2008 Barcelona - European Society of Human Genetics

Therapy for genetic disease
The diet of a child with a CL/P is critical for growth and development
besides adequate gain in weight, which is important to corrective
surgery at the right time . Despite of the high prevalence and the importance
of nutritional intake, there are around 50 articles involving
nutritional approaches over 50 years . We present a proposal of an
algorithm for multiprofessional intervention for nutrition of CL/P babies
before surgery .
P10.08
mechanism of cmt1A phenotypic correction by high dose of
ascorbic acid
S. Belin 1 , F. Kaya 1 , G. Diamantidis 2 , M. Fontes 1 ;
1 INSERM, Marseille, France, 2 University, Thessaloniki, Greece.
Charcot-Marie-Tooth [CMT] syndrome is the most common hereditary
peripheral neuropathy usually results from triploidy of the PMP22
gene . Preclinical trials using an animal model show that disabled mice
force-fed with high doses of ascorbic acid partially recover muscular
strength after a few months of treatment, and suggest that high doses
of ascorbic acid repress PMP22 expression (Passage et al, Nature
medicine, 2004) .
PMP22 gene expression was under the control of cAMP stimulation
(Saberan et al, Gene, 2000) . Recently we demonstrated that ascorbic
acid represses PMP22 gene expression by acting on intracellular
cAMP levels and adenylate cyclase activity . This action is dose-dependent
and specific to ascorbic acid, since repression is not observed
after treatment with other antioxidants (Kaya et al, Neuromuscular
Disord, 2007) . Indeed we showed that ascorbic acid is a competitive
inhibitor of cyclase adenylate enzyme . This work enabled us to propose
an unsuspected mechanism of action explaining the phenotype
correction, and to identify two new potential therapeutic targets: the
ascorbic acid would act directly on the PMP22 gene expression by
decreasing intracellular cAMP concentration via the inhibition of the
adenylate cyclase activity .
P10.09
U1snRNA-mediated rescue of mRNA processing in severe factor
VII deficiency
F. Pagani1 , M. PInotti2 , F. Bernardi2 ;
1 2 ICGEB, Trieste, Italy, Department of Biochemistry and Molecular Biology,
University of Ferrara, Ferrara, Italy.
Small nuclear U1-RNAs (snRNAs), the spliceosome components selectively
recognizing donor splice sites (5’ss), were engineered to restore
correct mRNA processing in a cellular model of severe coagulation
factor VII (FVII) deficiency, caused by the IVS7 9726+5g/a change.
Three U1-snRNAs, complementary to the mutated 5’ss (U1+5a) or to
neighbouring sequences, were expressed with FVII minigenes in a
hepatoma cell line .
The U1-snRNAs reduced from 80% to 40% the exon 7 skipping, thus
increasing exon definition. The U1+5a construct also dramatically
increased recognition of the correct 5’ss over the 37bp-downstream
cryptic site preferentially activated by the mutation, thus inducing appreciable
synthesis of normal transcripts (from barely detectable to
50%) . This effect, which was dose-dependent, clearly demonstrated
that impaired recognition by the U1-snRNA was the mechanism responsible
for FVII deficiency. These findings suggest compensatory
U1-snRNAs as therapeutic tools in coagulation factor deficiencies
caused by mutations at 5’ss, a frequent cause of severe defects .
P10.10
Influence of proprioceptive training program in children with
Down syndrome
E. Sirbu 1 , B. Almajan-Guta 2 , V. Almajan-Guta 3 , D. Stoicanescu 4 ;
1 West University of Timişoara, Timisoara, Romania, 2 University Politehnica
Timisoara, Timisoara, Romania, 3 Speranta Special Care Center, Timisoara,
Romania, 4 University of Medicine &Pharmacy, Timisoara, Romania.
Background: In these days, Down syndrome comes again in the concern
of medical researchers because early intervention treatment can
improve the quality of life of these children . The goal of our study was
to prove the efficiency of a proprioceptive training program on the motor
development stages of children with Down syndrome .
