2008 Barcelona - European Society of Human Genetics

Normal variation, population genetics, genetic epidemiology
HbS in the French population, we studied a cohort of about 150 S/bthal
patients and we found 20 different thalassemic traits, 9 of them representing
79% of the patients . Spectrum of mutations vary depending on
the patients origin but one interesting finding is that in the group of patients
of unidentified origin (n = 31) we found the largest spectrum with
20 different mutations. This finding may be explained by the increasing
heterogeneity of the French population and the admixture of thalassemic
traits from various parts of the world with the HbS . In France,
newborns belonging to populations at risk are screened for SCA by
means of IEF and CE-HPLC of Hb eluted from a dried blood spot . In
order to know the proportion of incorrectly diagnosed newborns we
extracted DNA from blood spot and genotyped the codon 6 . Results
obtained with 100 spots diagnosed as “S/S” with Hb study, revealed
that 15% of samples displayed one Hb S allele and one normal codon
and thus were improperly diagnosed . These data, lead us to develop
a fast and simple method which will allow to provide an “one shot” correct
diagnosis of SCA and related syndromes in neonates .
P07.017
Genetic heterogeneity of β-thalassaemia in Catalonia: molecular
characterization of 74 cases
M. Mañú-Pereira1 , A. Cabot2 , N. Radó1 , J. Vives-Corrons1 ;
1 2 Hospital Clínic i Provincial, Barcelona, Spain, Hospital de Mataró, Barcelona,
Spain.
Introduction: A study performed in Catalonia in 1988 showed 8 mutations
responsible for the total of β-thalassaemia cases. The objective
is to investigate the β-thalassaemia underlying mutations to ensure
proper genetic counseling and prenatal diagnosis . We also describe a
new β-thalassaemia mutation.
Methods: 74 patients for β-thalassaemia were studied. The 8 most prevalent
mutations (>90%) of β-globin in the Mediterranean: CD39(C>T),
IVS1:110(G>A), IVS1:6(T>C), IVS1:1(G>A), IVS2:745(C>G),
IVS2:1(G>A), -87(C>G), CD6(-A) were screened by ASO . Negative
samples were sequenced for β-globin gene.
Results: Distribution of the identified β-gene mutations and data of
1988 are shown in Table 1 .
Discussion: Identification of mutation leading to β-thalassaemia by
analyzing the most prevalent mutations in the Mediterranean has
decreased 15-25% . The 4 mutations most prevalent in our study are
common in the West Mediterranean but the last 4 considered prevalent
are responsible only for 2 .8% of our cases . In comparison with the
1988 study, analysis of the 8 mutations then identified is responsible
for 82 .6% in the recent study, changing the relative percentage . Molecular
heterogeneity has increased: 19 mutations, including Chinese
and sub-Saharan variants are now responsible for all cases . Since
immigration flows and increased rates of rare and even new variants
make genetic diagnosis more difficult, this shows the high importance
of identifying β-thalassaemia mutations in order to provide appropriate
genetic counseling and prenatal diagnosis
mUtAtiON ORiGiN % 2007 % 1988
Prevalent mutations
CD39 C>T
17 Spain 1 Italy 1 Russia
1 Morocco 1 Subsaharian
28 .4 64 .0
IVSI:110 G>A 9 Spain 12 .2 8 .5
IVSI:6 T>C 6 Spain 5 Egypt 14 .9 15 .5
IVSI:1 G>A
10 Spain 1 Russia
1 Morocco
16 .2 3 .5
IVSII:745 C>G 1 Spain 1 .4 1 .7
IVSII:1 G>A - - -
-87 C>G - - -
CD6 -A 1 Morocco 1 .4 5
mUtAtiON ORiGiN % 2007 % 1988
Other mutations
CD8 -AA 1 Spain 3 Morocco 5 .4 1 .7
IVSI:5 G>C 1 Spain 1 Morocco 2 .7 1 .5
CD8/9 +G 1 Spain 1 Morocco 2 .7 -
CD41/42 -TTCT 2 China 2 .7 -
CD24 T>A 2 Subsaharian 2 .7 -
CD6 -AG* 2 Spain 2 .7 -
CD37 G>A 1 Spain 1 .4 -
IVSI:1 G>T 1 India 1 .4 -
IVSII:849 A>C 1 Subsaharian 1 .4 -
-29 A>G 1 Subsaharian 1 .4 -
-88 C>T 1 Spain 1 .4 -
P07.018
Polymorphism in caRs A986s gene and serum or urine
concentration of bone mineral related parameters in random
selected postmenopausal women .
