2009 Vienna - European Society of Human Genetics
2009 Vienna - European Society of Human Genetics
2009 Vienna - European Society of Human Genetics
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Molecular basis <strong>of</strong> Mendelian disorders<br />
patients, but no controls, and is under further investigation.<br />
Four patients carried de-novo WT1 mutations, 3 had previously characterized<br />
mutations (1 with IVS9+5G>A, and 2 with R394W,) and the<br />
fourth had a novel mutation R366H, predicted to be pathogenic in<br />
silico. Karyotype analysis showed XX in 3 patients, consistent with the<br />
female phenotype, but one (with R394W), was XY and had complete<br />
gonadal dysgenesis.<br />
Thus 7/19 sporadic SRNS patients, (but no familial cases) had NPHS2<br />
or WT1 mutations, indicating that molecular investigation <strong>of</strong> these<br />
genes is useful to support definitive diagnosis and management <strong>of</strong><br />
pediatric SRNS..<br />
P12.120<br />
Genotype-phenotype correlations in patients with hereditary<br />
neurodegenerative diseases<br />
N. V. Hryshchenko1 , E. I. Patscun2 , L. A. Livshits1 ;<br />
1 2 Institute <strong>of</strong> Molecular Biology and <strong>Genetics</strong>, Kiev, Ukraine, Regional Clinical<br />
Hospital, Uzhgorod, Ukraine.<br />
Neurodegenerative diseases (ND) are characterized by progressive<br />
nervous system (NS) dysfunction, associated with mutation in genes<br />
leads to atrophy <strong>of</strong> the affected central or peripheral NS structures.<br />
To summarize our experience in the field <strong>of</strong> neurogenetics we provide<br />
the investigation <strong>of</strong> mutations associated with various NS dysfunction<br />
in patients with Huntington’s disease (HD) and Charcot-Marie-Tooth<br />
(CMT) disease.<br />
HD is a common disorder <strong>of</strong> central NS caused by expansion <strong>of</strong> CAGrepeats<br />
in the IT15. CMT is a heterogeneous group <strong>of</strong> peripheral NS<br />
diseases with more than 20 involved loci. The most common types <strong>of</strong><br />
CMT are due to mutations in PMP22 and Cx32.<br />
Analysis <strong>of</strong> CAG-, CCG- and del2642 <strong>of</strong> IT15 gene polymorphisms<br />
has been performed in patients with HD. We have provided the<br />
screening <strong>of</strong> PMP22 duplications/deletion and Cx32 point mutations<br />
in CMT patients. 35 HD-probands had expanded allele <strong>of</strong> IT15 (39-<br />
52 CAG-repeats). The significant differences in sex-determined instability<br />
<strong>of</strong> CAG-repeats inheritance have been revealed. The association<br />
between del2642 and the age <strong>of</strong> HD onset has been analyzed.<br />
PMP22-duplications were found in 21 CMT-families. We also detected<br />
the heterozygote PMP22 gene deletion in two patients with specific<br />
HNPP-phenotype. Mutation screening <strong>of</strong> Cx32 revealed 2 brothers<br />
with Arg22Gln mutation.Our data showed the association between different<br />
types <strong>of</strong> IT15, PMP22 and Cx32 genes mutations and specific<br />
abnormalities <strong>of</strong> the NS. Obtained data would be useful for better understanding<br />
<strong>of</strong> ND pathogenesis and for providing new individualized<br />
therapy for curing <strong>of</strong> neurological disorders.<br />
P12.121<br />
Identification and characterization <strong>of</strong> mutations causing<br />
Niemann-Pick disease types A/B in spanish patients<br />
L. Rodríguez-Pascau 1 , L. Gort 2 , E. H. Schuchman 3 , A. Chabás 2 , L. Vilageliu 1 ,<br />
D. Grinberg 1 ;<br />
1 Departament de Genètica, Facultat de Biologia, Universitat de Barcelona,<br />
CIBERER, IBUB, Barcelona, Spain, 2 Institut de Bioquímica Clínica, Hospital<br />
Clínic, Corporació Sanitària Clínic, CIBERER, Barcelona, Spain, 3 Department<br />
<strong>of</strong> <strong>Genetics</strong> & Genomic Sciences, Mount Sinai School <strong>of</strong> Medicine, New York,<br />
NY, United States.<br />
Niemann-Pick disease type A/B (NPD A/B) is an autosomal recessive<br />
lysosomal storage disorder caused by acid sphingomyelinase (ASM)<br />
deficiency due to mutations in the SMPD1 gene. Type A NPD is the<br />
severe neurological form whereas type B NPD patients have no neurological<br />
manifestations. In this work, we present a molecular analysis <strong>of</strong><br />
19 Spanish patients and 2 from Maghreb, 8 with type A and 13 with type<br />
B NPD. All mutant SMPD1 alleles were identified, including 17 different<br />
mutations, 10 <strong>of</strong> which were novel: c.503G>A (p.W168X), c.939C>A<br />
(p.Y313X), c. 1100A>G (p.Y367C), c.1400A>C (p.Y467S), c.1445C>A<br />
(p.A482E), c.1456A>G (p.T486A), c.1159delC (p.R387VfsX7),<br />
c.1169_1171delTCT (p.F390del), c.1257+4_1257+7delAGGG, and<br />
c.1774_1776delACT (p.T592del). The only frequent mutations in the<br />
21 NPD patients were c.1823_1825delGCC (p.R608del) (38%) and<br />
c.1445C>A (p.A482E) (9%). For most <strong>of</strong> the mutations a good correlation<br />
between genotype and phenotype could be established and,<br />
in particular, the p.R608del-type B association was confirmed. Six <strong>of</strong><br />
the mutations found in Spanish patients, and two other mutations for<br />
comparison, were expressed in vitro to establish their residual enzy-<br />
