Epidemiological characteristics and clinical phenotype of sporadic retinitis pigmentosa

Background Retinitis pigmentosa (RP) is a group of progressive monogenic inheritance disease.Seldom epidemiology is performed to summarize the varied clinical phenotypes,especially some sporadic cases with untypical genetic history. Objective The aim of this survey was to investigate the clinical epidemiological characteristics and phenotype of sporadic RP. Methods A prospective cohort study was designed.A survey of a series of clinically diagnosed sporadic primary RP patients was conducted at the Southwest Eye Hospital from July 2010 to November 2011.A total of 130 patients that matched the inclusion criteria were enrolled in this survey.Clinical ocular examinations and questionnaire surveys were given,including ophthalmoscopic examination,best corrective visual acuity( BCVA ),perimetry and Ganzfield electroretinogram (ERG)and color fundus photo.RP with different phenotypes were classified. Results A total of 130 sporadic RP patients were collected in this survey.Of them,66 were male and 64 were female with a mean age of (36.9±14.4) years.The average onset age of these subjects was (21.2±18.4) years.Seven (5.38％) patients had consanguineous marriage history,and 13 ( 10.00％ )patients had systemic disease.Forty-four (33.85％) patients had outdoor jobs,and 86 (66.15％ ) worked indoor.Eighty-nine patients had typical RP ( 68.5％ ),and the number of patients that developed central RP and sine pigmento RP were 16 ( 12.3％ ) and 16( 12.3％ ),respectively.An absence of a- and b-waves in full-field ERG was detected in 99 (76.15％ ) cases.The longest duration of night blindness was identified in typical RP patients and the lowest BCVA in central RP patients. Conclusions The age at first onset is early in sporadic RP.There are wide variations in different types of RP,but the ERG outcome is specific for all RP types. Key words: Retinitis pigmentosa/sporadic; Epidemiological characteristics; Phenotype; Full-field electroretinogram; Questionnaire