2008 Barcelona - European Society of Human Genetics
2008 Barcelona - European Society of Human Genetics
2008 Barcelona - European Society of Human Genetics
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Clinical genetics<br />
frequency <strong>of</strong> this mutation averaged about 7% <strong>of</strong> all investigated chromosomes<br />
and 71% <strong>of</strong> chromosomes with mutations in GDAP1 gene .<br />
Analysis <strong>of</strong> the GDAP1 locus for markers D8S279-D8S1776-D8S286-<br />
D8S551-D8S548-D8S1805-D8S1705-D8S1757 demonstrated a common<br />
haplotype for markers D8S286; D8S551, D8S548, and D8S1805<br />
on the chromosomes with c .715C>T mutation . The association <strong>of</strong> the<br />
mutation with a common haplotype suggested a common ancestor .<br />
The date <strong>of</strong> diffusion <strong>of</strong> the mutation has been calculated by linkage<br />
disequilibrium between disease locus and these polymorphic markers .<br />
The “age” <strong>of</strong> mutation c .715C>T in Russian was approximately 1000<br />
years .<br />
P01.235<br />
investigation <strong>of</strong> GDAP1 Gene in iranian cmt Patients<br />
A. Abbasi 1 , M. Sadeghizadeh 1 , O. Ariani 2 , H. Tonekaboni 3 , M. H. Sanati 4 , M.<br />
Houshmand 4 ;<br />
1 Department <strong>of</strong> Biology, Tarbiat Modares University, Tehran, Islamic Republic<br />
<strong>of</strong> Iran, 2 Special Medical Center, Tehran, Islamic Republic <strong>of</strong> Iran, 3 M<strong>of</strong>id Hospital,<br />
Shahid Beheshti University <strong>of</strong> Medical Siences, Tehran, Islamic Republic<br />
<strong>of</strong> Iran, 4 National Institute for Genetic Engineering and Biotechnology, Tehran,<br />
Islamic Republic <strong>of</strong> Iran.<br />
Charcot-Marie-Tooth disease (CMT) is the most frequently occurring<br />
inherited peripheral neuropathy, affecting 1 in 2,500 . The disease is<br />
characterized by distal muscle weakness and atrophy, predominantly<br />
involving the legs . CMT disease caused by mutations in the gangliosideinduced<br />
differentiation-associated protein 1 (GDAP1) gene is a<br />
severe autosomal recessive neuropathy originally reported in families<br />
with either demyelinating CMT4A neuropathy or axonal neuropathy<br />
with vocal cord paresis which maps to the CMT4A locus on chromosome<br />
8q21 .1 . GDAP1 is a 358 amino acid protein which expressed<br />
in both the central and peripheral nervous system . 22 Iranian families<br />
with a diagnosis <strong>of</strong> CMT disease, either axonal or demyelinating, were<br />
available for genetic analysis <strong>of</strong> GDAP1 . Total genomic DNA was extracted<br />
from all family members using standard procedure . In all cases<br />
linkage analysis with different markers for the PMP22, MPZ, and GJB1<br />
genes were used to exclude mentioned gens involving . In the 8 remaining<br />
families genotyping for the 3 microsatellite markers linked to the<br />
CMT4A locus was performed using different PCR protocols for each<br />
marker (D8S164, D8S286, and D8S551) . PCR products were run on<br />
a 12% non denaturing polyacrylamide gel and allele fragments were<br />
visualised by silver staining . Our results showed the usefulness <strong>of</strong> linkage<br />
studies in diagnosis <strong>of</strong> CMT patients.We could identify and confirm<br />
CMT4A in 4 patients with use <strong>of</strong> these markers . The data in this study<br />
could also be used in prenatal diagnosis and carrier detection .<br />
P01.236<br />
control population distribution and in silico functional analysis<br />
<strong>of</strong> novel genetic variants in charcot-marie-tooth-Desease<br />
patients<br />
C. Concheiro Alvarez 1 , P. Blanco-Arias 1,2 , M. Zennaro 1 , M. Sobrido 3,2 , A. Carracedo<br />
1,3,2 ;<br />
1 Grupo de Medicina Xenómica-USC, Santiago de Compostela, Spain, 2 Centro<br />
de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Santiago<br />
de Compostela, Spain, 3 Fundación Pública Galega de Medicina Xenómica,<br />
Santiago de Compostela, Spain.<br />
When a variation (uncertain variant, UV) is found in a disease candidate<br />
gene, it is critical to establish whether this change is neutral or responsible<br />
for the observed disorder . As a result <strong>of</strong> sequence mutation screening<br />
<strong>of</strong> PMP22, MPZ, GDAP1, GJB1, EGR2, NEFL and LITAF in a group <strong>of</strong><br />
47 Spanish patients with a clinical diagnosis <strong>of</strong> Charcot-Marie-Tooth disease<br />
we found three non-synonymous, four synonymous and five intronic<br />
nucleotide substitutions not contained in dbSNP . In order to assess the<br />
possible pathogenic role <strong>of</strong> these 12 UVs, two approaches were used:<br />
1) Screening <strong>of</strong> 296 Caucasian controls, 200 <strong>of</strong> which are Galician individuals<br />
without any neurological disorder .<br />
2) In silico analysis to explore:<br />
• conservation across animal species (UCSC Genome Browser)<br />
• the impact <strong>of</strong> an amino acid substitution on the structure and function <strong>of</strong><br />
a human protein (Polyphen)<br />
• a potential role as a exonic splicing enhancer (ESEfinder)<br />
We present this strategy as a valuable mean to select the UVs most likely<br />
