, thus supporting the distinction of the brittle cornea syndrome as an independent entity. No abnormality was discernible in types I or III collagens synthesised by cultured fibroblasts, but electron microscopy revealed dramatic ultrastructural alterations in dermis in that distributed over its whole thickness were 20–60 μm wide “holes” or fibre-free spaces, filled with an amorphous material.