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Ophthalmic Genet. 2002 Jun;23(2):109-20.

Clinical features of achromatopsia in Swedish patients with defined genotypes.

Author information

1
Department of Ophthalmology, University Hospital, Lund, Sweden. louise.eksandh@telia.com

Abstract

PURPOSE:

To describe the clinical phenotype, with emphasis on the electrophysiological findings, of patients with autosomal recessive rod monochromacy (RM) and defined mutations in the CNGA3/CNGB3 genes.

METHODS:

RM patients from eight different families were included in the study. Their genotypes were determined by DNA sequencing and/or RFLP analysis of PCR-amplified genomic segments of the CNGA3 and CNGB3 genes. For comparison, we investigated one patient with blue-cone monochromacy (BCM). The clinical examination included best-corrected visual acuity, fundus examination, and full-field ERG. In six patients, the examination was complemented by multifocal ERG (MERG).

RESULTS:

Three patients had three different CNG3A genotypes. Five patients were homozygous and one patient compound heterozygous for a 1-bp deletion (1148delC) in the CNGB3 gene. All patients examined presented with a visual acuity of 0.1-0.15. Small residual cone responses were noted in four young RM patients. The oldest patient examined (age 47 years) presented with pigmentary changes in the mid-peripheral retina and concentric constrictions of the visual fields.

CONCLUSIONS:

Patients with RM and mutations in the CNGA3/CNGB3 genes presented a similar clinical phenotype, confirming the essential function of both the alpha- and beta-subunits of the cGMP-gated cation channel in cone photoreceptor function. Small remaining cone responses in a few of the younger patients and mid-peripheral pigmentary degenerations in the oldest patient examined indicate that there could be some degree of progression in retinal dysfunction in at least some patients with RM.

PMID:
12187429
[Indexed for MEDLINE]

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