European Human Genetics Conference 2007 June 16 – 19, 2007 ...
European Human Genetics Conference 2007 June 16 – 19, 2007 ...
European Human Genetics Conference 2007 June 16 – 19, 2007 ...
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Molecular and biochemical basis of disease<br />
The precise function of COX<strong>16</strong> is unknown. Its small size suggests<br />
that it doesn’t have a catalytic role, but rather that it could act by stabilizing<br />
nascent COX subcomplexes in analogy to PET100. The effect<br />
of COX<strong>16</strong> silencing on COX activity is striking, suggesting that COX<strong>16</strong><br />
may play an important role in the regulation of the COX assembly process.<br />
The role of COX<strong>16</strong> in COX deficiency has yet to be determined. A<br />
previous study failed to detect mutations in patients with isolated COX<br />
deficiency, we are now screening a novel cohort of patients for mutations<br />
in this gene.<br />
P0857. Investigation of the Spinocerebellar ataxia type 10<br />
mutation in the Cypriot population<br />
C. Votsi, A. Georghiou, T. Kyriakides, M. Pantzaris, S. Papacostas, E. Zamba-<br />
Papanicolaou, K. Christodoulou;<br />
The Cyprus Institute of Neurology and <strong>Genetics</strong>, Nicosia, Cyprus.<br />
Spinocerebellar ataxia type 10 belongs to the group of neurodegenerative<br />
diseases known as autosomal dominant cerebellar ataxias. Genetic<br />
studies in patients with SCA so far revealed 12 genes responsible<br />
for ADSCA and 12 mapped loci without gene identification. SCA10 is<br />
characterized by progressive ataxia and seizures. The underlying mutation<br />
is a large expansion of an ATTCT repeat in intron 9 of the SCA10<br />
gene. Our aim is to determine the relative frequency of SCA10 in Cyprus,<br />
which constitutes part of our wider effort to identify the genetic<br />
defects of the Cypriot SCA sporadic patients and families, which prove<br />
to be exceptional in comparison with other populations. We analyzed<br />
the ATTCT repeats in 37 SCA patients, previously excluded from other<br />
genes (FRDA, SCA1-3, SCA6-8, SCA12, SCA17 and DRPLA). We<br />
also determined the size of repeats in 57 normal controls from the<br />
Cypriot polulation. The repeat lengths were analyzed by polymerase<br />
chain reaction followed by fragment analysis. Southern blot analysis<br />
is currently performed for samples with one allele detected, in order<br />
to confirm homozygosity or presence of a SCA10 expansion. Normal<br />
control sample repeat lengths ranged from 11 to 20 with 82,5% heterozygosity<br />
and the 14 repeats allele is more frequent (38%) in the<br />
Cypriot population. In the patient group, repeats ranged from 12 to18<br />
with 73% heterozygosity. Three patients have already been confirmed<br />
to be homozygous for a normal range allele. In conclusion, our results<br />
agree with other studies demonstrating that SCA10 is rare in polulations<br />
other than the Mexican.<br />
P0858. SCA17 transgenic mice exhibit a neurodegenerative<br />
phenotype<br />
H. Nguyen, C. Bauer, T. Ott, T. Hennek, O. Riess, P. Bauer;<br />
Department of Medical <strong>Genetics</strong>, Tübingen, Germany.<br />
SCA17 is a progressive neurodegenerative disease leading to cerebellar<br />
ataxia and dementia. Several accessorial symptoms such as<br />
Parkinsonism, dystonia, and psychiatric disturbances commonly aggravate<br />
the disease course. Genetically, a CAG/CAA expansion in the<br />
TATA binding protein (TBP) is expanded in SCA17 patients, leading to<br />
an expanded polyglutamine chain in this ubiquitously expressed transcription<br />
factor.<br />
We have generated transgenic mice overexpressing a 64 CAG/CAA<br />
repeats containing human TBP (Q64TBP) gene under the control of<br />
the truncated human prion protein promoter (PrP).<br />
Transgene protein expression throughout different brain regions (cortex,<br />
basal ganglia, cerebellum, and brain stem) was clearly demonstrable.<br />
Onset of motor dysfunction (Accellerod) started by 20 weeks<br />
and the life span of transgenic animals was reduced.<br />
We present detailed morphological and phenotypical data for this rodent<br />
model of SCA17, which enables us to further study the pathogenesis<br />
of this progressive neurodegenerative disease.<br />
P0859. SOST gene mutation in two Brazilian families with<br />
sclerosteosis<br />
C. A. Kim1 , R. S. Honjo1 , D. R. Bertola1 , L. M. J. Albano1 , L. A. N. Oliveira1 , S.<br />
M. C. P. Jales1 , J. T. T. Siqueira1 , W. Balemans2 , E. Piters2 , K. Jennes2 , W. van<br />
Hul2 ;<br />
1 2 Instituto da Criança, São Paulo, Brazil, Department of Medical <strong>Genetics</strong>, Antwerpen,<br />
Belgium.<br />
Sclerosteosis is a rare, autosomal recessive disease characterized by<br />
a progressive craniotubular hyperostosis. The main features are: high<br />
