Note: Descriptions are shown in the official language in which they were submitted.
CA 02517218 2005-08-25
MARKER FOR PSYCHOSIS OR MOOD DISORDER
FIELD OF INVENTION
[0001] The present invention relates to diagnosis or identifying a risk of
developing
psychosis, a mood disorder, or both psychosis and a mood disorder. More
particularly,
the present invention relates to association of a genetic marker with
psychosis, a mood
disorder, or both psychosis and a mood disorder.
BACKGROUND OF THE INVENTION
[0002] Mood disorders, for example, bipolar disorder or schizophrenia are
common,
chronic mental illnesses. Bipolar disorder manifests primarily as a
disturbance of
1o mood, sometimes accompanied by psychotic symptoms, whereas the core
features of
schizophrenia are psychosis and cognitive impairment.
[0003] The N-methyl-D-aspartate receptor (NMDAR) has been hypothesized to play
a
crucial role in the pathophysiology of both psychotic symptoms and disease
progression in schizophrenia. The ability of NMDAR antagonists to induce a
15 syndrome closely resembling schizophrenia suggests that dysfunction or
dysregulation
of NMDAR-mediated neurotransmission could play a role in schizophrenia.
Several
investigators have examined mRNA expression patterns for individual NMDA
receptor subunits, including NR2B, in schizophrenia with somewhat conflicting
results (Akbarian et al. 1996; Grimwood et al. 1999). These findings suggest
that
2o further investigation of the role of NR2B in schizophrenia is needed.
[0004] In bipolar disorder, lithium and valproate are the most well
established mood
stabilizers used for tong-term treatment. Both of these drugs have a
neuroprotective
effect through reducing NMDAR-induced excitotoxicity, suggesting that
alterations of
glutamatergic transmission and/or of NMDARs may be involved in the symptoms of
25 bipolar disorder.
[0005] The gene encoding Glutamate Receptor Ionotropic, N-methyl-D-aspartate
2B
(GRIN2B), a subunit ofNR2B, has been localized to chromosome 12p12 . The full
length GRIN2B cDNA has been cloned and sequenced in mouse, and has 90%
homology with the human gene sequence (Schito et al. 1997). Previous attempts
to
CA 02517218 2005-08-25
detect an association between GRIN2B and schizophrenia have produced
inconsistent
results (Nishiguchi et al. 2000; Ohtsuki et al. 2001, Di Maria et al, 2004).
More
specific phenotypes have been studied in association with GRIN2B
polymorphisms: a
positive association was found between the C2664T polymorphism and higher
clozapine dosage in 100 Chinese treatment refractory patients (Hong et al.
2001).
These results were replicated in another sample consisting of 193 treatment-
refractory
schizophrenic patients and 176 normal subjects (Chiu et al. 2003).
[0006] Miyatake et al (2002) studied a T-to-G variant at nucleotide position -
200 of
the 5'UTR of GRIN2B. This substitution shortens the dinucleotide repeat to:
(GT)6(CT)(GT)6, and alters the putative Spl binding site. Luciferase reporter
assays
with transfected cell-lines demonstrated that the G-variant is associated with
lower
gene activity (Miyatake et al. 2002). A comparison between 100 Japanese
schizophrenics and 100 Japanese controls showed that the frequency of the G
allele
was significantly higher in schizophrenics.
[0007] In the rat and human, the NR2B subunit is primarily expressed in
forebrain
structures, such as the cortex, hippocampus, striatum, thalamus, and olfactory
bulb.
Most of the studies on changes in expression levels of NMDAR subunits have
focused
on the subunit NRl (encoded by the GRIN 1 gene). A higher level of binding to
NRl/NR2B receptors has been reported in superior temporal cortex in
schizophrenia
(Grimwood et a1.1999). Gao et al (2000) analyzed postmortem hippocampal tissue
from schizophrenia and healthy individuals and showed that NMDAR mRNA levels
for NRl were lower, and for NR2B higher in schizophrenia, in several
hippocampal
subregions (Gao et al. 2000).
