Purpose: To report ptosis as an associated finding in 2 patients with maternally inherited diabetes and deafness (MIDD).
Methods: Two unrelated female patients with genetically proven MIDD are described. A complete ophthalmological examination included evaluation of levator muscle function, vertical fissure height and upper lid crease position measurements, the ice pack test and extensive imaging. In addition, pathology of the levator muscle was performed in 1 patient.
Results: The first patient had an asymmetric ptosis at presentation. Levator muscle function was initially normal and decreased 3 years after, suggestive of a myogenic ptosis. Fundus examination revealed a macular pattern dystrophy. The second MIDD patient was referred for bilateral pigment alterations at the posterior pole. Gradually bilateral ptosis developed over a 3-year period. In both patients, ocular motility testing revealed a reduced upgaze.
Conclusions: Myogenic ptosis has been described in association with several of the phenotypes caused by the m.3243A>G mutation, but up to now it had not been described as a finding in MIDD. MIDD has pleomorphic manifestations, and myogenic ptosis should be added to the list of associated clinical features. The additional symmetric elevation deficit in both patients may be an early sign of chronic progressive external ophthalmoplegia (CPEO). The results provide further evidence to suggest that MIDD represents only a part of a continuous spectrum of disease related to the m.3243A>G point mutation in the tRNA(Leu) gene.