European Human Genetics Conference 2007 June 16 – 19, 2007 ...

Therapy for genetic disease
P1401. Enzyme replacement therapy in 4 patients with
mucopolysaccharidoses type-6
S. Başaran Yılmaz, E. Karaca, B. Tüysüz;
Istanbul University, Cerrahpasa Medical School, Medical Genetics, İstanbul,
Turkey.
The mucopolysaccharidoses (MPS) are a heterogeneous group of
lysosomal storage disorders caused by the deficiency of enzymes involved
in degradation of glycosaminoglycans. Mucopolysaccharidosis
type-6 is characterised by osseous, corneal and visceral changes without
intelligence impairment.
We started to enzyme replacement therapy in four patients with MPS
type-6 on November 2006 with Naglazyme (Galsulfase). Our patients
are a girl-7.5 years old and 3 boys-3.5, 6 and 9 years old. All patients
have coarse facies, joint stiffness, corneal clouding, hearing loss, valvular
heart dissease, dysostosis multiplex, hepatosplenomegaly and
normal intelligence. One patient has also glaucoma, and one has adenoid
vegetation.
These patients were diagnosed clinically and definitive diagnosis were
made by enzyme analyses. Deficiency of Arylsulphatase B enzyme
was found in all patients.
We assayed the patients with clinical examination,vital signs, 6 minutes
walking test, echocardiography, measures of joint ranges, pulmonary
function tests, ophtalmologic and hearing examinations before
the therapy.
All patients received weekly intravenous infusions with 1 mg/kg Galsulfase.
Because of the potentiallity of infusion reactions patients received
antihistamines and antipyretics before the infusions. They hadn’t any
complication except two patient had vomits for two times.We aimed to
treat the somatic symptoms of patients. When 3 months of the therapy
were completed we reassay the patients clinically. Their complaints
about sleep apnea and difficulties of daily activities were reduced.
P1402. Multi-exon skipping removing exons 45 through 55 of the
DMD transcript could rescue up to 63% of Duchenne Muscular
Dystrophy patients
C. Béroud 1,2 , S. Tuffery-Giraud 1,3 , M. Matsuo 4 , D. Hamroun 1,2 , V. Humbertclaude
1,2 , N. Monnier 5,6 , M. Moizard 7 , M. Voelckel 8 , L. Michel Calemard 9 , P.
Boisseau 10,11 , M. Blayau 12 , C. Philippe 13 , M. Cossée 14 , M. Pagès 15 , F. Rivier 16 , O.
Danos 17 , L. Garcia 17 , M. Claustres 1,2 ;
1 INSERM U 827, Montpellier, France, 2 CHU Montpellier, Hôpital Arnaud de Villeneuve,
Laboratoire de Génétique Moléculaire, Montpellier, France, 3 Université
Montpellier 1, UFR Médecine, Montpellier, France, 4 Department of Pediatrics,
Kobe University Graduate School of Medicine, Kobe, Japan, 5 Laboratoire de
Biochimie Génétique et Moleculaire, CHU de Grenoble, Grenoble, France,
6 INSERM U607, Grenoble, France, 7 INSERM U 619, CHU Bretonneau, Tours,
France, 8 Laboratoire de Génétique Moléculaire, Département de Génétique
Médicale, Hôpital d’Enfants de la Timone, Marseille, France, 9 Laboratoire de
Biochimie, Hôpital Debrousse, Lyon, France, 10 INSERM U 533, Nantes, France,
11 Université de Nantes, Nantes, France, 12 Laboratoire de Génétique Moléculaire,
Rennes, France, 13 Laboratoire de Génétique, EA 3441, CHU Brabois,
Vandoeuvre-les-Nancy, France, 14 Laboratoire de Diagnostic Génétique, Hôpitaux
Universitaires de Strasbourg et Faculté de Médecine, Strasbourg, France,
15 Département de Neurologie, CHU de Montpellier, Montpellier, France, 16 Service
de Neuropédiatrie, CHU de Montpellier, Montpellier, France, 17 Genethon &
CNRS UMR 8115, Evry, France.
To collect and analyze mutation information, we developed a generic
software called Universal Mutation Databases (UMD). This software
includes a large set of analysis tools primarily created for molecular
epidemiology studies and subsequently to address more complex topics
such as genotype-phenotype correlations. With the development of
innovative therapies for patients suffering from rare genetic diseases,
it appeared that bioinformatics and LSDBs could play an important
role.