[0008] In bipolar disorder, there has been relatively little investigation of
the
hippocampal glutamatergic system. Law and Deakin (2001) report a decrease in
NRl
mRNA in subjects with bipolar disorder. While Benes et al. (2001) showed no
change
in the lowaffinity kainate receptor subunits in subjects with bipolar
disorder. A third
study reported a decrease of activated hippocampal NMDAR but no change in the
expression of kainate or AMPA in eight subjects with Bipolar Disorder (Scam et
al.
2003).
CA 02517218 2005-08-25
[0009] There is a need to further clarify the association between mood
disorders and
GRIN2B or GRIN2B variants.
SUMMARY OF THE INVENTION
[0010] The present invention relates to diagnosis or identifying a risk of
developing
psychosis, a mood disorder, or both psychosis and a mood disorder. More
particularly,
the present invention relates to association of a genetic marker with
psychosis, a mood
disorder, or both psychosis and a mood disorder.
[0011] It is an object of the invention to provide an improved method of
diagnosing
psychosis, a mood disorder, or psychosis and a mood disorder, or identifying a
risk of
1o developing psychosis, a mood disorder, or psychosis and a mood disorder
based on
testing of the GRIN2B gene or related gene products.
[0012] According to the present invention there is provided a method (A) of
diagnosing or identifying susceptibility of a subject to a mood disorder
comprising,
testing a sample obtained from the subject for the presence of a polymorphism
in the
15 NMDAR subunit gene GR1N2B, wherein the presence of allele C of the T/C
polymorphism at nucleotide position 5988 indicates that the patient is
susceptible to a
mood disorder. A non-limiting example of a mood disorder is Bipolar Disorder.
[0013] The present invention also provides a method (B) of diagnosing or
identifying
susceptibility of a subject to psychosis comprising, testing a sample obtained
from the
2o subject for the presence of a polymorphism in the NMDAR subunit gene
GRIN2B,
wherein the presence of allele C of A/C polymorphism at nucleotide position
5806
indicates that the patient is susceptible to psychosis. Furthermore, psychosis
is a set
of symptoms that may be associated with a variety of illnesses including, but
not
limited to, Schizophrenia, Alzheimer's Disease, Major Depressive Disorder,
25 Schizoaffective Disorder, or Bipolar Disorder.
[0014] The present invention also pertains to a method (C) of diagnosing or
identifying susceptibility of a subject to a mood disorder comprising, testing
a sample
obtained from the subject for the presence of a haplotype in the NMDAR subunit
gene
GRIN2B, wherein the combined presence of allele T of T/G polymorphism at the
CA 02517218 2005-08-25
nucleotide position -200 (minus 200), allele C of A/C polymorphism at
nucleotide
position 5806, and allele C of the T/C polymorphism at nucleotide position
5988
indicates that the patient is susceptible to a mood disorder. A non-limiting
example of
a mood disorder is Bipolar Disorder.
[0015] This summary of the invention does not necessarily describe all
features of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other features of the invention will become more apparent
from the
following description in which reference is made to the appended drawings
wherein:
[0017] FIGURE 1 shows a schematic diagram of the location of polymorphisms in
GR1N2B in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0018] The present invention relates to diagnosis or identifying a risk of
developing
psychosis, a mood disorder, or both psychosis and a mood disorder. More
particularly,
the present invention relates to association of a genetic marker with
psychosis, a mood
disorder, or both psychosis and a mood disorder.
[0019] The following description is of a preferred embodiment.
[0020] The present invention provides a genetic marker that may be used to
diagnose
a mood disorder or identify a susceptibility to a mood disorder. As described
in more
detail below, specific polymorphisms in the GRIN2B gene may be used as an
indicator of a mood disorder, for example, but not limited to bipolar
disorder.
Additionally, altered levels of GRIN2B mRNA or altered levels of NR2B protein
may
be used as an indicator of a mood disorder, for example, but not limited to
bipolar
disorder. Furthermore, a genetic marker is provided that may be used to
diagnose
psychosis or identify susceptibility to psychosis. Polymorphisms in the GRIN2B
gene,
CA 02517218 2005-08-25
altered levels of GRIN2B gene products, or a combination thereof, may be used
as an
indicator for psychosis.
