An epidemiological approach for the estimation of disease onset in Central Europe in central and peripheral monogenic retinal dystrophies.

PURPOSE: To study clinical patterns of disease onset in monogenic retinal dystrophies (MRD), using an epidemiological approach. METHODS: Records of patients with MRD, seen at the University Eye Hospital Tuebingen from 1994 to 1999, were selected from a database and retrospectively reviewed. For analysis, patients were divided into 2 groups by predominant part of visual field (VF) involvement: group 1 (predominantly central involvement) included Stargardt disease (ST), macular dystrophy (MD), and central areolar choroidal dystrophy (CACD), and group 2 (predominantly peripheral involvement) included Bardet-Biedl syndrome (BBD), Usher syndrome (USH) I and II, and choroideremia (CHD). Age, sex, age of first diagnosis, age of visual acuity (VA) decrease and VF emergence, night blindness and photophobia onset, types of VF defects and age of its onset, color discrimination defects and best corrected VA were analyzed. RESULTS: Records of 259 patients were studied. Men were more prevalent than women. Mean age of the patients was 47.2 (SD = 15.6) years old. Forty-five patients in the first group and 40 in the second were first diagnosed between 21 and 30 years of age. Ninety-four patients in the first group had VA decrease before 30 years of age; in the second group, 68 patients had VA decrease onset between 21 and 40 years of age. Forty-four patients in the first group noticed VF at an age between 21 and 30 years, and 74 patients between 11 and 30 years in the second group. Central scotoma was typical for the first group, and was detected in 115 patients. Concentric constriction was typical for the second group, and was found in 81 patients. Half of patients in both groups preserved best-corrected VA in the better eye at a level of 20/40 or better; 7% in the first group and 6% in the second group were registered as legally blind according to WHO criteria, having VA <1/50 or VF <5 degrees . Diagnosis frequency was USH I and II-34%, ST-31%, MD-18%, CHD-14%, BBD-5%. CONCLUSIONS: An epidemiological approach to the estimation of the disease onset of various subtypes of monogenic retinal degenerations will be useful for detection of disease duration, its prognosis, rehabilitation and the researching of future treatment possibilities.