stature, nail dysplasia, cutaneous syndactyly of some fingers, signifi-<br />
22<br />
cant sclerosis of the long bones, ribs, pelvis and skull, leading to facial<br />
distortion and entrapment of cranial nerves. The sclerosteosis gene<br />
has been mapped to 17q12-21 and is known as the SOST gene encoding<br />
sclerostin protein. We report on one familial and one sporadic<br />
case with clinical and molecular diagnosis of sclerosteosis.<br />
Case 1: 34-year-old male, with difficulty in opening mouth, hemifacial<br />
and tongue pain, gustatory hyperlacrimation and hypoacusis. Four<br />
sisters had similar clinical complaints, three of whom had cutaneous<br />
syndactyly of some fingers. Physical examination: macrocephaly, long<br />
face and widely spaced teeth. Radiological studies: poor development<br />
of the mandible angle, asymmetric face, sclerosis of the skull and craniofacial<br />
bones, hyperostosis of the ribs, pelvis and long bones.<br />
Case 2: 6-year-old girl, presented with recurrent facial paralysis. There<br />
was no significant facial dysmorfism. Cutaneous syndactyly of the index<br />
and middle fingers was present. Radiological studies: sclerosis of<br />
the skull, spine, pelvis and long bones.<br />
The clinical diagnosis of sclerosteosis in both cases was confirmed<br />
by analysis of the SOST gene showing the same mutation (Trp124X).<br />
We reported this mutation previously in other Brazilian patients. Curiously,<br />
both families were from the same state in Brazil, but they denied<br />
familial relationship.<br />
In conclusion, these patients confirm the clinical picture as found in<br />
other cases with a loss of function mutation in the SOST gene.<br />
P0860. Determining the expression of the human SPP2 in<br />
lymphocytes, endothelial cells and monocytes and the effect of<br />
TNF-α and LPS on the expression using RT-PCR method<br />
H. Khorram Khorshid 1 , R. Dalgleish 2 ;<br />
1 Genetic Research Centre, The Social Welfare and Rehabilitation Sciences<br />
University, Tehran, Islamic Republic of Iran, 2 Department of <strong>Genetics</strong>, University<br />
of Leicester, Leicester, United Kingdom.<br />
Secreted phosphoprotein 24 (spp24) is a member of the cystatin superfamily<br />
and was first identified in cattle as a minor component of<br />
cortical bone. Subsequently it was recognised as a component of the<br />
fetuin-mineral complex. In the original study, the expression of the<br />
gene encoding spp24 (Spp2) was demonstrated in bovine bone periosteum<br />
and liver and it was later demonstrated that Spp2 is expressed<br />
in chicken and mouse T-cells and also in the mouse thymus. Hence, it<br />
was decided to investigate the expression pattern of the human spp24<br />
gene (SPP2) in peripheral white blood cells.<br />
Mononuclear lymphocytes and monocytes were isolated from whole<br />
fresh human blood and endothelial cells were prepared from the umbilical<br />
cord of a neonate. PCR amplification of reverse-transcribed<br />
mRNA indicated that SPP2 is expressed in human lymphocytes and<br />
endothelial cells, but not in monocytes.<br />
The effects of lipopolysaccharide (LPS) and tumour necrosis factor<br />
alpha (TNFα) on the expression of the human SPP2 gene were studied<br />
by their addition to cultures of monocytes, mononuclear cells and<br />
endothelial cells for up to 24 hours. Under standard culture conditions,<br />
which included bovine serum albumin (BSA) in the culture medium,<br />
there is expression of SPP2 in mononuclear lymphocytes and in endothelial<br />
cells at <strong>16</strong> hours, but not in monocytes. The addition of either<br />
LPS or TNFα down-regulates SPP2 expression in lymphocytes in a<br />
time-dependent fashion. However, the down-regulation effect of TNFα<br />
on endothelial cells is, by comparison, only modest. These findings<br />
may help us understand the function of spp24.<br />
P0861. Mitochondrial DNA instability and recessive POLG<br />
mutations in patients with isolated adult-onset sensory ataxic<br />
neuropathy<br />
S. Bannwarth 1,2 , K. Fragaki 1,2 , J. Pouget 3 , D. Figarella-Branger 4 , V. Paquis-<br />
Flucklinger 1,2 ;<br />
1 Department of Medical <strong>Genetics</strong>, Nice, France, 2 UMR CNRS 6543, Nice,<br />
France, 3 Department of Neurology, Marseille, France, 4 Department of Anatomopathology,<br />
Marseille, France.<br />
Nuclear gene defects affecting mtDNA stability include the mtDNA<br />
polymerase (POLG), the adenine nucleotide transporter (ANT1) and<br />
the Twinkle helicase. There is a considerable variability in the phenotype<br />
associated with POLG mutations which are responsible for<br />
autosomal dominant and recessive progressive external ophtalmoplegia<br />
(PEO), Alpers syndrome, a sensory ataxic neuropathy, dysarthria<br />
and ophtalmoparesis (SANDO) and a mitochondrial recessive ataxic<br />
syndrome. Nevertheless, patients with POLG mutations and sensory