European Human Genetics Conference 2007 June 16 – 19, 2007 ...

Molecular and biochemical basis of disease
caused by mutations in the MEFV gene. MEFV, expressed in granulocytes
and monocytes, encodes marenostrin/pyrin (M/P), a presumed
regulator of inflammation.
Recently, multiple alternatively spliced MEFV transcripts were identified
suggesting the existence of several proteins in vivo. The expression
pattern of the native protein has poorly been investigated especially
in cells physiologically expressing MEFV.
To address this issue, we performed RT-PCR analysis of MEFV mRNA
from human control peripheral blood leucocytes using exonic primers
spanning exon 1 to 10. The PCR products were cloned and directly
sequenced.
We identified two new transcripts due to alternative splicing events.
A complex transcript, MEFV-d2-9ext, resulted in an in-frame deletion
of exon 2 and a 5’ 117 bp extension of exon 9 introducing a premature
stop codon. The second transcript, MEFV-d2-3-4 was generated by
removal of exon 2, 3 and 4, resulting in a frameshift that predicts a
short protein corresponding to exon 1 only.
We raised polyclonal antibodies against 6 peptides designed from the
MEFV coding sequence, and detected by Western-blotting protein
isoforms that we are currently characterizing. Previous data and ours
strongly support that numerous MEFV transcripts are produced by alternative
splicing. Because alteration of MEFV expression regulation
may be involved in FMF pathophysiology, we will analyze the pattern
splicing of MEFV transcripts, in FMF patients.
P0734. Heteregenous clinical profile of familial mediterranean
fever associated to M680I (G/C) mutation in a Tunisian arab
muslim family from Sfax
N. B. Abdelmoula1 , N. Hmida2 , F. Thonney3 , T. Rebai1 ;
1 2 3 Faculty of Medicine, Sfax, Tunisia, Private Sector, Sfax, Tunisia, Centre Hospitalier
Universitaire Vaudois, Lausanne, Switzerland.
Familial Mediterranean fever (FMF) is an autosomal recessive disorder
particularly common in Mediterranean population,characterised by
recurring attacks of fever and serositis.
The cloning of the FMF gene on 16p13 and the subsequent finding
that its tissue expression is limited to granulocytes, has helped to explain
the dramatic accumulation of neutrophils at the symptomatic serosal
sites. The most frequent sequence alterations in MEFV gene are
M694V, V726A, M680I, M694I and E148Q. The wide clinical variability
of the disease has been related to MEFV allelic heterogeneity.
In this study, we report clinical profiles and molecular findings in a Tunisian
Arab Muslim family from Sfax town. Only two members of this
large consanguineous family fulfilled the diagnostic criteria for FMF
with typical acute and recurrent crises of fever and serosal inflammation,
leading improperly to abdominal surgery. Other subjects manifested
a mild or atypical phenotype. All members underwent molecular
genetic exploration to confirm diagnosis for some ones and establish
carrier status for others. Mutations were investigated by PCR amplification
and digestion with appropriate enzymes made to distinguish the
wild type from the mutant allele. Genetic analysis revealed a M680I
(G/C) mutation in all members of the family. Heterozygote members
were healthy but homozygotes were heterogeneously affected.
We discuss clinical presentations of FMF disease in this Arab Muslim
family and emphasize the role of genetic analysis.We conclude
that specific MEFV mutations are probably not the sole determinants
of phenotype, and that unknown environmental factors or modifying
genes act as accomplices in this disease.
P0735. Different expression of the P369S mutation in the MEFV
gene in the Armenian population
H. Hayrapetyan, T. Sarkisian, A. Egiazaryan, A. Arakelyan;
Center of Medical Genetics and Primary Health Care, Yerevan, Armenia.
Familial Mediterranean Fever (FMF) is the most prevalent hereditary
inflammatory disorder with diverse clinical presentation. The identification
of MEFV gene mutations causing the disease have provided an
important laboratory tool that helps in the diagnosis of FMF and perhaps
in understanding its heterogeneous clinical presentation.
Screening of healthy controls in Armenian population for MEFV mutations
compared with the distribution of the mutations in the patients,
has shown that P369S mutation is the most common in the normal
population (4.9%) but is less frequently represented in the patients
(0.1%). This suggests a reduced penetrance of P369S.
Among 250 controls we detected 10 genotypes with P369S complex
alleles, 7 were not associated with clinical FMF, and 3 manifested only
mild disease, suggesting that P369S might ameliorate the phenotypic
effect of exon 10 mutations.
