2008 Barcelona - European Society of Human Genetics

Molecular and biochemical basis of disease
is toxic to cells, not least due to its ability to catalyze, via the so-called
Fenton reaction, the generation of aggressive free radicals . Therefore,
every organism has mechanisms to control cellular uptake, distribution,
detoxification and elimination of copper. Genetic defects in any of
these mechanisms as well as ecological abnormalities of copper balance
result in neurodegenerative diseases . The systems that maintain
copper homeostasis in mammalian brain are investigated poorly .
This work was done using Wistar rats received 50 mg AgCl per kg of
body weight, daily, in four weeks . This model is characterized with copper-deficit
in blood serum and normal copper metabolism in liver.
Concentration of copper, zinc, iron, and silver was determined in cortex,
cerebellum, hippocamp, hypothalamus, amygdaloid body, hypophysis
by atomic-absorptive spectrometry . Copper-transporting proteins
(CTR1, ATP7A/B, APP) and cuproenzymes (ceruloplasmin (Cp),
GPI-Cp, SOD1, COX (Cox4i1)) mRNA levels were determined with
semiquantitative RT-PCR . Protein amounts were valued by Westernblot
. Furthermore Cp and SOD1 enzymatic activity were measured .
It was shown that Ag-ions are selectively accumulated by hypophysis .
Hypophysis accumulates Fe and Zn as well . Cu level is decreased
in hypothalamus only . At the same time copper-transporting genes
expression is going lower in all brain regions . The same is right for
secretory cuproenzymes (Cp, GPI-Cp) . While level of intracellular cuproenzymes
(SOD1, COX) doesn’t change. Effect of copper deficit in
blood on copper metabolism in brain regions is discussed .
P05.140
Differential expression of neurokinin B and hemokinin 1 in
human immune cells
T. E. Klassert 1 , F. Pinto 2 , M. Hernández 1 , M. L. Candenas 2 , M. López 1 , M. C.
Hernández 3 , J. Abreu 3 , T. A. Almeida 1 ;
1 Instituto Universitario de Enfermedades Tropicales de Canarias, La Laguna,
Spain, 2 Instituto de Investigaciones Químicas, CSIC, Sevilla, Spain, 3 Departamento
de Neumología, Hospital Universitario de Canarias, La Laguna, Spain.
Substance P (SP), neurokinin A (NKA), neurokinin B (NKB) and the
recently identified hemokinin-1 (HK-1) are members of a family of
structurally related peptides known as tachykinins . They are mainly
synthesized in the central and peripheral nervous system, but are also
present in peripheral non-neuronal cells .
In humans, substance P (SP) is the most extensively studied tachykinin
and is present, along with the NK-1 receptor, in several inflammatory
and immune cells . In these cells, SP has shown to play an important
role in the regulation of immune functions and inflammatory responses.
Up to day, there are no studies about the expression pattern of NKB
and HK-1 in inflammatory and immune cells in humans. In the present
study we have detected for the first time NKB and HK-1 mRNA in
human lymphocytes, monocytes, neutrophils and eosinophils . In addition,
and using immunocytochemistry with two different antibodies, we
have detected the presence of NKB protein in all these cellular types .
These findings reinforce the suggestion that tachykinins play a central
role in the pathophysiology of the inflammatory process.
P05.141
Crosstalk between NF-kappaB and Wnt/beta-catenin pathways
and anhidrotic ectodermal dysplasia
C. Cluzeau1 , E. Bal1 , P. Guigue1 , N. Chassaing2 , S. Hadj-Rabia1,3 , C. Bodemer1,3
, P. Calvas2 , M. Vincent2 , A. Munnich1 , A. Smahi1 ;
1 2 INSERM U781, Paris, France, Service de genetique medicale, Toulouse,
France, 3Service de dermatologie, Paris, France.
Anhidrotic ectodermal dysplasia (EDA) is an ectodermal differentiation
disorder characterized by sparse hair, abnormal or missing teeth and
inability to sweat . X-linked EDA, caused by mutations in EDA gene
encoding ectodysplasine, a member of the TNF family, is the most
frequent form . The autosomal dominant and recessive EDA forms,
clinically identical to X-linked forms, may result from mutations in two
loci : ED3, encoding Edar, ectodysplasin receptor and ED2, encoding
Edaradd, Edar adapter molecule necessary in signal transduction .
Edar is activated by ectodysplasine and uses Edaradd as an adapter
to activate NF-kappaB signaling pathway . Wnt/beta-catenin pathway
plays a central role during embryonic development and is widely involved
in carcinogenesis . This pathway has been recently involved in
skin appendages formation . A crosstalk between NF-kappaB and Wnt/
beta-catenin pathway was described .
