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

Genetic analysis, linkage, and association
During the last 2 years, 67 patients (29 index cases, sporadic and
some familial forms) were entirely tested by DHPLC. 20 index cases
were found mutated with 13 different mutations, 8 of which being
previously reported. DHPLC detected 5 novel mutations believed to
generate AXD as: mutations arose de novo, were absent from healthy
relatives and from 100 control chromosomes, affected a conserved
amino-acid and a functionally important domain, and no other change
was detected. Several prenatal diagnosis have been already carried
out. DHPLC screening for GFAP mutations is confirmed to be a rapid,
sensitive and reliable, cost-effective and high-throughput method for
AXD diagnosis.
P0902. The analysis of Eotaxin (CCL11) gene single nucleotide
polymorphisms in allergic rhinitis patients and healthy donors
from Volga-Ural region of Russia
A. Khuzina 1 , A. Karunas 1 , A. Biktasheva 2 , A. Yuldasheva 3 , E. Etkina 2 , E. Khusnutdinova
1 ;
1 Institute of Biochemistry and Genetics, Ufa, Russian Federation, 2 Bashkir
Medical State University, Ufa, Russian Federation, 3 Pediatric polyclinic N1, Ufa,
Russian Federation.
Allergic rhinitis (AR) is an inflammatory disease of the nasal mucosa
that is characterized by sneezing, nasal congestion, and watery rhinorrhea.
It is the most common form of atopic disease, affecting about
20% population in the world. Eotaxin is believed to play an important
role in AR as a potent chemoattractant and activator of eosinophils and
Th2 lymphocytes.
The purpose of this study was to investigate the allele and genotype
frequencies of two polymorphisms (−384A>G and 67G>A) of the gene
in AR patients and in controls.
The patient group consisted of 285 individuals with allergic rhinitis, the
control group included 169 unrelated non-allergic individuals. Genomic
DNA was extracted from peripheral blood leucocytes by standard phenol/chloroform
method. Genotyping was performed by PCR followed
by restriction digestion.
No significant difference was observed in allele or genotype frequencies
of any SNP between AR patients and controls. The most common
genotype of −384A>G polymorphism was AG, revealed in 48,16% of
patients and in 53,13% of control group . The frequency of GG genotype
was insignificant higher in patient (29%) than in healthy donors
(23%). The GG genotype of 67G>A polymorphism was prevalent in
both groups (65,96% - in the patient, 69,82% - in the control).
Thus, the data of this study has revealed negligible differences in the
distribution of polymorphic alleles and genotypes of the CCL11 gene
between compared groups, but not detected significantly association
of single nucleotide polymorphisms of Eotaxin gene with AR in Volga-
Ural region of Russia .
P0903. Whole-genome association study of Alzheimer’s Disease
using DNA pooling with microarrays
G. Kirov, N. Norton, L. Georgieva, R. Abrams, A. Morgan, V. Moskvina, I. Nikolov,
P. Hollingworth, P. Holmans, M. O’Donovan, J. Williams, M. Owen;
Cardiff University, Cardiff, United Kingdom.
Late-onset Alzheimer’s Disease (LOAD) has a strong genetic component
but the only susceptibility gene definitively identified to date is
APOE. We wanted to identify further susceptibility genes by performing
a whole-genome association study. In order to reduce the cost,
we used a DNA pooling approach. We constructed pools of 1000
LOAD cases and 1200 age- and gender-matched controls. We used
Affymetrix 250K Sty and Nsp SNP genotyping arrays, as well as Illumina
HH300 and HH240S arrays. These assay a total of over 1 million
SNPs, of which 80,000 are represented on both platforms. Depending
on the cost and quality of the hybridisations, we replicated each pool
between 4 and 15 times on each array, and used between 3 and 8 high
quality replicates of each array for analysis. In order to prove that our
experiment is capable of detecting true genetic association, we examined
whether we were able to detect the known association at APOE. 7
SNPs close to APOE showed differences in allele frequencies of >6%,
of which 4 were >10%. This work demonstrated the accuracy of our
pooling method and indicates that we would have easily detected the
association with APOE, in spite of the fact that neither of the two SNPs
that determine the ApoE4 genotype is on the arrays. Two of the four
arrays detected the effect, probably due to the different SNP coverage
and low LD in this region, showing the potential benefit of using all ar-
rays. We are individually genotyping the other promising loci.
