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

Clinical genetics
PCR with a modified primer and use of the restriction enzyme PsiI and
agarose gel electrophoresis. By testing 100 individuals of the general
population we found that allele 5T has a frequency of 3.5%. In six men
with azoospermia or CF patients with a single known mutation, the 5T
allele was not found. Also, allele 13TG was not found in 10 random
samples that were sequenced. The 5T allele does not seem to contribute
to pathology in our population, unless it is found in combination
with other mutations on undiagnosed patients.
P0077. Estimation of CFTR mutation carrier frequency in Iran
based on known frequency of p.F508del
H. Nezari 1 , S. S. Banihosseini 2 , R. Kalhor 3 , A. Khodadad 4 , F. Mirzajani 5 , E.
Elahi 1 ;
1 University of Tehran, Faculty of Sciences, Tehran, Islamic Republic of Iran,
2 Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran, 3 University
of Tehran, Dept Biotechnology, Faculty of Sciences, Tehran, Islamic
Republic of Iran, 4 Children’s Hospital Medical Center, Tehran University of Medical
Sciences, Tehran, Islamic Republic of Iran, 5 National Institute for Genetic
Engineering and Biotechnology, Tehran, Islamic Republic of Iran.
Cystic Fibrosis (CF) is the most common life-threatening autosomal
recessive disease in many Caucasian populations. Approximately one
in 2500 newborns in populations of European ancestry are affected,
wherein the average carrier frequency is 1:25. The disease is caused
by mutations in CFTR gene. Among the more than 1000 mutations
identified in the CFTR gene, the p.F508del allele is the most common
worldwide. Its frequency exhibits a northwest to southeast gradient,
ranging from a high of 88% in Denmark to a low of approximately 16%
in Iran. It has generally been believed that the incidence of CF also
follows a northwest to southeast gradient and that incidence in low
in non-European populations. However, relatively high incidences of
CF were predicted in Turkey and Iran based on data of frequency of
individuals carrying homozygous mutations and extent of inbreeding
in those populations. Specifically the carrier frequency in Iran was estimated
to be 1:40, similar to that of European populations. We have
now experimentally determined the frequency of p.F508del carriers
among 500 randomly selected Iranians. Based on the number of carriers
identified and the observation that this allele accounts for 16%
of the CFTR mutated alleles of the Iranian population, the frequency
of carriers of CFTR mutations was calculated to be 0.037 (95% confidence
level of 0.037+/- 0.016). This figure corresponds to 1:27, close
to the carrier frequency previously estimated. It is concluded that CF is
a disease of considerable public health importance in Iran, and probably
in other countries of the Middle East.
P0078. Description of large CFTR gene rearrangements in Italian
population
V. Paracchini 1 , C. Colombo 2 , L. Porcaro 1 , L. Costantino 1 , P. Capasso 1 , D. Degiorgio
1 , D. Coviello 1 , L. Claut 2 , R. Padoan 3 , M. Seia 1 ;
1 Fondazione IRCCS Opedale Maggiore Policlinico, Mangiagalli e Regina Elena,
Milan, Italy, 2 Cystic Fibrosis Centre - Fondazione IRCCS Opedale Maggiore
Policlinico, Mangiagalli e Regina Elena, Milan, Italy, 3 Cystic Fibrosis Support
Centre - A.O. Spedali Civili, Brescia, Italy.
Cystic fibrosis (CF) is mainly caused by small molecular defects of the
CFTR gene; despite the genotype is define in the majority of patients,
a number of CF cases still remain uncharacterized. These unidentified
mutations may escape detection using PCR-base techniques. The CF
mutation database lists more than 25 large rearrangements.
We report here the results of our screening for CTFR gene rearrangements,
performed on Italian CF patients.
A sample of 689 unrelated Italian patients (for a total of 1378 alleles),
followed at CF Centre of Regione Lombardia (Milan, Italy), was collected.
All patients had classical form of CF with typical pulmonary and
gastrointestinal findings, and positive sweat test.
The Innogenetics assay and the DHPLC screening showed a mutation
detection rate of 93%. After these analyses , 100 alleles still remain
unidentified (7%).
In order to detect the rearrangements in the CFTR gene, the 27 exons
were screened in these patients with the MLPA assay based on commercial
Kit “SALSA P091 CFTR MALPA Kit” .