[0021] In examples of the present invention a subject's GRIN2B gene or related
gene
products is assayed or tested to diagnose a mood disorder or identify a
susceptibility to
a mood disorder. An example of a mood disorder includes, without limitation,
bipolar
disorder, major depressive disorder (unipolar depression), dysthymia,
cyclothymia, or
depression co-morbid with another illness.
[0022] In certain examples of the present invention a subject's GRIN2B gene or
related gene products is assayed or tested to diagnose psychosis or identify a
1o susceptibility to psychosis. Psychosis is a set of symptoms that may be
associated with
a variety of illnesses including, but not limited to, Schizophrenia,
Alzheimer's
Disease, Major Depressive Disorder, Schizoaffective Disorder, or Bipolar
Disorder.
[0023] In certain examples, specific polymorphisms in the GRIN2B gene are used
as
an indicator of psychosis, a mood disorder, or psychosis and a mood disorder.
In other
15 examples, altered levels of GRIN2B mRNA are used as an indicator. In still
other
examples, altered levels of NR2B protein are used as an indicator.
[0024] The results of assaying the GRIN2B gene or related gene products may be
used
alone or in conjunction with other clinical tests. In one example, a
susceptibility to
Bipolar Disorder can be identified by assaying for a T5988C polymorphism in
the 3'
2o UTR of the GRIN2B gene. In another example, susceptibility to psychosis may
be
identified by assaying for an A5806C polymorphism in the 3'UTR of the GRIN2B
gene. In still another example, results of a clinical psychiatric test, such
as without
limitation SC>I7 (Structured Clinical Interview for Diagnostic and Statistical
Manual
Diagnosis) or FIGS (Family Interview for Genetic Studies), may be considered
in
25 conjunction with the results of assaying for a GRIN2B polymorphism.
[0025] Any tissue sample may be used for genotyping GRIN2B polymorphisms,
including but not limited to, saliva or blood. In certain examples, blood is
obtained
from a subject for assaying with respect to GRIN2B polymorphisms. In an
example,
venous blood is obtained from a subject using standard venipuncture
techniques.
CA 02517218 2005-08-25
[0026] A subject's DNA is assayed for GRIN2B polymorphisms DNA. The method
of obtaining and analyzing DNA is not critical to the present invention and
any
methods may be used (e.g. Ausubel, et al. (eds), 1989, Current Protocols in
Molecular Biology, Green Publishing Associates, Inc., and John Wiley & Sons,
Inc.,
New York, at p. 2.10.3, or Maniatis et al., in Molecular Cloning (A Laboratory
Manual), Cold Spring Harbor Laboratory, 1982, p. 387-389). For example, which
is not to be considered limiting in any manner, DNA may be extracted using a
non-
enzymatic high-salt procedure (Lahiri and Nurnberger 1991). Alternatively, the
DNA
may be analyzed in situ. Other methods of DNA analysis that are known to
persons
skilled in the art may also be used.
[0027] With reference to examples pertaining to assaying GRIN2B polymorphisms,
examples of single nuclear polymorphism (SNP) indicators are at position -
200G/T
located in the 5' UTR of GR1N2B, at position 5806A/C or 5988T/C located in the
3'
UTR of GRIN2B (see Figure 1).
15 [0028] Polymorphisms may be genotyped using conventional techniques. For
example, PCR using primers incorporating fluorescent probes is one suitable
technique. For example, which is not to be considered limiting, primers having
the
following sequences:
forward primer: 5'-TCGCAGGCACTATTCTAACTACTTTAC (SEQ ID NO:1)
2o reverse primer: 3'GCATTCCTGAAAAGAGAGATCATGTG (SEQ ID N0:2)
may be used for the G-200T marker;
for the A5806C marker the following sequences may be used:
forward primer: 5'-GCTACAGAGCAGACAGTTAAGAGAA (SEQ ID N0:3)
reverse primer: 3'TCATGGAGTGCAGCTCATTTCT (SEQ ll~ N0:4); and
25 for the T5988C marker, the following sequences may be used:
forward primer: 5'-CTTGAGCCCAGAGTGAACACT SEQ ID NO:S)
CA 02517218 2005-08-25
reverse primer: 3'ACCCTCATCCCTGGAGTTTTATACA (SEQ iD N0:6).
