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 />
P12.086<br />
Genetic heterogeneity <strong>of</strong> hereditary neuropathy with liability to<br />
pressure palsies at the Russian patients<br />
O. A. Schagina, T. B. Tiburkova, E. L. Dadali, G. E. Rudenskaya, A. V.<br />
Polyakov;<br />
Research centre for medical genetics RAMS, Moscow, Russian Federation.<br />
Hereditary neuropathy with liability to pressure palsies (HNPP) is an<br />
autosomal dominant painless peripheral neuropathy characterized<br />
by episodes <strong>of</strong> repeated focal pressure neuropathies at sites <strong>of</strong> entrapment/compression,<br />
with a considerable variability in the clinical<br />
course.<br />
Forty patients and twenty one healthy members from 26 unrelated<br />
families with a clinical history and examination suggestive <strong>of</strong> HNPP<br />
were observed. In 9 families HNPP were due to the common 1.5 Mb<br />
deletion. This mutation was detected on the basis <strong>of</strong> a PCR result that<br />
demonstrated loss <strong>of</strong> heterozygosity for each <strong>of</strong> four polymorphic markers<br />
in 17p11.2-12 region. Multiplex Ligation-dependent Probe Analysis<br />
(MLPA) was carried out for all patients and family members using a<br />
probes were designed to evaluate all PMP22 coding exons and five<br />
control genes: TBP, SIRT3, USP3, B2M and EEF. Disease-cause deletion<br />
was found at the three more unrelated families. At the three cases<br />
deletion de novo was the reason <strong>of</strong> disease and in the others families<br />
mutation persistence at several generations. At one patient the disease-cause<br />
duplication <strong>of</strong> 17p11.2-12 region were detect.<br />
In the absence <strong>of</strong> the deletion/duplication direct sequence analysis <strong>of</strong><br />
the all PMP22 coding exons 2-5, including their intron/exon boundaries<br />
was undertaken. One c.353C>T (Thr118Met) the previously described<br />
mutation in a heterozygotic condition and one new mutation<br />
c.75_78+2delCAGCgt were detected in two families.<br />
Thereby exciting cause was found in total at 15 from 26 unrelated families.<br />
In summary, we were able to detect genetic lesions in over 60% <strong>of</strong><br />
HNPP patients from Russia.<br />
P12.087<br />
Huntington disease pathogenesis: molecular biomarker/s in<br />
human peripheral blood and clonally striata-derived rat cells<br />
R. I. Lonigro1 , E. Bregant1 , L. Temil1 , F. Marcuzzi1 , N. Passon1 , G. Siciliano2 , E.<br />
Unti2 , G. Damante1 ;<br />
1Department <strong>of</strong> Science and Biomedical Technologies, University <strong>of</strong> Udine,<br />
Udine, Italy, 2Neuroscience Department, University <strong>of</strong> Pisa, Pisa, Italy.<br />
Huntington disease (HD) is an inherited neurodegenerative disease<br />
characterized by chorea and psychiatric disturbance. It is caused by<br />
the expansion <strong>of</strong> CAG repeats in the first exon <strong>of</strong> the gene encoding<br />
huntingtin (Htt). Normal people have a polymorphic repeat, up to 36<br />
CAG, encoding for glutamine (Gln). The mutant protein, with a longer<br />
poly-Q tract, becomes harmful to cells, particularly to cortical and<br />
striatal neurons. Mutant Htt affects many cellular processes, calcium<br />
homeostasis and mitochondrial dysfunction between others, still investigated<br />
to unveil their cause and effect relationship. An important tool<br />
for HD management could be the identification <strong>of</strong> molecular markers<br />
related to disease progression, in syntomatic and pre-symptomatic<br />
people, useful to draw early therapeutic treatments. By using quantitative<br />
RT-PCR we investigate the expression level <strong>of</strong> genes involved in<br />
calcium homeostasis in the peripheral blood <strong>of</strong> HD subjects and ageand<br />
gender- matched healthy controls. The genes selected for this<br />
study were: a purinergic receptor, P2RY5, and three calcium pumps,<br />
SERCA2, SERCA3 and PMCA1. The results we obtained demonstrate<br />
that, with respect to the controls HD patients display: 1) similar levels<br />
<strong>of</strong> SERCA3 and PMCA1 mRNAs. 2) a significant reduction <strong>of</strong> P2RY5<br />
mRNA level, in an age-related progression. 3) a significant reduction <strong>of</strong><br />
SERCA2 mRNA level at all ages. Furthermore, we propose SERCA2<br />
reduction as an early event in HD pathogenesis, since this pump is<br />
down-regulated at the protein level in clonally striata-derived rat cells<br />
expressing a doxycycline-inducible mutant Htt.<br />
P12.088<br />
Huntington disease pathogenesis: molecular biomarker/s in<br />
human peripheral blood and clonally striata-derived rat cells<br />
R. I. Lonigro 1 , E. Bregant 1 , L. Temil 1 , F. Marcuzzi 1 , N. Passon 1 , G. Siciliano 2 , E.<br />
Unti 2 , G. Damante 1 ;<br />
1 University, Udine, Italy, 2 University, Neuroscience Department, Pisa, Italy.<br />
Huntington disease (HD) is an inherited neurodegenerative disease<br />
characterized by chorea and psychiatric disturbance. It is caused by<br />
