RESUMO
BACKGROUND: We previously reported an Ser50Thr mutation in the NRL gene as a cause of autosomal dominant retinitis pigmentosa. OBJECTIVE: To determine the characteristic features of the autosomal dominant retinitis pigmentosa phenotype associated with the NRL Ser50Thr mutation in affected individuals from 4 related families. METHODS: Clinical records were available for 21 affected individuals; 7 underwent more extensive electrophysiologic and psychophysical testing. RESULTS: Night blindness was the first symptom to manifest, with onset between birth and age 16 years. Difficulty with peripheral vision was experienced between 20 and 37 years of age. Visual acuity was well preserved in younger individuals, but those older than 30 years frequently had substantial visual loss (6/36 or worse) associated with macular atrophy. Electrophysiologic testing revealed a nondetectable scotopic electroretinogram with relative preservation of the photopic electroretinogram and pattern electroretinography in the 3 youngest patients tested (aged 15-18 years). In older individuals, all components of the electroretinogram were nondetectable. Dark-adapted visual fields in younger individuals were greatly impaired, but their photopic fields remained relatively well preserved. Older patients had photopic fields limited to just a few degrees. Distinctive peripapillary chorioretinal atrophy seems to develop as the disorder progresses. CONCLUSIONS: The NRL Ser50Thr mutation is associated with selective loss of scotopic function before age 20 years. With time, however, the photopic system becomes affected, leading to loss of the photopic visual field and of visual acuity.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas do Olho/genética , Mutação , Retinose Pigmentar/genética , Retinose Pigmentar/patologia , Adolescente , Adulto , Fatores de Transcrição de Zíper de Leucina Básica , Criança , Adaptação à Escuridão , Eletrorretinografia , Feminino , Angiofluoresceinografia , Humanos , Zíper de Leucina/genética , Masculino , Pessoa de Meia-Idade , Cegueira Noturna/diagnóstico , Cegueira Noturna/genética , Oftalmoscopia , Linhagem , Fenótipo , Células Fotorreceptoras de Vertebrados/fisiologia , Retinose Pigmentar/fisiopatologia , Serina , Treonina , Fatores de Transcrição/genética , Acuidade Visual , Campos VisuaisRESUMO
PURPOSE: To quantify the effect of a fadenoperation to a vertical rectus muscle on the field of binocular single vision (BSV). PATIENTS AND METHODS: BSV was assessed quantitatively in 32 patients before and after a fadenoperation to a single vertical rectus muscle by measuring the vertical extent of single vision in the midline and a score for the total field of BSV. Patients were aged from 14 to 72 years. All patients had diplopia in either downgaze or upgaze before surgery. In 11 patients, this was due to a fourth cranial nerve palsy, and in 8 patients it followed an orbital floor fracture. RESULTS: The 15 patients who had an inferior rectus fadenoperation alone showed a significant mean increase in downward and total vertical extent of BSV and in their field of BSV. The 9 patients who underwent a superior rectus fadenoperation alone showed a significant increase in total vertical extent of BSV and field of BSV score. Three of the 8 who underwent a fadenoperation combined with another strabismus procedure at the same time had a substantial improvement in their score, but after the other 5 showed little change. Patients with a paretic deficit showed substantially more improvement than those with an upgaze deficit after a blowout fracture. CONCLUSION: The fadenoperation to a vertical rectus muscle produced a significant functional expansion in the field of BSV in approximately two thirds of patients. The procedure was more effective in incomitant squints of paretic rather than mechanical etiology.