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2009 Vienna - European Society of Human Genetics

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Molecular and biochemical basis <strong>of</strong> disease<br />

splice change that produces the skipping <strong>of</strong> exon 25.<br />

This strategy allows 1) straightforward and rapid analysis <strong>of</strong> the whole<br />

DMD gene, 2) the detection <strong>of</strong> virtually all mutations, 3) further understanding<br />

<strong>of</strong> the molecular effect <strong>of</strong> such changes.<br />

P16.45<br />

mutation Analysis <strong>of</strong> Limb Girdle muscular Dystrophy in the<br />

czech Republic<br />

K. Stehlikova 1 , M. Hermanova 2 , P. Vondracek 3 , L. Fajkusova 1 ;<br />

1 University Hospital, Centre <strong>of</strong> Molecular Biology and Gene Therapy, Brno,<br />

Czech Republic, 2 University Hospital, Department <strong>of</strong> Pathology, Brno, Czech<br />

Republic, 3 University Hospital, Department <strong>of</strong> Paediatric Neurology, Brno,<br />

Czech Republic.<br />

Limb girdle muscular dystrophy type 2A (LGMD2A) is an autosomal<br />

recessive disorder characterized by atrophy and weakness <strong>of</strong> proximal<br />

girdle muscles. LGMD2A is caused by mutations in the CAPN3 gene<br />

(15q15) that encodes the muscle specific protein, calpain-3 (p94). LG-<br />

MD2A is the most frequent form <strong>of</strong> LGMD in many <strong>European</strong> countries.<br />

Until now, more than 300 pathogenic mutations have been found in the<br />

CAPN3 gene. We performed analysis <strong>of</strong> the CAPN3 gene in LGMD2A<br />

patients at both the mRNA level using reverse transcription-PCR or at<br />

the DNA level using PCR and direct sequencing. We screened 138<br />

unrelated patients with preliminary diagnoses <strong>of</strong> limb girdle muscular<br />

dystrophy for mutations in the CAPN3 gene. 39 patients (28%) were<br />

found to carry mutations in the CAPN3 gene. We detected 16 previously<br />

reported mutations and 3 novel mutations (c. 802_945del, c.<br />

1783_1788del, p.Q619X).<br />

Our results show that mutation 550 delA is the most frequent CAPN3<br />

defect in Czech LGMD2A patients (53 %). In total, 33 % <strong>of</strong> the patients<br />

with mutation in the CAPN3 gene are homozygous for c.550delA, and<br />

64 % carry it at least on one allele. Other frequent mutation is 598_<br />

612del (11%), both mutations are localised in the 4. exon.<br />

This work was supported by grant MSMT LC06023.<br />

P16.46<br />

cAPN3 mutations in Russian patients with limb-girdle muscular<br />

dystrophy, type 2A<br />

O. Ryzhkova, G. Rudenskaya, E. Dadaly, O. Schagina, A. Polyakov;<br />

Research Center for Medical <strong>Genetics</strong>, Moscow, Russian Federation.<br />

Limb-girdle muscular dystrophy, type 2A (LGMD2A, MIM 253600) is<br />

considered the most frequent autosomal recessive MD almost everywhere<br />

in the world. The causative gene is CAPN3 located in chromosomal<br />

region 15q15.1-q21.1 and encoding a muscle-specific protease,<br />

calpain 3. Common mutations are collected mostly in eight <strong>of</strong> CAPN3<br />

24 exons, namely, exons 4, 5, 10, 11,12, 20, 21, and 22. Forty-two<br />

unrelated Russian patients with clinical presentation <strong>of</strong> LGMD were<br />

screened for common CAPN3 mutations by direct sequencing <strong>of</strong><br />

the eight exons. In 17 patients (40.5%), seven already known mutations<br />

were detected: c.550delA, c.598-612del, c.649G>A, c.706G>A,<br />

c.1250C>T, c.2243G>A, and c.2305C>T. In 10 patients, mutations only<br />

in one allele were identified which points to a significant proportion <strong>of</strong><br />

infrequent CAPN3 mutations. Mutation c.550delA was found in 13 <strong>of</strong><br />

17 patients (76.5%) in homozygous (3 cases), compound heterozygous<br />

(3) or heterozygous (7) state, thereby in 44.4% (16/34) <strong>of</strong> affected<br />

alleles. Thus, in Russia, c.550delA is the most common CAPN3<br />

mutation, as well as in Bulgaria, Croatia, Slovenia, and North Italy.<br />

Other six mutations were detected in single patients and not in homozygous<br />

state. Of 17 patients, 16 were <strong>of</strong> Slavic (Russian, Ukrainian,<br />

Byelorussian) and one <strong>of</strong> Korean ethnicity; only one case was familial.<br />

All patients showed typical involvement <strong>of</strong> pelvic and shoulder girdle<br />

muscles, with no cardiomyopathy, and with calf hypertrophy in some.<br />

Age <strong>of</strong> onset varied greatly (from 3 to 34 years) as well as the disease<br />

progression. Serum creatine kinase level was also highly variable,<br />

350—9800 U/l.<br />

P16.47<br />

A novel mutation in the Ryanodine-Receptor Gene (RYR1) in<br />

malignant Hyperthermia: case report<br />

N. Pronina 1,2 , T. Kaulins 3,4 , M. Mihelsons 5 , O. Osipova 1 , O. Sterna 1 , R. Lugovska<br />

1 ;<br />

1 Children’s University Hospital, Riga, Latvia, 2 Riga Stradins University, Riga,<br />

Latvia, 3 Latvian Maritime Medicine centre, Riga, Latvia, 4 University <strong>of</strong> Latvia,<br />