to have a biological function warranting further study by experimental<br />
models .<br />
P01.237<br />
Rapid diagnosis <strong>of</strong> CMTIA Deletion/duplication by real-time<br />
quantitative polymerase chain reaction<br />
S. Zare 1 , S. Akbari 1 , M. Karimipour 1,2 , M. Akbari 1,3 ;<br />
1 Tehran Medical <strong>Genetics</strong> Labratory, Tehran, Islamic Republic <strong>of</strong> Iran, 2 Molecular<br />
Medicine Dept.Biotechnology Research Center, Pasteur Institute<br />
<strong>of</strong> Iran,Tehran, Tehran, Islamic Republic <strong>of</strong> Iran, 3 Department <strong>of</strong> Medical<br />
<strong>Genetics</strong>,Tarbiat Modares University, Tehran, Islamic Republic <strong>of</strong> Iran.<br />
Charcot-Marie-Tooth disease (CMT) is the most common form <strong>of</strong> hereditary<br />
motor and sensory neuropathy (HMSN) . CMT has been classified<br />
into demyelinating (CMT1) and axonal (CMT2) forms.<br />
Around 70% <strong>of</strong> CMTIA cases are caused by a dominantly inherited<br />
1 .5 Mb duplication at 17p11 .2-12 encompassing the peripheral Myelin<br />
protein 22 (PMP22) gene . In contrast, hereditary neuropathy with liability<br />
to pressure palsies (HNPP) is caused by reciprocal deletion <strong>of</strong><br />
the same 1 .5 Mb region . In the present study, we developed a highly<br />
sensitive and specific quantitative gene dosage method for detecting<br />
the PMP22 duplication and deletion using Real time PCR .Real time<br />
quantitative PCR is a sensitive, specific and reproducible method for<br />
diagnosing PMP22 duplication and deletion . The method is fast, and<br />
requires no post-PCR handling .<br />
P01.238<br />
molecular diagnosis <strong>of</strong> cmt1A and HNPP using multiplex<br />
Ligation-dependent Probe Amplification (MLPA): Comparison<br />
with the PFGE-southern blot analysis<br />
H. Choung;<br />
Samsung medical center, Seoul, Republic <strong>of</strong> Korea.<br />
Background: Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary<br />
neuropathy with liability to pressure palsies (HNPP) are the<br />
two most common peripheral neuropathies caused by a duplication or<br />
deletion <strong>of</strong> the 1 .5-Mb region containing PMP22 gene on 17p11 .2, respectively.<br />
Although pulsed-field gel electrophoresis (PFGE)-Southern<br />
blot (SB) analysis is considered as the reference method for molecular<br />
diagnosis <strong>of</strong> CMT1A/HNPP, several methods such as fluorescence insitu<br />
hybridization (FISH), short tandem repeat (STR) analysis, multiplex<br />
fluorescence PCR, and real-time PCR have been tried to avoid<br />
laborious and time-consuming PFGE-SB method .<br />
Methods: We tried to evaluate newly developed multiplex ligation-mediated<br />
probe amplification (MLPA) method for the detection <strong>of</strong> the specific<br />
1.5-Mb duplication/deletion by prospectively testing 31 patients<br />
referred for differential diagnoses <strong>of</strong> CMT1A or HNPP . MLPA probemixes<br />
contain TEKT3, PMP22, FLJ25830, BX089850 and COX10<br />
genes within the CMT1A/HNPP region . The results with MLPA method<br />
were compared with our current PFGE-SB method .<br />
Results: Thirteen out <strong>of</strong> 31 patients were diagnosed as having either<br />
duplication (n=3) or deletion (n=9) by PFGE-SB method and all the<br />
results were concordant with those by MLPA analysis . The turnaround<br />
time (TAT) by MLPA is estimated to be 4 days while TAT by PFGE-SB<br />
is approximately 17 days .<br />
Conclusions: MLPA is a sensitive and specific technique for the detection<br />
<strong>of</strong> duplication or deletion <strong>of</strong> PMP22 gene and its turnaround time is<br />
much shorter than the PFGE-Southern blotting . Therefore, MLPA could<br />
be a good alternative method replacing laborious PFGE-SB analysis .<br />
P01.239<br />
subependymal heterotopia in the severe variant subtype <strong>of</strong><br />
Adams-Oliver syndrome<br />
B. Dallapiccola1,2 , F. Brancati1 , R. Mingarelli1 ;<br />
1 2 IRCCS CSS Mendel Institute, Rome, Italy, Department <strong>of</strong> Experimental Medicine<br />
and Pathology, La Sapienza Univerity, Rome, Italy.<br />
We recently ascertained a 7-year-old female born from non-consanguineous<br />
healthy parents with left talipes equinovarus, bilaterally absent/severely<br />
hypoplastic/malformed toes with absence <strong>of</strong> nails . Her<br />
psychomotor development was severely delayed and she suffered <strong>of</strong><br />
seizures since the age <strong>of</strong> 3 years . At the time <strong>of</strong> examination (aged 13<br />
years) she shows bilateral transverse reduction <strong>of</strong> digits, prominent<br />
veins over the trunk with rare café-au-lait spots and severe mental<br />
retardation with aggressive behaviour . Brain magnetic resonance scan<br />
shows bilateral nodular foci <strong>of</strong> tissue in the subependymal region lining<br />
the lateral ventricles . A focal area <strong>of</strong> irregular cortical surface is also<br />
present, suggesting cortical dysplasia .<br />
This girl fits the diagnosis <strong>of</strong> Adams-Oliver syndrome (AOS) and cor-<br />
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