We detected 12 mutations in 2400 individuals with clinical signs suggestive
of FMF and found P369S rare mutation in 14 of them: 9 heterozygotes,
3 compound heterozygotes (1 with P369S/F479L and 2
with P369S/E148Q), and 2 displayed complex alleles (P369S/E148Q/
R761H; P369S/E148Q/M694V). Evaluation of the phenotypic features
of the patients with P369S mutation showed the presence of 8 asymptomatic
individuals. Four patients with P369S mutation, one - with
P369S/E148Q and one - with P369S/E148Q/M694V had the FMF
clinical picture.
On the basis of our results and recent data, we suggest that in some
cases other factors along with MEFV genotype, such as environment
or possibly other genetic factors play a role in the determination of the
severity of the inflammatory attacks in FMF.
P0736. Disruption of conserved non-coding elements in a
t(2;3)(q12;p13)de novo
E. Engenheiro 1 , D. Goode 2 , A. Woolfe 2 , M. Pinto 3 , G. Soares 3 , Z. Tümer 1 , G.
Elgar 2 , N. Tommerup 1 ;
1 Wilhelm Johannsen Center for Functional Genome Research, Department of
Medical Genetics, Institute of Molecular and Cellular Medicine, University of
Copenhagen, Copenhagen, Denmark, 2 Functional Genomics Group, School of
Biological and Chemical Sciences, Queen Mary University of London, Mile End
Road, London, United Kingdom, 3 Instituto de Genética Médica Jacinto Magalhães,
Porto, Portugal.
It was recently discovered that not only can disruption of important
developmental genes cause disease, but so can disruption of the
regulatory landscapes surrounding these genes, e.g. by translocations
that remove regulatory elements from the gene they regulate. Here we
present a balanced t(2;3)(q12.3;p13)de novo in a patient with mental
retardation, speech defect and strabismus. The breakpoints were
mapped by FISH using BAC clones to a gene empty region upstream
of FOXP1 on chromosome 3p13. The breakpoint on chromosome 3p13
disrupts a cluster of conserved non-coding elements (CNEs) associated
with FOXP1. It has recently been shown that similar conserved
elements probably function as tissue-specific enhancers and that they
are important for the diverse spatio-temporal functions of the associated
key developmental genes. The disrupted elements upstream of
the breakpoint on chromosome 3p13 have been studied in vivo by a
functional assay using zebrafish. Several of these elements revealed
GFP expression in the zebrafish central nervous system. Recently,
FOXP2, which encodes another member of the Forkhead box (Fox)
family of proteins, has been identified as the gene underlying a human
developmental language abnormality. Since FOXP1 is specifically colocalized
with FOXP2 in the bird and human brain, it is predicted to be
related to speech disorders as well. The objectives of this study are to
identify regulatory sequences related to the candidate gene associated
with the 3p13 breakpoint in this translocation and contribute to the
understanding of the etiology of speech defect associated with mental
retardation and strabismus.
P0737. Frequency of FRAXA and FRAXE and polymorphism at
FMR1 and FMR2 genes in Indian population
K. Lavanya 1 , B. Thelma 2 , V. Om Sai Ramesh 3 , V. Naga Rathna 3 , M. Anandaraj
1 ;
1 Institute of Genetics & Hospital for Genetic Diseases, Hyderabad, India, 2 Department
of Genetics, Delhi University, New Delhi, India, 3 National Institute for
Mentally Handicapped, Secunderabad, India.
Fragile X syndrome (FRAX) is one of the main causes of mental retardation.
It is caused mainly by dynamic expansions at FMR1 (FRAXA)
and FMR2 (FRAXE) genes at Xq27.3 and Xq 28. In agreement with
the polymorphism of the CGG/CCG repeats and the methylation status
of the gene, the FRAXA and FRAXE alleles can be divided into
three categories; normal (2-60), premutation (60-200) and full mutation
(>200).
A total of 203 individuals (194 males; 9 females) with MR of unknown
etiology, were analyzed for the expansion and also for the polymorphism
at FMR1 and FMR2 genes. Radioactive-PCR and southern
blotting using Stb12.3 (for FRAXA) and Oxe20.0 (for FRAXE) were
employed in analyzing the patients. 5 males did not show amplification
for FRAXA allele because of the full mutation. These were again
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