The MLPA assay was performed for 38 patients (76 alleles).
We characterized 10 different deletions for a total of 19 deleted alleles.
In conclusion, 25% (19/76) alleles had a large gene deletion. The deletion
of exons 22-23 (6/76) is the most frequent in our cohort.
The analysis of CF patients performed with MLPA techniques has
made possible to reach a 94.4% detection rate, improving the process
of carrier detection and genetic counselling in Italian population.
P0079. Cystic Fibrosis: A frequent disease with heterogenous
mutation spectrum in Iran
R. Mirfakhraie 1 , M. Gorgipoor 2 , M. Houshmand 3 , H. Kianifar 4 , M. Rafiee 5 , E.
Talachian 6 , F. Mirzajani 3 ;
1 Islamic Azad University of Tehran, Science & Research Campus, Tehran,
Islamic Republic of Iran, 2 Khatam University, Tehran, Islamic Republic of Iran,
3 National Institute of Genetic Engineering & Biotechnology, Tehran, Islamic
Republic of Iran, 4 Mashhad Medical University, Mashhad, Islamic Republic of
Iran, 5 Tabriz Medical University, Tabriz, Islamic Republic of Iran, 6 Iran Medical
University, Tehran, Islamic Republic of Iran.
Cystic fibrosis (CF) is the most common autosomal recessive disorder
in European populations with about 1:25 carrier frequency and regional
variation. Since the identification of the cystic fibrosis transmembrane
regulator (CFTR) gene, over 1000 mutations have been reported in
which ΔF508 is the most frequent. However for non European populations,
the incidence of CF and the spectrum of mutations that are
responsible for the disease are not critically assessed.
A few comprehensive studies are focused on the molecular basis of
CF in the Iranian population. In this research we are going to present
the results obtained from a 4 year study on the 110 Iranian CF patients
including molecular analysis of the CFTR gene.
Our results suggest that CF is a very heterogenic disease among our
population in which about 15 different mutations and polymorphisms
have been detected till now. DelF508, G542X, N1303K, G551D and
W1282X, the 5 most common mutations in Europeans with the overall
frequency of 75%, only contain 23% of CFTR mutant alleles in Iran.
The other detected mutations are rare with relative frequencies of
lower than 1%.
The information provided here on the distribution of CF mutations in
Iranian population may assist in the development of more appropriate
diagnosis tests in Iran and also it may facilitates the mutation analysis
in the neighboring countries.
P0080. 8-Years experience in cystic fibrosis neonatal screening
in Castilla-Leon (Spain)
M. Alonso1,2 , J. Telleria1,2 , I. Fernandez1,2 , A. Blanco1,2 ;
1IBGM (Instituto de Bioloogía y Genética Molecular), VALLADOLID, Spain,
2Universidad Valladolid, Valladolid, Spain.
Since the implementation of the Cystic Fibrosis (CF) Newborn Screening
in our region in 1999, we have analysed 126.385 newborn samples
for CF. According to the Guidelines of the European Concerted Action
of Cystic Fibrosis our protocol combines the assay of immunoreactive
trypsinogen (IRT) with the analysis of the most common mutations of
the CFTR gene in our population . Thus, the IRT raised samples are
analysed for the F508del mutation with the PAGE method, and for the
exons 7, 11, 12, 13, 14b and 17b by DGGE . The coverage of this
study in our population reaches the 83% of CF causing mutations. The
diagnose is established when two CF causing mutations are detected,
or when only one mutation is detected but the sweat test is positive.
Newborns with only one mutation detected but negative sweat test are
considered carriers .
RESULTS:
Irt RAISED
YEAR NEWBORNS
CF CARRIERS
SAMPLES
1999 17.128 141 5 1
2000 17.698 97 2 8
2001 17.380 146 5 10
2002 17.835 195 5 9
2003 18.395 210 3 15
2004 18.900 150 4 10
2005 19.049 169 7 11
2006 19.431 159 2 11
TOTAL 126.385 1267 33 75
Additionally, we have extended the mutation detection to other members in some
families, including:
18 siblings
11 couples of carriers
3 prenatal diagnosis
The frequency of the F508del mutation in CF alleles was 60.6% (40/66)