[0029] A sample from a subject can be assayed for comparing or quantifying
GRIN2B
mRNA levels, NR2B protein, or both GRIN2B mRNA levels and NR2B protein
levels. Samples may be obtained from a variety of tissue sources. For example,
in
post-mortem analysis brain tissue, such as without limitation, hipoocampus,
superior
temporal cortex, or dorsolateral prefrontal cortex (Brodmann's area 46) may be
assayed. In living subjects, if brain tissue is unavailable then other samples
such as
white blood cells can be assayed.
[0030] Expression levels of GRIN2B mRNA may be measured using any standard
to technique, for example without limitation, Northern analysis, quantitative
PCR using
Cyclophilin A levels as a control comparison and calculating expression levels
of
GR1N2B as a ratio of GRIN2B/cyclophilin threshold cycle (Tc) values, and the
like.
[0031] Levels of NR2B protein may also be measured using any variety of
techniques
known to the skilled person, for example without limitation, ELISA,
15 immunodiffusion, or other methods that are known to one of skill in the
art.
[0032] The subject may be a human or an animal subject. For example, other
mammals that may be tested include, but are not limited to a dog, cat, horse,
mouse,
rat, or cow.
[0033] The present invention will be further illustrated in the following
examples.
20 Examples
Example 1: Genotynin~ of living subiects
[0034] Subjects were recruited with fully informed written consent, and in
accordance
with University of Toronto and Canadian Institutes of Health Research (C1HR)
guidelines for the ethical treatment of human subjects.
25 [0035] A total of 86 nuclear families consisting of probands with
schizophrenia and at
least one first degree relative were collected from hospitals in Toronto,
Ontario. In
addition, 192 schizophrenia case-control pairs were recruited. All patients
had an
independent clinical DSMIIIR / DSM-N diagnosis of schizophrenia from their
CA 02517218 2005-08-25
referring psychiatrist. (American Psychiatric Association 1994) A SC>D
(Structured
Clinical Interview for DSM diagnosis) was administered by trained research
assistants
to each proband to confirm a DSM-IIIR diagnosis of schizophrenia. After review
of
all clinical information, consensus between two experienced psychiatrists was
the
final decision for diagnosis. Controls were screened using the FIGS (Family
Interview
for Genetic Studies) and screening questions from the SCID, and excluded if
there
was any personal or family history of major mental illness or
alcohol/substance abuse.
Patients and control subjects were matched for age +/- 5 years, sex, and self
reported
ethnicity to reduce the potential stratification that might result from
ethnically
1o heterogeneous case and control groups. The average age was 37 years; with a
male:
female ratio of 162:180; greater than 95% of the subjects were Caucasian. The
case-
control sample is 100% Caucasian, so as to avoid issues of population
stratification.
[0036] Venous blood was obtained from subjects using standard venipuncture
techniques. DNA was extracted using a non-enzymatic high-salt procedure
(Lahiri and
15 Nurnberger 1991 ).
[0037] The bipolar trio sample consisted of 318 nuclear families from the
Toronto
area. The SCID interview and the same diagnostic procedures were used as
above.
The average age of the probands was 41; the male: female ratio was 565:479;
and
greater than 95% were Caucasian. The sample is further divided in two groups:
triads
2o with psychotic probands (N=158) and triads with non-psychotic probands
(N=160).