L. Navarro Casado, J. A. Blázquez Cabrera, C. Andrés Fernández, M. Cháfer
Rudilla, J. H. Ontañón Rodríguez, M. L. Quintanilla Mata;
CHUA, Albacete, Spain.
Background. Calcium-sensing receptor (CaSR) is a candidate gene for
osteoporosis susceptibility . There are only a limited number of studies
available regarding the relationship between the CaSR gene A986S
polymorphism and serum or urine concentration of bone mineral related
parameters .
Objectives. To evaluate whether CaSR gene A986S polymorphism affects
bone mineral related parameters on serum as: calcium (s-ca),
phosphorus (s-ph), alkaline phosphatase (s-alp), acide phosphatase
(s-acp), or on urine as calcium creatinine ratio (u-ccr) .
Subjects and methods. 158 women with natural menopause were randomly
selected (mean age 52 .7±1 .6 yr) . They did not have any diseases
to affect bone metabolism . Genomic DNA was extracted from
peripheral blood leukocytes by the Higuchi method . A fragment of exon
7 of CaSR gene containing the A986S polymorphism was amplified by
polymerase chain reaction (PCR). After amplification, all samples were
digested whit Bsa H1 restriction enzymes, and the fragments were
separated by agarose gel electrophoresis . The levels of s-ca, s-ph, salp,
s-acp or u-ccr were measured by P-module from Roche .
Results. Genotype frequencies of CaSR gene A986S polymorphism
was: AA, 121 (76 .6%); AS, 34 (21 .5%), and SS, 3 (1 .9%) . We found no
association between CaSR polymorphism and s-ca, s-ph, s-alp, s-acp .
Women with the AS/SS genotype had higher u-ccr than those with AA
genotype, (AS/SS 0 .205 ± 0 .88; AA, 0 .167 ± 0 .76 mg/mg; p=0 .014 ) .
Conclusions . 1) We found no association between CaSR gene A986S
polymorphism and serum concentration of bone mineral related parameters
. 2) We found association between CaSR gene A986S and
calcium creatinine ratio .
P07.019
BRcA1 and BRcA2 sequence variants in healthy women in
croatia
M. Levačić Cvok, V. Musani, M. Čretnik, P. Ozretić, S. Levanat;
Rudjer Boskovic Institute, Zagreb, Croatia.
BRCA1 and BRCA2 are the major genes predisposing to breast and
ovarian cancer . Mutations in either of these tumor suppressor genes
are associated with both sporadic and hereditary forms of breast cancer
. In hereditary cancer, a person inherits one mutated copy of either
one of these genes . Tumorigenesis occurs when in addition to having
a mutated copy individual develops an inactivating mutation of the remaining
healthy allele .
Breast cancer is the most common malignant disease of female population,
and the second most common malignancy-related cause of
death . At least ten percent of cases are attributable to familial inheritance
. In Croatia, more than 2200 new cases of breast cancer are
diagnosed each year, and about 800 women die of this malignancy .
The screening was performed by high resolution melting approach,
which is based on differences in melting curves caused by variations
in nucleotide sequence; detected variants were confirmed by direct
sequencing .
In total, we analyzed 230 samples for BRCA1 gene and 140 samples