the expansion <strong>of</strong> CAG repeats in the first exon <strong>of</strong> the gene encoding<br />
huntingtin (Htt). Normal people have a polymorphic repeat, up to 36<br />
CAG, encoding for glutamine (Gln). The mutant protein, with a longer<br />
poly-Q tract, becomes harmful to cells, particularly to cortical and<br />
striatal neurons. Mutant Htt affects many cellular processes, calcium<br />
homeostasis and mitochondrial dysfunction between others, still investigated<br />
to unveil their cause and effect relationship. An important tool<br />
for HD management could be the identification <strong>of</strong> molecular markers<br />
related to disease progression, in syntomatic and pre-symptomatic<br />
people, useful to draw early therapeutic treatments. By using quantitative<br />
RT-PCR we investigate the expression level <strong>of</strong> genes involved in<br />
calcium homeostasis in the peripheral blood <strong>of</strong> HD subjects and age-<br />
and gender- matched healthy controls. The genes selected for this<br />
study were: a purinergic receptor, P2RY5, and three calcium pumps,<br />
SERCA2, SERCA3 and PMCA1. The results we obtained demonstrate<br />
that, with respect to the controls HD patients display: 1) similar levels<br />
<strong>of</strong> SERCA3 and PMCA1 mRNAs. 2) a significant reduction <strong>of</strong> P2RY5<br />
mRNA level, in an age-related progression. 3) a significant reduction <strong>of</strong><br />
SERCA2 mRNA level at all ages. Furthermore, we propose SERCA2<br />
reduction as an early event in HD pathogenesis, since this pump is<br />
down-regulated at the protein level in clonally striata-derived rat cells<br />
expressing a doxycycline-inducible mutant Htt.<br />
P12.089<br />
Exclusion <strong>of</strong> trinucleotide repeat expansions in JPH3 gene<br />
causing disease in italian patients with Huntington-like<br />
phenotype<br />
A. Patitucci, A. Magariello, T. Sprovieri, L. Citrigno, C. Ungaro, A. L. Gabriele,<br />
F. L. Conforti, R. Mazzei, M. Muglia;<br />
Institute <strong>of</strong> Neurological Sciences, CNR, Mangone (CS), Italy.<br />
Huntington disease-like 2 (HDL2) is a rare autosomal dominant disorder<br />
<strong>of</strong> the nervous system, apparently indistinguishable from Huntington<br />
disease (HD). HDL2 belongs to a group <strong>of</strong> HDL disorders, also<br />
including Huntington disease-like 1 (HDL1), an autosomal dominant<br />
disease caused by an extra octapeptide repeat in the prion protein<br />
gene (PRNP), on chromosome 20p12; and Huntington disease-like<br />
3 (HDL3), an autosomal recessive disease, mapped to 4p15.3. Furthermore,<br />
dentatorubral-pallidoluysian atrophy (DRPLA) and spinocerebellar<br />
ataxia type 17 (SCA17), may also have overlapping symptoms<br />
with HD.<br />
HDL2 is caused by the expansion above 40 CAG repeats, in a variably<br />
spliced exon <strong>of</strong> the junctophilin-3 gene (JPH3), on chromosome<br />
16q24.3. The pathogenic mechanism underlying HDL2 remains unknown.<br />
Different JPH3 transcripts caused by alternative splicing and<br />
different polyadenylation sites have been described.<br />
To date, the expansion in JPH3 gene has been found only in patients<br />
with African ancestry. A very recent paper reports the first HDL2 case<br />
with an apparent <strong>European</strong> ancestry. In order to find a new founder<br />
effect on Caucasian population, we performed a mutational analysis in<br />
JPH3 gene in 132 Italian patients negative for HD disease. All patients<br />
tested were negative for the expansion on JPH3 according to the available<br />
data on Polish, Yugoslavian and Portuguese populations.<br />
Further investigations for HDL1 and HDL3 forms, as well as DRPLA<br />
and SCA17, will be performed on our patients. However, the diagnosis<br />
<strong>of</strong> HDL2 should always be considered, regardless <strong>of</strong> the apparent origin<br />
<strong>of</strong> the family, particularly in populations <strong>of</strong> mixed ancestry.<br />
P12.090<br />
PcR <strong>of</strong> (cAG)n repeats in Bulgarian Huntington Horea patients<br />
A. Todorova 1 , T. Todorov 1 , B. Georgieva 1 , A. Kirov 1 , L. Angelova 2 , S. Kalenderova<br />
1 , V. Mitev 1 ;<br />
1 Department <strong>of</strong> Medical Chemistry and Biochemistry, Medical University, S<strong>of</strong>ia,<br />
Bulgaria, 2 Laboratory <strong>of</strong> Medical <strong>Genetics</strong>, Medical University, Varna, Bulgaria.<br />
Huntington disease (HD) is an autosomal dominant neurodegenerative<br />
disorder that gives rise to progressive, selective (localized) neural<br />
cell death associated with choreic movements, rigidity and dementia<br />
frequently associated with seizures. The disease is associated with<br />
increases in the length <strong>of</strong> a CAG triplet repeat in IT15 gene called<br />
‘huntingtin’ located on chromosome 4p16.3.<br />
The normal size <strong>of</strong> the CAG triplet <strong>of</strong> the HD is ≤35 repeats, the pathological<br />
number <strong>of</strong> the CAG triplet is larger than 36 repeats with different<br />
penetrance (36-39 repeats -