[0038] Three SNP markers in the GRIN2B gene were studied: G-200T, A5806C and
T5988C. The G-200T marker is located in the S'UTR, whereas the A5806C and the
T5988C markers are located in the 3'UTR (see figure 1). The A5806C marker and
T5988C are in partial linkage disequilibrium. All three polymorphisms were in
Hardy-
25 Weinberg equilibrium.
[0039] Polymorphisms were genotyped using fluorescent TaqMan~ probes as part
of
commercial Assays-on-DemandTM SNP Genotyping assays on the ABI PRISM 7000
sequence detection system, according to the manufacturer's protocol (Applied
Biosystems Inc., Foster City, CA). The primer sequences were used:
3o for the G-200T marker (ABI catalogue # 4332072):
CA 02517218 2005-08-25
Forward primer: 5'-TCGCAGGCACTATTCTAACTACTTTAC SEQ ID NO:1
Reverse primer: 3'GCATTCCTGAAAAGAGAGATCATGTG (SEQ ID N0:2);
for the A5806C marker (ABI catalogue # 4332072):
forward primer: 5'-GCTACAGAGCAGACAGTTAAGAGAA (SEQ ID N0:3)
reverse primer: 3'TCATGGAGTGCAGCTCATTTCT (SEQ m N0:4); and
for the T5988C marker (ABI catalogue # 4332072):
forward primer: 5'-CTTGAGCCCAGAGTGAACACT (SEQ ID NO:S),
reverse primer: 3'ACCCTCATCCCTGGAGTTTTATACA (SEQ m N0:6).
[0040] The PCR protocol was as follows: DNA lpl; TaqMan MasterMix Spl; Assay
10 0.25p1; dH20 3.75p1. Cycling conditions were as follows: after 10 min at
95°C, the
samples were submitted to 40 cycles, each consisting of a step at 95°C
for 15 s,
followed by a step at 60°C for 1 min. The PCR product was detected as
an increase in
fluorescence during the PCR extension phase when the probe was cleaved by the
5'
exonuclease activity of the Taq DNA polymerase. This cleavage interrupts the
fluorescence resonance energy transfer and the reporter dye starts to
fluoresce in
proportion to the level of PCR product generated.
[0041] The informative polymorphisms and the haplotype distribution were
tested in
the schizophrenia and bipolar nuclear family samples using the family based
association tests (FBAT; Laird et al. 2000). Differences in the allele
frequencies
2o between the patients and healthy controls were tested using the chi-square
association
test. Haplotype distributions in our case-control sample were obtained using
Cocaphase.
[0042] Eighty six nuclear families (triads) composed of father, mother and
schizophrenia proband, as well as a sample of 192 schizophrenia case-control
pairs,
matched for age, gender, and ethnic background were genotyped for the GRIN2B (-
200)G/T, (5806)A/C and (5988)T/C markers. The allele count for each marker in
this
sample is listed in Table 1. Markers were also tested for association with
bipolar
CA 02517218 2005-08-25
11
disorder in a sample of 318 nuclear families composed of father, mother and
bipolar
proband. The size of this bipolar sample allowed subdivision and testing of
the
markers for association with the specific subphenotype of psychotic symptoms
in the
proband.
Table 1: Genotype counts and results for the case-control sample
T-2006 A58 06C T5988C
Cases T/T=19 A/A=16 TrT=9
T/G=74 A/C=82 TIC=40
G/G=71 C/C=54 C/C=94
Controls TIT=31 A/A=19 T/T=7
T/G=93 A/C=55 TIC=47
GIG=34 C/C=55 C/C=86
Xz (df=2) 17.9 2.373 0.849
74
p-value (corrected)_ ~ p= ~ P=
0.0003 0.305 0.654
[0043] Markers were found to be in Hardy-Weinberg Equilibrium. For the T-2006
polymorphism: a significant association of the G allele with the disease in
the
1 o schizophrenia case- control sample was found; for the G/G genotype (data
not shown)
as well as for the presence of the G allele. The result is still significant
after correcting
for multiple testing. The nuclear families were tested for association using
FBAT,
showing no preferential transmission of either allele. Combining the z scores
from the
nuclear families and the Case-Control (zl+z2/~2) (Hedges 1985), an overall
15 significant result was obtained (See table 2 and table 3).
Table 2: P-value results for the combined SCZ samples.
T-2006 GIG GenotypeG allele
Case-Control p<0.0001 P<0.0001
Corrected for muIt. =0.0003 P=0.0003
test.
Case-Contr. + triad ~p=0.0009 P=0.0027
[0044] The bipolar nuclear families were also tested using FBAT; no
significant
2o association was found between the GltIN2B gene -200T/G marker and the
entire
bipolar sample, or with the subphenotype samples, that is, presence of
psychotic
symptoms (See table 3).
CA 02517218 2005-08-25
12
Table 3: Chi-square, and FBAT results for the Case Control, schizophrenia
(SCZ) and bipolar disorder (BP) triad samples for all markers.(S): observed
transmission;E(S): expected transmission.