Latvia, 5 University <strong>of</strong> Latvia, Riga, Latvia.<br />

Malignant hyperthermia (MH) is an autosomal dominant, life-threatening<br />

pharmacogenetic disorder that is one <strong>of</strong> the causes <strong>of</strong> death<br />

during anesthesia with volatile anesthetic agents and succinylcholine<br />

and in the early postoperative period. The disease is genetically heterogeneous,<br />

with mutations in the ryanodine receptor gene (RYR1) at<br />

19q13.1 accounting for up to 80% <strong>of</strong> the cases. To treat developed MH<br />

Dantrolene is used.<br />

A 57 y.o. male patient underwent thyreoidectomia in 2003 in State<br />

Hospital in Riga and developed following symptoms: EtCO 2 max 80<br />

mmHg, HR till 150 beats/min, T 40,8ºC, CPK 1616 U/l after anaesthesia<br />

with sev<strong>of</strong>lurane, fentanyl and succinylholine. Dantrolene was not<br />

available in Latvia and patient died in 5 hours after anaesthesia. According<br />

to EMHG guidelines in vitro contracture test (IVCT) and DNA<br />

analysis were performed for the MHs patient’s relatives.<br />

IVCT revealed positive results with halothane and caffeine for two<br />

<strong>of</strong> MH-like patient’s family members. The functional investigation <strong>of</strong><br />

RYR1 function in ex vivo tissues discovered the significant statistical<br />

difference in rest Ca 2+ concentrations in MHs and MHn myotubes was<br />

found. The half-maximal action’s concentration with 4CmC was significantly<br />

lower in comparison with control group (p= 0.002).<br />

Novel mutation G528T in gene RYR1 was found for four family members.<br />

Mutation G528T is a missense mutation that affects the ryanodine<br />

receptor type1 protein structure.<br />

We consider that this novel mutation the G528T should be included<br />

in MH causative RYR1 Mutations list, though the EMHG guidelines<br />

reclaim the necessity to find the same mutation in other unrelated family.<br />

P16.48<br />

Alteration <strong>of</strong> expression <strong>of</strong> muscle-specific is<strong>of</strong>orms <strong>of</strong> FXR1P in<br />

facio scapulohumeral muscular distrophy patients<br />

B. Bardoni 1 , S. Sacconi 2 , L. Davidovic 1 ;<br />

1 Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France, 2 Centre<br />

de Référence pour les Maladies Neuromusculaires, CHU de Nice, Nice,<br />

France.<br />

The Fragile X Mental Retardation-Related 1 (FXR1) gene belongs to<br />

the Fragile X Related family, that also include the Fragile X Mental retardation<br />

(FMR1) gene involved in Fragile X syndrome, the most common<br />

form <strong>of</strong> inherited mental retardation. While the absence <strong>of</strong> FMRP<br />

impairs cognitive functions, inactivation <strong>of</strong> FXR1 has been reported to<br />

have drastic effects in mouse and xenopus myogenesis. Seven alternatively<br />

spliced FXR1 mRNA variants have been identified, three <strong>of</strong> them<br />

being muscle-specific. Interestingly, they encode FXR1P is<strong>of</strong>orms displaying<br />

selective RNA-binding properties. Since FacioScapuloHumeral<br />

muscular Dystrophy (FSHD) is an inherited myopathy characterized<br />

by altered splicing <strong>of</strong> mRNAs encoding muscle-specific proteins, we<br />

have studied the splicing pattern <strong>of</strong> FXR1 mRNA in myoblasts and<br />

myotubes <strong>of</strong> FSHD patients. We show here that FSHD myoblasts display<br />

an abnormal pattern <strong>of</strong> expression <strong>of</strong> FXR1P is<strong>of</strong>orms. Moreover,<br />

we provide evidence that this altered pattern <strong>of</strong> expression is due to<br />

a specific reduced stability <strong>of</strong> muscle-specific FXR1 mRNA variants,<br />

leading to a reduced expression <strong>of</strong> FXR1P muscle-specific is<strong>of</strong>orms.<br />

Our data suggest that the molecular basis <strong>of</strong> FSHD not only involves<br />

splicing alterations, as previously proposed, but may also involve a<br />

deregulation <strong>of</strong> mRNA stability. In addition, since FXR1P is an RNAbinding<br />

protein likely to regulate the metabolism <strong>of</strong> muscle-specific<br />

mRNAs during myogenesis, its altered expression in FSHD myoblasts<br />

may contribute to the physiopathology <strong>of</strong> this disease.<br />

P16.49<br />

molecular diagnostics <strong>of</strong> DmD gene in Polish patient with<br />

Duchenne/Becker muscular dystrophy<br />

M. Kaczmarek 1 , J. Hoppe-Gołębiewska 1 , A. Pławski 1 , N. Drwęska 2 , M. Szalata<br />

2,1 , J. Wigowska-Sowińska 3 , J. Pilch 4 , R. Słomski 2,1 ;<br />

1 Institut <strong>of</strong> <strong>Human</strong> <strong>Genetics</strong>, Poznan, Poland, 2 University <strong>of</strong> Life Sciences,<br />

Poznan, Poland, 3 Universty School <strong>of</strong> Medical Sciences, Poznan, Poland, 4 Silesian<br />

Academy <strong>of</strong> Medical Sciences, Katowice, Poland.<br />

Duchenne/Becker muscular dystrophy is lethal, recessive, X-linked<br />

disease, characterized by progressive muscular weakness and degeneration<br />

<strong>of</strong> skeletal muscles. It is caused by mutations within the<br />

dystrophin gene. Approximately 60% <strong>of</strong> DMD and BMD patients carry<br />

large deletions comprising even several exons. The remaining mu-

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