Abstract
IN A PATIENT with NARP (neurogenic weakness, ataxia, and retinitis pigmentosa) syndrome who was followed up for 8 years, we observed the retinopathy progress from a salt-and-pepper appearance to typical retinitis pigmentosa with diffuse peripheral bone spicule formation. At age 13 years, he developed ataxia, and analysis of muscle tissue revealed a mutation at mitochrondrial (mtDNA) nucleotide position 8993. At age 13 years, ophthalmoscopy disclosed salt-and-pepper retinopathy (Figure 1). At age 21 years, his visual fields had become markedly constricted, and ophthalmoscopy disclosed diffuse peripheral bone spicule formation, optic nerve pallor, and arterial attenuation in both eyes (Figure 2). Figure 1. View LargeDownload At age 13 years, the nasal fundus of the patient's left eye demonstrates salt-and-pepper retinopathy. Figure 2. View LargeDownload At age 21 years, the nasal fundus of the patient's left eye demonstrates diffuse peripheral bone spicule formation. Comment The NARP syndrome consists of a combination of neuropathy, ataxia, and retinitis pigmentosa that is caused by a T-to-G–point mutation at nucleotide position 8993 of the mitochondrial DNA, substituting a highly conserved leucine for an arginine residue in the adenosine triphosphatase 6 subunit of complex V.1 Although the characteristic retinopathy is that of bone spicule formation akin to that seen in retinitis pigmentosa, other ophthalmoscopic features that have been reported include a bull's eye maculopathy and salt-and-pepper retinopathy.2 It has been postulated that variability in the ocular and neurologic manifestations of NARP is secondary to heteroplasmy. However, different ocular findings may also represent different stages of disease,3 as seems to be the case in this patient. Patients with retinitis pigmentosa often have mild mottling of the retinal pigment epithelium in the periphery in the early stages of disease, referred to as retinitis pigmentosa sine pigmento. This does not represent a specific entity but rather an early stage of the disease.4 Patients with NARP may have a similar progressive fundus appearance. This work was supported by a grant from the Heed Foundation, Cleveland, Ohio (Dr Kerrison) and as part of an unrestricted grant to the Emory Eye Center, Emory University School of Medicine, Atlanta, Ga, from Research to Prevent Blindness Inc, New York, NY, and core grant P30-EY0 6360 from the National Eye Institute, National Institutes of Health, Bethesda, Md. Corresponding author: Nancy J. Newman, MD, Neuro-ophthalmology Unit, Emory Eye Center, 1365-B Clifton Rd NE, Atlanta, GA 30322 (e-mail: ophtnjn@emory.edu). References 1. Holt IJHarding AEPetty RKH et al. A new mitochondrial disease associated with mitochondrial DNA heteroplasmy. Am J Hum Genet. 1990;46428- 433Google Scholar 2. Ortiz RNewman NJShoffner JM et al. Variable retinal and neurologic manifestations in patients harboring the mitochondrial DNA 8993 mutation. Arch Ophthalmol. 1993;1111525- 1530Google ScholarCrossref 3. Choweres ILerman-Sagie TElpeleg ONShaag AMerin S Cone and rod dysfunction in the NARP syndrome. Br J Ophthalmol. 1999;83190- 193Google ScholarCrossref 4. Weleber RG Retinitis pigmentosa and allied disorders. Retina. St Louis, Mo Mosby–Year Book Inc1994;341- 350Ryan SJOgden TEeds. Basic Science and Inherited Retinal Disease. vol 12nd ed.Google Scholar
Journal
Archives of Ophthalmology
– American Medical Association
Published: Feb 1, 2000
Keywords: retinal diseases,neuropathy, ataxia, and retinitis pigmentosa