CNGA3 mutations in two United Arab Emirates families with achromatopsia.
OBJECTIVE
ACHROMATOPSIA RESULTS FROM MUTATIONS IN ONE OF THREE GENES: cyclic nucleotide-gated channel, alpha-3 (CNGA3); cyclic nucleotide-gated channel, beta-3 (CNGB3); and guanine nucleotide-binding protein, alpha-transducing activity polypeptide 2 (GNAT2). We report the responsible mutations in two United Arab Emirates families who have this autosomal recessive disease.


METHODS
Clinical examinations were performed in seven patients from three nuclear families. Molecular genetic testing for common CNGA3 and CNGB3 mutations was undertaken using standard protocols.


RESULTS
All patients were extremely light sensitive and had reduced visual acuity and no color perception. Fundus examinations did not show any visible abnormalities. After further pedigree analysis, two of the families were found to be linked through the paternal line. Two mutations in CNGA3 were identified: Arg283Trp and Gly397Val. Family A, the larger pedigree, had one branch in which two sisters and one brother were homozygous for the Gly397Val mutation and another branch in which a brother and sister were compound heterozygous for both aforenamed mutations. Family B, however, only had two brothers who were homozygous for the Arg283Trp mutation.


CONCLUSIONS
Achromatopsia in these two United Arab Emirates families results from two different mutations in CNGA3. Two branches of the same pedigree had individuals with both homozygous and compound heterozygous disease, demonstrating a complex molecular pathology in this large family.
Ahuja
Yachna
Y
Center for Genetic Eye Diseases, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
Kohl
Susanne
S
Traboulsi
Elias I
EI
D000293:Adolescent; D018912:Arabs / Q000235:genetics*; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D003117:Color Vision Defects / Q000235:genetics*; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics*; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005190:Family; D005260:Female; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D014479:United Arab Emirates
C518238:CNGA3 protein, human; D054815:Cyclic Nucleotide-Gated Cation Channels