matic activities. All mutant alleles were confirmed to be disease-causing<br />
due to their low enzyme activity, although western blot analyses<br />
showed that a normal amount <strong>of</strong> protein was synthesized. The mutation<br />
c.1257+4_1257+7delAGGG, which affects a non-canonical donor<br />
splice site, was analysed at the RNA level. Only aberrant mRNAs, corresponding<br />
to previously reported minor SMPD1 transcripts, which do<br />
not code for functional enzymes, were produced by this allele. This<br />
study is the first exhaustive mutational analysis <strong>of</strong> Spanish Niemann-<br />
Pick A/B disease patients.<br />
P12.122<br />
the Evaluation <strong>of</strong> clinical selection criteria in NsHL molecular<br />
Results<br />
C. Radaelli 1 , P. Castorina 2,3 , F. Lalatta 2 , U. Ambrosetti 3 , A. Cesarani 3 , A. Murri 4 ,<br />
D. Cuda 4 , F. Sironi 1 , L. Trotta 1 , D. A. Coviello 1 , P. Primignani 1 ;<br />
1 Medical <strong>Genetics</strong> Laboratory - Fondazione IRCCS, Ospedale Maggiore Policlinico,<br />
Mangiagalli e Regina Elena, Milan, Italy, 2 Medical Genetic Service<br />
- Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli e Regina<br />
Elena, Milan, Italy, 3 ENT Audiology Department - Fondazione IRCCS Ospedale<br />
Maggiore Policlinico, Mangiagalli e Regina Elena., Milan, Italy, 4 ENT Audiology<br />
Department - Ospedale “Guglielmo da Saliceto”, Piacenza, Italy.<br />
Since January 2001 we have studied more than 1000 subjects among<br />
deaf patients, family members and deaf/carrier partners.<br />
The majority <strong>of</strong> our patient’s population has been recruited through<br />
the Genetic Service <strong>of</strong> the O.R.L. Department <strong>of</strong> our Hospital in Milan<br />
since 2001 and through the O.R.L. Service in Piacenza starting from<br />
2004. The 658 subjects afferent to our Hospital were affected by neurosensorial<br />
deafness with various degrees (from mild to pr<strong>of</strong>ound) <strong>of</strong><br />
hearing loss (HL), while the 131 patients from Piacenza Hospital had a<br />
HL degree ranging from severe to pr<strong>of</strong>ound.<br />
All patients were analysed for mutations <strong>of</strong> the entire Cx26 gene<br />
(GJB2), and for the Δ(GJB6-D13S1830) deletion. The analysis <strong>of</strong> the<br />
deafness-causing A1555G substitution in mitochondrial (mt)DNA was<br />
carried out in our cohort <strong>of</strong> patients while, usually, in the second group<br />
this analysis is not requested. In order to compare the two different<br />
criteria <strong>of</strong> clinical selection and the concerning molecular results, we<br />
performed the mtDNA analysis in all the subjects with only one or without<br />
Cx26 mutations. In the first group we found a lower percentage <strong>of</strong><br />
positive Cx26/Cx30 cases in comparison to the second group (25.8%<br />
vs. 53.4%), but a higher percentage <strong>of</strong> dominant mutations (4.7% vs.<br />
1.5%); the mtA1555G was found only in the first group <strong>of</strong> the affected<br />
patients (3%). We conclude that clinical selection based on the severity<br />
<strong>of</strong> HL is quite relevant to obtain high percentage <strong>of</strong> Cx26 positive,<br />
but may allow the missing <strong>of</strong> uncommon GJB2 genotypes and mt mutations.<br />
P12.123<br />
Frequency <strong>of</strong> 35delG mutations in cochlear implant recipients .<br />
M. Falah1 , M. Houshmand2 , S. Akbaroghli3 , S. Seyedhassani2 , M. Farhadi1 ;<br />
1Department and research center <strong>of</strong> ENT and Head & neck surgery Iran University<br />
<strong>of</strong> Medical Sciences., Tehran, Islamic Republic <strong>of</strong> Iran, 2National Institute<br />
for Genetic Engineering and Biotechnology., Tehran, Islamic Republic <strong>of</strong> Iran,<br />
3Deputy for cultural affairs and prevention <strong>of</strong> Iran Welfare Organization, Tehran,<br />
Islamic Republic <strong>of</strong> Iran.<br />
Objective: Hearing impairment is the most common sensory disorder,<br />
present in 1 <strong>of</strong> every 500 newborns. Nonsyndromic sensorineural hearing<br />
loss(NSHL) is inherited in a predominantly autosomal recessive<br />
manner in up to 70% <strong>of</strong> cases. It is also an extremely heterogeneous<br />
trait. The gene more <strong>of</strong>ten involved is GJB2, encoding the protein Connexin<br />
26. In most populations a single mutation, 35delG, accounts for<br />
most cases <strong>of</strong> NSHI .<br />
Methods: 90 patients receiving cochlear implants were ascertained<br />
through research centre <strong>of</strong> ENT & head and neck surgery .After genetic<br />
counseling for them DNA isolated from the peripheral blood, all<br />
patients were molecularly evaluated for the presence <strong>of</strong> the 35delG<br />
mutation by ARMS /PCR.<br />
Result: We investigated 90 patients , 44.9% male and 55.1% female ,<br />
that 90% <strong>of</strong> them were < 10 years old that receiving cochlear implant<br />
.<br />
70.8% <strong>of</strong> these patients were born on consanguine family and 12.4%<br />
<strong>of</strong> them were syndromic hearing loss.<br />
Among these patients 86.5% were normal, 10.1 % homozygote and<br />
3.4% heterozygote for 35delG mutation.