Thus, we created specific routines to help researchers to design
therapeutic strategies such as exon skipping whose archetype is the
DMD gene associated with Duchenne (DMD) and Becker dystrophies
(BMD).
Approximately two-third of DMD patients show intragenic deletions
from one to several exons of the DMD gene leading to a premature
stop codon. Other deletions that maintain the translational reading
frame result in BMD. The opportunity to transform a DMD phenotype
into a BMD phenotype appeared as a treatment strategy with the de-
velopment of various technologies, which are able to induce an exon
skipping at the pre-mRNA level in order to restore an open reading
frame. Because the DMD gene contains 79 exons, thousands of potential
transcripts could be produced by exon skipping and should be
investigated.
By using UMD algorithms, we predicted that an optimal multi-exon
skipping leading to the del45-55 artificial dystrophin (c.6439_8217del)
could transform DMD phenotype into asymptomatic or mild BMD phenotype.
This multiple-exon skipping could theoretically rescue up to
63% of DMD patients with a deletion while the optimal mono-skipping
of exon 51 would rescue only 16% of patients.
P1403. Recovery of female Fanconi anemia fertility after
chemotherapy, irradiation and bone marrow allograft/further
evidence against oocyte regeneration by bone arrow-derived
germline stem cells
M. S. Fellous1 , V. Reiner1 , G. Eliane2 , S. Jean2 ;
1 2 Institut Cochin FDPM,, Paris, France, Hopital Saint Louis, Service de greffe
de Moelle Osseuse, Paris, France.
Mammalian oocytes are formed before or shortly after birth. However,
recent controversial papers cast doubts on this paradigm by claiming
that new ovarian follicles can be generated in the mouse by germline
stem cells (GSCs) supplied by the bone marrow (BM). Here we consider
an issue related to the potential existence of GCSs : the genetic
origin of offspring after allogeneic hematopoietic stem cell transplantation
in humans. To clarify this issue, we have examined a rare clinical
situation in which a woman with Fanconi Anemia (FA) gave birth to
a child after allogeneic BM transplantation. We have genotyped the
mother (patient), the daughter, and the donor; several informative polymorphic
microsatellites demonstrated the genetic relationship between
the other and the daughter. The rare clinical situation described here is
reminiscent of the observations described in the controversial papers.
However, it leads to an alternative explanation. Our data show that
recovery of fertility after BM transplantation can result from incomplete
depletion of the ovarian follicular pool and not from its replacement by
donor BM-derived GSCs.
P1404. The pharmacological chaperone AT1001 increases levels
of mutant alpha-galactosidase A in Fabry patient cell lines and
reduces GL-3 levels in a mouse model of Fabry disease
E. R. Benjamin1 , R. Khanna1 , H. H. Chang1 , R. Soska1 , A. Schilling1 , C. Pine1 ,
B. A. Wustman1 , R. J. Desnick2 , D. J. Lockhart1 , K. J. Valenzano1 ;
1 2 Amicus Therapeutics, Cranbury, NJ, United States, Mount Sinai School of
Medicine, New York, NY, United States.
Fabry disease is an X-linked lysosomal storage disorder caused by deficient
α-galactosidase A (GLA) activity and accumulation of globotriosylceramide
(GL-3) and related glycolipids. Over 400 Fabry mutations
have been reported; ~60% are missense. Previously, the pharmacological
chaperone, AT1001 (migalastat hydrochloride), was shown to
increase R301Q GLA activity in vitro and in vivo. To evaluate the response
of other Fabry GLA mutations, male patient lymphoid cell lines
representing more than 50 different missense mutations were incubated
with AT1001 (5 nM to 1 mM) for 5 days, and effects on GLA activity
were determined. Basal enzyme activity ranged from 0% to 35% of
wild type (WT). Significantly increased GLA activity was observed in
over 34 cell lines (1.5- to 20-fold; post-treatment GLA activities ranged
from 2.4% to 110% WT), with varying EC values: from 600 nM to
50
>1 mM. Next, the effect of AT1001 was tested in GLA knockout mice
that express a human R301Q transgene (R301Q Tg/KO). Daily oral
gavage of AT1001 (30 mg/kg PO; 4 weeks) to male R301Q Tg/KO
mice resulted in significantly increased GLA activity (p