ABSTRACT
PURPOSE: To evaluate visual impairment in Finnish Usher syndrome type 3 (USH3) and compare this with visual impairment in Usher syndrome types 1b (USH1b) and 2a (USH2a). METHODS: We carried out a retrospective study of 28 Finnish USH3 patients, 24 Dutch USH2a patients and 17 Dutch USH1b patients. Cross-sectional regression analyses of the functional acuity score (FAS), functional field score (FFS*) and functional vision score (FVS*) related to age were performed for all patients. The FFS* and FVS* were calculated using the isoptre V-4 test target instead of the usual III-4 target. Statistical tests relating to regression lines and Student's t-test were used to compare between USH3 patients and the other genetic subtypes of Usher syndrome. RESULTS: Cross-sectional analyses revealed significant deterioration in the FAS (1.3% per year), FFS* (1.4% per year) and FVS* (1.8% per year) with advancing age in the USH3 patient group. At a given age the USH3 patients showed significantly poorer visual field function than the USH2a patients. CONCLUSIONS: The rate of deterioration in visual function in Finnish USH3 patients was fairly similar to that in Dutch USH1b or USH2a patients. At a given age, visual field impairment in USH3 patients was similar to that in USH1b patients but poorer than in USH2a patients.
Subject(s)
Usher Syndromes/physiopathology , Vision Disorders/physiopathology , Visual Acuity/physiology , Visual Fields/physiology , Adolescent , Adult , Child , Cross-Sectional Studies , Finland , Genotype , Humans , Middle Aged , Phenotype , Retrospective Studies , Usher Syndromes/genetics , Visual Field TestsABSTRACT
PURPOSE: To assess the risk of retinoblastoma developing in children with microscopic chromosomal with mosaic deletions involving 13q14. DESIGN: Case report and systematic literature review. PARTICIPANTS: Data on 29 patients with a mosaic and 107 patients with a nonmosaic somatic deletion of chromosome 13q14 were compared. MAIN OUTCOME MEASURES: Age at diagnosis, frequency, and laterality of retinoblastoma. CASE REPORT: A dysmorphic baby, who carried a chromosomal deletion involving 13q14 in 34% of peripheral blood lymphocytes, had neuroradiologic evidence of retinoblastoma at the age of 2 weeks. She developed trilateral retinoblastoma, a pineal neuroblastic tumor, at the age of 10 months. The diagnosis of her tumor was delayed because of misjudgment of risk of retinoblastoma developing. RESULTS: Meta-analysis revealed no difference between children with mosaic and nonmosaic chromosomal deletion of 13q14 regarding the age at diagnosis, laterality of tumor, and presence of family history for retinoblastoma. A lower percentage of somatic cells with mosaic deletion did not predict a higher age at diagnosis or unilateral tumors. No statistically significant difference was noted regarding the presence of mental retardation, dysmorphic features, and anomalies of internal organs between mosaic and nonmosaic deletions. Only 7% (95% confidence interval, 1-23) of 29 patients who had a mosaic chromosomal deletion including 13q14 were not reported to develop retinoblastoma. CONCLUSIONS: Whenever a 13q14 deletion is diagnosed, immediate ophthalmologic evaluation is recommended to ensure prompt diagnosis of retinoblastoma. Mosaic and nonmosaic chromosomal deletions of 13q14 do not differ regarding the risk and type of retinoblastoma developing.
