Retinitis Pigmentosa

Pathophysiology

1) group of different conditions all marked by rod and cone dystrophy 2) most common causes are mutations in genes for peripherin, rhodopsin, and rod photopigment

Signs and Symptoms

1) progressive night blindness 2) loss of visual acuity 3) constriction of visual ring 4) ring scotoma

Characteristic Test Findings

abnormal electroretinogram

Histology/Gross Pathology

“bone spicules” in peripheral retina (not actually bone but an abnormal collection of black pigment)

Associated Conditions

component of – Bassen-Kornzweig syndrome, Kearns-Sayre syndrome, Refsum’s disease, olivopontocerebellar degeneration

Inheritance/Epidemiology

occurs in sporadic, autosomal dominant, autosomal recessive, and X-linked forms

Treatment

1) no effective treatment 2) vitamin A has slight palliative effect but does not affect overall course of disease 3) gene therapy trials are under way

Tips for USMLE

1) name of disease is a misonmer – there is no inflammation in these conditions 2) if question mentions peripherin, think retinitis pigmentosa 3) if question mentions rhodopsin, think retinitis pigmentosa