Purpose:
To report on an expanded database of occult macular dystrophy patients and to examine the evidence for the presence or absence of a genetic basis for this disease.Background: Occult Macular Dystrophy (OMD) is a rare ocular disease exhibiting bilateral progressive decline in central visual acuity despite a normal fundus exam, fluorescein angiography (FA), and full field electroretinography (ERG). The diagnosis is made when, in addition to the above characteristics, macular function is found to be abnormal by focal or multifocal ERG. It has been postulated that OMD is a unique inherited condition (Miyake et al., 1989 Am. J. Ophthalmol. 108:292). However, reported cases illustrate a variety of multifocal ERG patterns, differences in clinical findings, and many sporadic cases (Lyons, 2005 Doc. Ophthalmol.111(1): 49-56). This suggests the possibility of multiple etiologies giving a similar clinical appearance. In this study we report follow-up data on an expanded database of OMD patients and our work in progress to determine whether our patients have gene defects that could serve as the basis for their disease.
Methods:
A patient database was generated from an individual private practice that serves as a referral center for patients needing ERG testing. Family history of unexplained vision loss was evaluated in all patients. 22 patients and 44 eyes were evaluated clinically, by FA, by visual field testing, and by MERG and full field ERG testing. Patients fulfilling the criteria for OMD were then contacted, informed consent was obtained, and 17 patients were enrolled. Specific genetic mutations screened for through the National Eye Disease Network are listed in Table 1.
Results:
Follow-up data from our enlarged OMD patient database shows patterns of inheritance in some cases while others appear sporadic.
Conclusions:
It makes sense to follow-up with genetic studies to confirm the dual entity nature of this condition. By evaluating the role of specific gene defects we hope to better characterize the disease process and ultimately establish a basis for the disease at which future therapeutic modalities can be directed.
Keywords: genetics • macula/fovea • electroretinography: clinical