T-2006 A5806C T5988C
Case-ControlXz=17.974; Xz=2.373; p=0.305Xz=0.849; p=0.654
p=0.0003
N=200
airs
SCZ Triadsz=0.775 p=0.44z=0.349; p=0.73z=0.6; p= 0.56;
S=25/11;
(N=86 S=26/25; S=15/25; E(S)=23.6/12.3;
IT=16
edi rees E S =26.7/27.21T=26E S =15.8/24.1;
IT=18
BP TriadsZ=0.898; p=0.37z= 0.395; p=0.69;z=2.332; p=0.02
(N=318 S=163/157 S=140/172 S=60/144;
pedigrees)E(S)=167.66/153.33E(S)=137.1/174.9E(S)=70.7/133.21T=98
IT=154 IT=150
After correction
for mutt.
Test. p=0.04
BP Psychoticz= 0.101; p=0.9z= 2.892; p=0.0038z=1.945; p=0.051
(N=158 S=80/66; S=60/104; S=27/45; E(S)=34.9/67.1;
pedigrees)E(S)=76.5/69.5E(S)=75.7/88.2;IT=48
IT=70 IT=74
After correction
for mutt.
Test. p=0.008
[0045] No association was found between the A5806C polymorphism and our
schizophrenia samples (both triads and case-control). The overall analysis of
the
bipolar sample with A5806C gave negative results. However, an over
transmission of
allele C was detected in bipolar patients with psychotic symptoms, even after
to correction for multiple testing (Table 3).
[0046] For the T5988C polymorphism: no association was found between the
marker
and schizophrenia in case control and both nuclear family samples. The
analysis of the
bipolar sample showed a preferential transmission of allele C in the complete
bipolar
sample, but with either one of the subgroups the level of significance drops
to a trend.
15 The significance is lost after correction for multiple testing. (Table 3).
[0047] Haplotype analyses was performed for these markers with results listed
in
tables 4 and 5. A preferential transmission of haplotype T-C-C in the bipolar
sample
was detected.
Table 4: BP sample haplotype analyses using FBAT.
CA 02517218 2005-08-25
13
HAP Haplotype AI. Z scorep-value ObservedExpected
freq. (S) E(S)
H 1 T C C 2 2 0.2182.411 0.01589991.752 80.402
1
H2 T A C 1 2 0.209-0.995 0.31995769.888 74.627
1 )
H3 G C C 2 2 0.202-1.103 0.26982966.696 71.862
2)
H4 G A C 1 2 0.1531.326 0.18487663.664 58.275
2)
H5 T C T (2 1 0.100-1.742 0.08757328.208 33.852
1)
H6 G C T 2 1 0.072-0.758 0.44866518.344 20.555
2)
H7 T A T (1 1 0.026***** *****
1 )
H8 ~ G A T (1 0.021***** *****
1 2) ~ ~ ~
Table 5: SCZ trio sample haplotype analyses using FBAT.
HAP Haplotype AI. Z scorep-valueObservedExpected
freq. (S) E(S)
H1 T A C (1 0.239 1.169 0.24245221.579 18.655
1 2)
H2 T C C (1 0.218 -0.031 0.97519017.421 17.503
2 2)
H3 G A C (2 0.200 0.986 0.32421318.421 16.512
1 2)
H4 G C C (2 0.172 -0.453 0.65071416.579 17.497
2 2)
H5 T C T 1 0.096 -1.633 0.1024516.000 9.842
2 1)
H6 G C T (2 0.075 0.006 0.9953958.000 7.991
2 1 ) ~ ~
[0048] Haplotype analyses on the schizophrenia case control sample also showed
significant increase of haplotype G-C-T in cases, and of haplotype T-C-C in
controls
(Table 6).
Table 6: schizophrenia case-controls sample haplotype analysis.
