Novel CYP4V2 gene mutation in a Mexican patient with Bietti's crystalline corneoretinal dystrophy.

PURPOSE: To report the clinical and genetic analysis of a Mexican female patient with a sporadic Bietti's crystalline corneoretinal dystrophy. METHODS: Ophthalmological examination included best-corrected visual acuity, slit lamp examination, applanation tonometry, fundus photography, fluorescein retinal angiography, Goldmann kinetic perimetry, corneal rotating Scheimpflug imaging, and anterior segment optical coherence tomography (Visante OCT). Genetic analysis included PCR amplification and direct nucleotide sequencing of the entire CYP4V2 gene in DNA from the propositus and her relatives. RESULTS: A late-stage retinal dystrophy was established in the patient. No retinal or corneal crystalline deposits were evident during clinical evaluation. Retrospective analysis of fundus imaging disclosed the presence of retinal crystalline deposits, suggesting the diagnosis of Bietti's crystalline corneoretinal dystrophy. Molecular analysis of the CYP4V2 gene revealed the presence of a novel C to T mutation at nucleotide position 974 (exon 7), predicting a threonine to isoleucine replacement at amino acid position 325. Corneal deposits were not seen by biomicroscopy, corneal OCT, or specular microscopy but were evidenced by means of the corneal rotating Scheimpflug imaging. CONCLUSION: Our results expand the allelic heterogeneity of Bietti's crystalline corneoretinal dystrophy. This is the first patient of Latin-American origin in which a molecular analysis of the disease has been performed. Our results suggest that the use of corneal rotating Scheimpflug imaging can evidence corneal deposits that are not apparent by other methods.

Ocular findings in hemoglobin SC disease in Jamaica

In order to structure a series without bias, the retinal and chorioretinal lesions were recorded in a series of 70 Jamaicans with hemoglobin SC disease who were consecutive patients at a sickle cell clinic during a one-month period. By avoiding selective inclusion of cases with ocular pathology, a direct comparison with 76 SS cases studied earlier was possible. An analysis of both series, together indicated that peripheral retinal whitening was associated with mild grades of peripheral retinal vessel disease in 84.3 percent and with severe grades in 47.4 percent, giving rise to the postulation that peripheral whitening reflects an anoxic change, possibly edema, whereas a reddish brown appearance characterizes retinal atrophy associated with more severe vessel disease. Proliferative sickle retinopathy occurred in 63 percent SC paients compared with 26 percent SS patients. The incidence of retinitis proliferans in SC patients was related to hemoglobin level and occurred in 73 percent of patients with hemoglobin levels above 12.5 percent compared to 15 percent of those with hemoglobin below this level. This suggests that an increased blood viscosity may contribute to the development of retinitis proliferans. (Summary)