We confirmed by transactivation experiments that Edar receptor inhib-
its Wnt/beta-catenin pathway . We then studied the effects of seven recessive
and dominant mutations identified in Edar gene on both pathways
. Dominant mutations totally impaired NF-kappaB activation and
Wnt/beta-catenin downregulation, while recessive ones only disrupted
the Edar effect on both pathways .
We first demonstrated that Wnt/beta-catenin inhibition by Edar is dependent
of NF-kappaB activation using a dominant negative form of
IkappaBalpha inhibitor . We then proved by Western Blot analysis and
immunofluorescence that beta-catenin was neither degraded nor delocalized
after NF-kappaB activation by Edar . Furthermore, beta-catenin/
TCF4 interaction, necessary for Wnt/beta-catenin transcriptional activity,
was not disrupted upon Edar transfection and NF-kappaB subunits
p65 and p50 did not interact with beta-catenin in these conditions .
P05.142
Nijmegen breakage syndrome in Ukraine: molecular and
cytogenetic studies
H. Makukh 1 , L. Chorna 1 , B. Tretjak 1 , H. Bezkorovaina 1 , G. Akopian 1 , L.
Kostyuchenko 2 , N. Markevush 1 ;
1 State institution “Institute of Hereditary Pathology of Academy of Medical
Science of Ukraine”, Lviv, Ukraine, 2 Lviv Specialized Children’s Clinic, Lviv,
Ukraine.
Nijmegen breakage syndrome (NBS) is considered as a rare autosomal
recessive disease, but its actual prevalence is not known . 95% of
NBS patients are of Slavic descent and 90% of them are homozygous
for a founder 657del5 mutation in the NBN gene . In 1999-2007 a total
of 26 patients were diagnosed with NBS in Ukraine, 23 of which residing
in Western Ukraine region .
We performed 208 molecular-genetic tests of the 657del5 mutation
NBN gene among the group of patients with microcephaly and identified
24 homozygous for 657del5 mutation. It had been performed 4
prenatal NBS diagnostics and we identified two homozygous and two
heterozygous fetus for 657del5 mutation .
We detected the specific chromosomal rearrangements in lymphocyte
cell culture of NBS patients: 3% of the cases - inv(7)(p13q35),
2% - t(7;14)(q35;q11), t(7;7)(p13;q35), del(7)(q35), del(14)(q11), 1%
- t(7;14)(p13;q11) . An additional marker chromosome (10% of the
cells with translocations) and nonspecific chromosomal abnormalities
(mostly 1, 3, 8 and 9) were found too .
As the expression of IL-10 may influence the development and progression
of tumor we studied the distribution of three biallelic polymorphisms
at positions -1082, -819 and -592 of the promoter region
of IL-10 gene . The haplotype IL-10 GCC (37%) was found to be the
most frequent .
P05.143
Genetic heterogeneity of nonbullous congenital ichthyosiform
erythroderma
N. N. Vasserman, V. A. Galkina, O. N. Makienko, E. G. Okuneva, G. E. Rudenskaya;
Research Center for Medical Genetics, Moscow, Russian Federation.
Nonbullous congenital ichthyosiform erythroderma (NCIE, MIM
242100) is a severe autosomal recessive disorder . About 90% of affected
newborns present as “collodion babies” . Many patients die in
neonatal period from disorders of thermoregulation and infections . In
survivors, though, skin lesions improve with age, few patients have
neurological symptoms, while others live with little or no problems .
NCIE is genetically heterogeneous . To date, TGM1, ALOX12B, AL-
OXE3, ABCA12, CYP4F22 responsible genes were identified, and
mutations in the latter two are rare .
We performed DNA diagnostics in five NCIE families of which mutations
were found in four: one of Azerbaijan and three of Russian ethnicity
. (1) In a consanguineous Azerbaijan family two affected children
died within first days, their DNA samples were unavailable. In parents
a novel TCM1 mutation Arg142His was detected . On prenatal DNA
diagnostics the mutation was not found in the fetus, thus the prognosis
was favourable . (2) The couple abandoned the affected baby and
had no information about him . Parents were found heterozygous for
novel ALOX12B mutations: Ala597Glu and Tyr97Stop . Prenatal DNA
diagnostics revealed unfavourable prognosis since the fetus inherited
mutations from both parents . (3) In a family with a deceased newborn
child a novel ALOX12 mutation Asn594His was identified in the
father and a previously recorded Tyr521Cys in the mother . (4) In a
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