Clinical and genetic features in Italian Bietti crystalline dystrophy patients
- Settimio Rossi1,
- Francesco Testa1,
- Anren Li2,
- Fulya Yaylacioğlu3,
- Carlo Gesualdo1,
- J Fielding Hejtmancik2,
- Francesca Simonelli1
- 1Department of Ophthalmology, Second University of Naples, Naples, Italy
- 2Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
- 3Department of Ophthalmology, Gazi University, Ankara, Turkey
- Correspondence to Dr F Simonelli, Department of Ophthalmology, Seconda Università degli Studi di Napoli, Via S Panini, 5, Naples 80131, Italy;
- Received 13 August 2012
- Revised 16 October 2012
- Accepted 7 November 2012
- Published Online First 6 December 2012
Aim The aim of the study was to describe the clinical and genetic features of 15 Italian patients with Bietti crystalline dystrophy (BCD).
Methods All study participants underwent a complete ophthalmological examination, including standard electroretinogram (ERG), optical coherence tomography, microperimetry, autofluorescence and multifocal electroretinogram. The 11 exons of the CYP4V2 gene were sequenced. The effect of mutations on protein function was estimated by a combination of web based programs.
Results 15 patients (eight women, 7 men, aged 29–60 years) with BCD were recruited into this study. Sequencing of CYP4V2 revealed nine sequence variants in four unrelated families and six isolated individuals with BCD. Seven of these variants were novel. Among the patients, even with the same genotype, considerable variability in phenotypic expression with different degrees of accumulation of the typical intraretinal crystalline deposits was detected. Moreover, we found that more than 50% of patients had recordable standard ERG responses and in two patients the responses were within normal limits after 20 years of symptom onset.
Conclusions In conclusion, we have reported seven new mutations and illustrated the large range of genotypic and phenotypic variability in BCD, highlighting the lack of a clear genotype–phenotype correlation and underlining the existence of less severe clinical manifestations, probably linked to relatively mild mutations.
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