Ptosis, ophthalmoplegia and corneal endothelial disease - ocular manifestations of mitochondrial disease

Abstract

Purpose: To describe two patients with bilateral ptosis, ophthalmoplegia, cataracts and corneal endothelial disease requiring corneal transplantation.

Observations: Histopathological analysis of muscle biopsy samples from both patients identified features consistent with a mitochondrial cytopathy. A single multigenic mitochondrial deoxyribonucleic acid (DNA) deletion was detected in the first patient. Pathogenic mutations in the POLG gene which codes for mitochondrial DNA polymerase, tasked with replicating the mitochondrial genome were identified in the second patient.

Conclusion: The collection of clinical features present in both cases described can be explained by a diagnosis of mitochondrial disease.

Importance: Corneal endothelial disease, in addition to ptosis, ophthalmoplegia, cataract, pigmentary retinopathy and optic atrophy should be recognised as a feature of mitochondrial disease.

Keywords: ATP, Adenosine triphosphate; CHED, Congenital hereditary endothelial dystrophy; COX, Cytochrome oxidase; CPEO, Chronic progressive external ophthalmoplegia; Corneal endothelial disease; DNA, Deoxyribonucleic acid; DSAEK, Descemet's stripping automated endothelial keratoplasty; FECD, Fuchs endothelial corneal dystrophy; LF, Levator palpebrae superioris function; MELAS syndrome, Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke; MRD1, Margin reflex 1 distance; MT-ATP6, Mitochondrially encoded adenosine triphosphate synthase membrane subunit 6; MT-TP, Mitochondrially encoded transfer ribonucleic acid proline; Mitochondrial disease; Ophthalmoplegia; Ptosis; RNA, Ribonucleic acid; SDH, Succinic dehydrogenase; TRNA, Transfer ribonucleic acid.

Fig. 1

Case 1. Haematoxylin and eosin. 200X. A double layer of Descemet's membrane with a marked reduction in endothelial cell density.

Fig. 2

Case 1. Cytochrome oxidase (COX), succinic dehydrogenase (SDH) stain. 200X. COX-negative muscle fibres staining blue interspersed among normal-appearing fibres to create a mosaic pattern. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)