P0904. Association of Long Polyglycine Tracts (GGN repeats) in
Exon 1 of the Androgen Receptor Gene with Cryptorchidism and
Penile Hypospadias in Iranian Patients
R. Radpour 1 , M. Rezaee 2 , A. Tavasoly 3 , S. Solati 3 ;
1 Reproductive Biomedicine Research Center of Royan Institute, Tehran, Islamic
Republic of Iran, 2 Avesina Research Institute, Beheshti University, Tehran,
Islamic Republic of Iran, 3 Biomedical Research Center of Military University of
Medical Sciences, Tehran, Islamic Republic of Iran.
Hypospadias and cryptorchidism are the two most common congenital
malformations in males affecting 0.3-0.7% and 2-4%, respectively,
at birth. To study the association of CAG/GGN trinucleotide repeats
in the androgen receptor gene (AR gene) with cryptorchidism and
hypospadias in Iranian population, we performed a comprehensive
case-control study of 76 cryptorchid and 92 hypospadiac (divided into
subgroups of glanular, penile, and penoscrotal hypospadias) Iranian
males. The length of the CAG/GGN repeat segment was evaluated
by using PCR-sequencing in exon 1 of AR gene. To eliminate other
mutations in the AR gene, exons 2-8 of AR gene were screened by
PCR-SSCP. Exclusion of known causes of male infertility was done
by karyotype analysis, Y chromosome microdeletion analysis, cystic
fibrosis transmembrane regulator gene (CFTR) mutation analysis, and
INSL3/LGR8 gene mutation analysis. There were no significant differences
in CAG lengths between the cases and controls but GGN
numbers were found to be significantly higher (median 24 vs. 22)
among both subjects with penile hypospadias (P = 0.018) and those
with a history of cryptorchidism (P = 0.001), compared with controls. In
addition, the GGN numbers among subjects with penile hypospadias
were significantly different, compared with the two other subgroups of
hypospadias (P = 0.001). We were able to identify 12 different CAG
alleles and 8 different GGN alleles in the cryptorchid group. Although
further studies are needed to elucidate the possible role of specific
CAG/GGC combinations, our data suggested the possible association
between polyglycin tract polymorphism in androgen receptor gene and
cryptorchidism.
P0905. Allelic variants of APOA5 and its transcription factor
USF1 predispose to atherogenic dyslipidemia
P. P. Laurila 1 , J. Naukkarinen 1 , P. J. Barter 2 , C. Ehnholm 1 , L. Peltonen 1,3 ;
1 National Public Health Institute of Finland and Department of Medical Genetics,
University of Helsinki, Helsinki, Finland, 2 The Heart Research Institute,
Sydney, Australia, 3 The Broad Institute of MIT and Harvard, Boston, MA, United
States.
Atherogenic dyslipidemia (AD) is a component of the metabolic syndrome,
a well-known cluster of risk-factors for type 2 diabetes. AD is
characterized by abnormally high serum triglyceride and low HDL-cholesterol
levels.
The USF1 transcription factor and apolipoprotein A5 (APOA5) are key
players in lipid metabolism. The two genes operate on the same pathways
with USF1 known to be a major regulator of APOA5. We recently
reported the association of USF1 with FCHL, a common dyslipidemia
predisposing to cardiovascular disease (Pajukanta 2004) and also established
the significance of USF1 in prospective population cohorts
(Komulainen 2006). Multiple studies link plasma levels of APOA5 and
the allelic variants of this gene with elevated plasma triglycerides.
Here we show for the first time that allelic variants of APOA5 (S19W,
-1131T>C, -1464T>C) associate with AD (p=0.009) as well as its
component traits, changes in plasma triglycerides (p=0.00001) and
HDL-cholesterol (p=0.0001) in 130 Australian AD families (n=533). We
observed a dose-dependent association of a common APOA5 haplotype
with elevated triglycerides and decreased HDL-cholesterol. A
protective haplotype was also observed. Conditioning for the carriership
of the APOA5 risk allele, a risk haplotype of USF1 was identified,
in agreement with previous studies. Importantly, individuals carrying
risk haplotypes for both genes had even higher plasma triglyceride
levels than those carrying either APOA5 or USF1 risk haplotype alone
(p=0.001).
We thus hypothesize that the joint effect of risk alleles of APOA5 and
its regulator, USF1, contribute to the pathogenesis of AD and potentially
also to the metabolic syndrome.
2