IMPG2-associated retinitis pigmentosa displays relatively early macular involvement

Ramon A C van Huet, Rob W J Collin, Anna M Siemiatkowska, Caroline C W Klaver, Carel B Hoyng, Francesca Simonelli, Muhammad I Khan, Raheel Qamar, Eyal Banin, Frans P M Cremers, Thomas Theelen, Anneke I den Hollander, L Ingeborgh van den Born, B Jeroen Klevering

Research output: Contribution to journalArticleResearchpeer-review


PURPOSE: To provide the first detailed clinical description in patients with RP caused by recessive mutations in IMPG2.

METHODS: This international collaborative study includes 17 RP patients with inherited retinal disease caused by mutations in IMPG2. The patients were clinically (re-)examined, including extensive medical history taking, slit-lamp biomicroscopy, ophthalmoscopy, perimetry, ERG, optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, fundus photography, and color vision tests. The main outcome measures included mean age at onset, initial symptom, best-corrected visual acuity, fundus appearance, perimetry results, ERG responses, OCT images, FAF imaging, color vision test reports and DNA sequence variants.

RESULTS: The mean age at onset was 10.5 years (range, 4-20 years). Initial symptoms included night blindness in 59% of patients, a decreased visual acuity in 35%, and visual field loss in 6%. Fundus abnormalities were typical of RP: optic disc pallor, attenuated vessels, bone spicules, and generalized atrophy of the retina and choriocapillaris. Additionally, we observed macular abnormalities in all patients, ranging from subtle mottling of the macular pigment epithelium (two patients) and a bull's eye maculopathy (seven patients) to macular chorioretinal atrophy (seven patients).

CONCLUSIONS: Mutations in IMPG2 cause a severe form of RP with symptoms manifesting in the first 2 decades of life. IMPG2-associated RP is frequently accompanied by macular involvement, ranging from mild pigment alterations to profound chorioretinal atrophy. The resulting decrease in central vision in combination with the severe tunnel vision leads to severe visual impairment in patients with IMPG2-associated RP.

Original languageEnglish
Pages (from-to)3939-53
Number of pages15
JournalInvestigative ophthalmology & visual science
Issue number6
Publication statusPublished - 29 May 2014


  • Adult
  • Age of Onset
  • Aged
  • Color Perception Tests
  • Corneal Dystrophies, Hereditary/diagnosis
  • DNA Mutational Analysis
  • Electroretinography
  • Female
  • Genes, Recessive
  • Humans
  • Male
  • Middle Aged
  • Mutation
  • Night Blindness/diagnosis
  • Ophthalmoscopy
  • Pedigree
  • Proteoglycans/genetics
  • Retinitis Pigmentosa/diagnosis
  • Tomography, Optical Coherence
  • Vision Disorders/diagnosis
  • Visual Acuity/physiology
  • Visual Field Tests
  • Visual Fields/physiology
  • Young Adult


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