Molecular genetics of achromatopsia in Newfoundland reveal genetic heterogeneity, founder effects and the first cases of Jalili syndrome in North America.
Achromatopsia (ACHM) is a severe retinal disorder characterized by an inability to distinguish colors, impaired visual acuity, photophobia and nystagmus. This rare autosomal recessive disorder of the cone photoreceptors is best known for its increased frequency due to founder effect in the Pingelapese population of the Pacific islands. Sixteen patients from Newfoundland, Canada were sequenced for mutations in the four known achromatopsia genes CNGA3, CNGB3, GNAT2, and PDE6C. The majority (n = 12) of patients were either homozygotes or compound heterozygotes for known achromatopsia alleles, two in CNGB3 (p.T383fsX and p.T296YfsX9) and three in CNGA3 (p.R283Q, p.R427C and p.L527R). Haplotype reconstruction showed that recurrent mutations p.T383fsX and p.L527R were due to a founder effect. Aggregate data from exome sequencing, segregation analysis and archived medical records support a rediagnosis of Jalili syndrome in affected siblings (n = 4) from Family 0094, which to our knowledge is the first family identified with Jalili Syndrome in North America.
Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
Lance
L
Doucette
Jane
J
Green
Coleman
C
Black
Jeremy
J
Schwartzentruber
Gordon J
GJ
Johnson
Dante
D
Galutira
Terry-Lynn
TL
Young
D003119:Color Perception Tests; D003117:Color Vision Defects / Q000208:ethnology / Q000235:genetics*; D003241:Consanguinity; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6 / Q000235:genetics; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics; D004596:Electroretinography; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D018703:Founder Effect; D018740:Genetic Heterogeneity; D006239:Haplotypes; D006801:Humans; D006983:Hypertrichosis / Q000235:genetics*; D057130:Leber Congenital Amaurosis / Q000235:genetics*; D008297:Male; D008967:Molecular Biology; D009154:Mutation; D009523:Newfoundland and Labrador / Q000453:epidemiology; D010375:Pedigree; D012174:Retinitis Pigmentosa / Q000235:genetics*; D015293:Transducin / Q000235:genetics; D014792:Visual Acuity; D058609:Visual Field Tests; D044465:White People / Q000208:ethnology
C518238:CNGA3 protein, human; C415904:CNGB3 protein, human; D054815:Cyclic Nucleotide-Gated Cation Channels; D005136:Eye Proteins; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; C096885:PDE6C protein, human; D015293:Transducin