Methods: The study was performed between September 2006 - September
2007 . The study was performed on 30 children from the “Speranta”
Special Care Center Timisoara (16 girls and 14 boys) with the
age range between 2 months and 5 years . The lot was divided in two
groups: control group (15 subjects) and experiment group (15 subjects)
. The study subjects underwent physiotherapy and physical exercise
and the experimental group followed a proprioceptive training
program . The intervention consisted of three sessions of 45 minutes
each, per week . The children were assessed before, during and after
this physical intervention using Bayley Motor Scales of Infant Development
.
Results: As the results indicated, the experimental group showed a
statistically significant improvement in all measured values when compared
with the control group .
Conclusion: The proprioceptive training was superior in the improvement
of the posture, of the transfers and of the balance, compared
to classical physical therapy . The delays in motor development milestones
were more severe in the study group compared to experimental
group .
P10.11
Antisense Oligomer (AO) induced exon skipping in the mdx 4cv
mouse model
C. Mitrpant, S. Fletcher, S. D. Wilton;
Australian Neuromuscular Research Institute (ANRI), Perth, Australia.
Duchenne muscular dystrophy (DMD), a relentless progressive muscular
dystrophy is caused by protein truncating mutations in the dystrophin
gene that result in the absence of functional dystrophin . Loss
of dystrophin leads to irreparable membrane damage, thus promoting
calcium ion influx and cell death.
Antisense Oligomer (AO) induced exon skipping is a molecular intervention
whereby AOs are targeted to motifs involving in pre-mRNA
splicing. This has been used to induce specific exon removal and
by-pass the disease-causing gene lesion in the mdx mouse model of
muscular dystrophy . We are investigating exon skipping in the B6Ros .
Cg-Dmd mdx-4Cv /J (mdx 4 CV ) muscular dystrophy mouse, which carries
a nonsense mutation in exon 53 of the dystrophin gene . To restore
the reading frame, both exons 52 and 53 must be excised from the
mature dystrophin gene transcript to by-pass the primary gene lesion
and maintain the reading frame . 2’-O-Methyl AOs, on a phosphorothioate
backbone have been designed to mask these exons from the
splicing machinery and lead to their excision . Initial AO combinations
induced skipping of exons 52/53 and restored some protein expression
. However the predominant transcript was missing only exon 53 as
determined by RNA studies . We designed additional AOs to enhance
exon skipping of both exons 52 and 53 .
We highlight the importance of AO design to enhance efficiency of
single and multi-exon removal .
P10.12
study on the chaperone effect of several iminosugars and
aminocyclitols on mutated glucocerebrosidases as a treatment
for Gaucher disease
G. Sanchez-Olle 1,2,3 , M. Egido-Gabas 4 , J. Duque 5 , A. Yudego 5 , J. Casas 4 , A.
Chabas 5,3 , D. Grinberg 1,2,3 , L. Vilageliu 1,2,3 ;
1 Universitat de Barcelona, Barcelona, Spain, 2 IBUB, Barcelona, Spain, 3 CIBER-
ER, Barcelona, Spain, 4 RUBAM, Departament de Química Orgànica Biològica,
IIQAB-CSIC, Barcelona, Spain, 5 Institut de Bioquímica Clínica, Barcelona,
Spain.
Gaucher disease is an autosomal recessive disorder, characterized by
the accumulation of glucosylceramide in lysosomes, because of acid
β-glucosidase deficiency. Some competitive inhibitors, at subinhibitory
concentrations, can work as chemical chaperones . We have tested
the effect of two iminosugars, N-(n-nonyl)-deoxynojirimycin (NN-DNJ)
and N-(n-butyl)-deoxynojirimycin (NB-DNJ), and four aminocyclitols on
stable transfected COS-7 cells and patient fibroblasts.
In stable cell lines, NN-DNJ led to a 1 .2 to 1 .4-fold increase in the activity
of G377S, N188S and wild-type GBAs at different concentrations .
A slight increase was noticed in the activity of the N188S;E326K GBA
at 2.5 μM. NB-DNJ at 5 μM induced a 1.2-fold increase in the GBA
activity of COS-7 cells transfected with the N188S and N188S;E326K
cDNAs . A slight increase was also observed in cells transfected with
the wild-type cDNA . The aminocyclitol C4 Ph showed a 1 .2 to 1 .4-fold
increase on wild-type and N188S GBAs, at different concentrations . At
15 μM, 1.2-fold increase for N188S;E326K GBA was also observed.
In fibroblasts, treatment with NN-DNJ produced an increase of activity