HaplotypeCases Controls p value*
EM Frequency**HaplotypeEM Frequency**
T A T 0.000279
TAC 0.2119 1,1,2 0.1782 0.116
T C T 0.1539 1,2,1 0.1229 0.271
T C C 0.2026 1,2,2 0.2751 0.01
G A T 0.008576
G A C 0.1366 2,1,2 0.1978 0.013
G C T 0.114 2,2,1 0.05462 0.008
G C C 0.1405 ( 2,2,2 0.1703 0.104
~
*overall p-value= 0.00516 (between cases & controls)
**EM Frequency: Estimation Maximisation algorithm.
[0049] A significant increase of the G allele of the G(-200)T polymorphism in
an
schizophrenia (SCZ) case-control sample; this and the SCZ triad sample
combined
show association of the G allele with the disease. This result was not
replicated in the
schizophrenia triad sample alone. However, of the two groups, the case control
one is
CA 02517218 2005-08-25
14
by far the largest. Therefore, the lack of replication in the triad sample
could be due to
lack of power or to the inherent differences between the two sampling methods,
such
as bias towards earlier age at onset in triad design.
[0050] The 3'UTR marker T5988C was associated with bipolar (BP) disorder in
the
BP triad sample, whereas the A5806C marker showed positive association with
those
among the bipolar patients who had psychotic symptoms. The haplotype analyses
also
showed preferential transmission of haplotype G-C-T in SCZ whereas haplotype T-
CC was found to be protective in a SCZ case control sample but associated with
bipolar disorder in a BP sample. The analysis of the case control sample
showed
to marked differences between cases and controls in the overall haplotype
frequencies in
schizophrenia.
[0051] The 5'UTR thus appears to be associated with schizophrenia, whereas the
3'UTR is associated with psychosis, mood disorder, or a combination thereof.
[0052] The 5' UTR/SCZ association support a role of the promoter region of
GRIN2B
15 in the pathophysiology of SCZ. In addition, the present work and results
have
identified a different region of the same gene as playing a role in bipolar
disorder.
This suggests that the two disorders may share some elements of etiology or
pathophysiology.
[0053] Refining the phenotype, including examination of symptom clusters (such
as
2o psychotic symptoms or cognitive impairment), rather than diagnostic
classifications,
may provide further results.
[0054] All citations are hereby incorporated by reference.
25 [0055] Akbarian, S., N. J. Sucher, et al. (1996). "Selective alterations in
gene
expression for NMDA receptor subunits in prefrontal cortex of schizophrenics."
J
Neurosci 16(1): 19-30.
CA 02517218 2005-08-25
[0056] Benes, F. M., M. S. Todtenkopf, et al. (2001). "GluR5,6,7 subunit
immunoreactivity on apical pyramidal cell dendrites in hippocampus of
schizophrenics and manic depressives." Hippocampus 11(5): 482-91.
[0057] Chiu, H. J., Y. C. Wang, et al. (2003). "Association analysis of the
genetic
5 variants of the N-methyl D-aspartate receptor subunit 2b (NR2b) and
treatment-
refractory schizophrenia in the Chinese." Neuropsychobiology 47(4): 178-81.
[0058] Di Maria, E., Gulli, R., et al (2004) "Variations in the NMDA Receptor
subunit 2B Gene (GRIN2B) and Schizophrenia: A Case-Control Study". American
Journal of Medical Genetics Part B (Neuropsychiatric Genetics) 128B:27-29.
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IS
[0071] The present invention has been described with regard to one or more
embodiments. However, it will be apparent to persons skilled in the art that a
number
of variations and modifications can be made without departing from the scope
of the
2o invention as defined in the claims.
CA 02517218 2005-08-25
SEQUENCE LISTING
(1) GENERAL INFORMATION:
(i) APPLICANT:
(A) NAME: Centre for Addiction and Mental Health
(B) STREET: 250 College St. R-30
(C) CITY: Toronto
(D) STATE: Ontario
(E) COUNTRY: Canada
(F) POSTAL CODE (ZIP): M5T 1R8
(ii) TITLE OF INVENTION: Marker for Psychosis or Mood Disorder
(iii) NUMBER OF SEQUENCES: 6
(iv) COMPUTER READABLE FORM:
(A) MEDIUM TYPE: Floppy disk
(B) COMPUTER: IBM PC compatible
(C) OPERATING SYSTEM: PC-DOS/MS-DOS
(D) SOFTWARE: PatentIn Release #1.0, Version #1.30 (EPO)
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1
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2
CA 02517218 2005-08-25
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ACCCTCATCC CTGGAGTTTT ATACA 25
3
