As a bit of Canadian content, a team of researchers at the
University of Calgary apparently just announced that they've
discovered a gene for it. A news item on it appeared in Canadian
newspapers on October 31, 2000.
See http://www.canoe.ca/Health0010/31_blindness-cp.html
I say "apparently" because if you go the University of Calgary
website ( http://www.rpresearch.ca/vw1f-81.htm), it turns out the
news dates back to an article in Nature Genetics in 1998.
But it seems that this news refers to a follow-up study in the
same journal. Here's the abstract.
-Stephen
Nat Genet 2000 Nov;26(3):319-323
Mutations in NYX, encoding the leucine-rich proteoglycan
nyctalopin, cause X-linked complete congenital stationary night
blindness.
Bech-Hansen NT, Naylor MJ, Maybaum TA, Sparkes RL, Koop B, Birch
DG, Bergen AA, Prinsen CF, Polomeno RC, Gal A, Drack AV,
Musarella MA, Jacobson SG, Young RS, Weleber RG
Department of Medical Genetics, Faculty of Medicine, University
of Calgary, Calgary, Alberta, Canada.
During development, visual photoreceptors, bipolar cells and
other neurons establish connections within the retina enabling
the eye to process visual images over approximately 7 log units
of illumination. Within the retina, cells that respond to light
increment and light decrement are separated into ON- and
OFF-pathways. Hereditary diseases are known to disturb these
retinal pathways, causing either progressive degeneration or
stationary deficits. Congenital stationary night blindness (CSNB)
is a group of stable retinal disorders that are characterized by
abnormal night vision. Genetic subtypes of CSNB have been defined
and different disease actions have been postulated. The molecular
bases have been elucidated in several subtypes, providing a
better understanding of the disease mechanisms and developmental
retinal neurobiology. Here we have studied 22 families with
'complete' X-linked CSNB (CSNB1; MIM 310500; ref. 4) in which
affected males have night blindness, some photopic vision loss
and a defect of the ON-pathway. We have found 14 different
mutations, including 1 founder mutation in 7 families from the
United States, in a novel candidate gene, NYX. NYX, which encodes
a glycosylphosphatidyl (GPI)-anchored protein called nyctalopin,
is a new and unique member of the small leucine-rich proteoglycan
(SLRP) family. The role of other SLRP proteins suggests that
mutant nyctalopin disrupts developing retinal interconnections
involving the ON-bipolar cells, leading to the visual losses seen
in patients with complete CSNB.
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Stephen Black, Ph.D. tel: (819) 822-9600 ext 2470
Department of Psychology fax: (819) 822-9661
Bishop's University e-mail: [EMAIL PROTECTED]
Lennoxville, QC
J1M 1Z7
Canada Department web page at http://www.ubishops.ca/ccc/div/soc/psy
Check out TIPS listserv for teachers of psychology at:
http://www.frostburg.edu/dept/psyc/southerly/tips/
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