2008 Barcelona - European Society of Human Genetics
2008 Barcelona - European Society of Human Genetics
2008 Barcelona - European Society of Human Genetics
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Clinical genetics<br />
P01.156<br />
FGFR mutations in turkish patients with craniosynostosis<br />
syndrome by DHPLc<br />
S. Pehlivanoglu1 , E. Mihci2 , H. Kayserili3 , M. O. Caliskan1 , S. Tacoy2 , G. Luleci1<br />
, O. M. Alper1 ;<br />
1Akdeniz University, Faculty <strong>of</strong> Medicine, Department <strong>of</strong> Medical Biology and<br />
<strong>Genetics</strong>, Antalya, Turkey, 2Department <strong>of</strong> Clinical <strong>Genetics</strong>, Antalya, Turkey,<br />
3Istanbul University, Institute <strong>of</strong> Children’s Health, Department <strong>of</strong> Medical <strong>Genetics</strong>,<br />
Istanbul, Turkey.<br />
Fibroblast growth factor receptor 2 (FGFR2) gene mutations have<br />
been associated with the craniosynostotic conditions <strong>of</strong> Apert, Crouzon,<br />
Pfeiffer, Jackson-Weiss, Saethre-Chotzen, Beare-Stevenson<br />
Cutis Gyrata, and Antley-Bixler syndromes in various ethnic groups .<br />
Thirty seven unrelated Turkish patients with Apert syndrome (n=8),<br />
Crouzon syndrome (n=10), Pfeiffer syndrome (n=3), Saethre/Chotzen<br />
syndrome (n=3), and unclassified craniosynostosis (n=13) were<br />
screened for mutations in exons IIIa and IIIc <strong>of</strong> the FGFR2 gene by<br />
polymerase chain reaction, DHPLC and direct sequencing . We established<br />
the optimal denaturing High Performance Liquid Chromatography<br />
(DHPLC) parameters <strong>of</strong> each exons using the WAVE Maker<br />
S<strong>of</strong>tware version 1 .6 .2 . Each anomalous elution peak was then subjected<br />
to direct sequencing . Our DHPLC based protocol enabled us to<br />
identify the causative mutations in most <strong>of</strong> the patients, as following,<br />
seven <strong>of</strong> 8 patients with Apert syndrome (S252W,P253R) and six out<br />
<strong>of</strong> 10 patients with Crouzon syndrome (C278F,Q289P,W290R,C342Y),<br />
two out <strong>of</strong> 3 patients with Pfeiffer syndrome (P253R,C342R) . We did<br />
not detect any FGFR2 gene mutations in patients with Saethre-Chotzen<br />
syndrome or unclassified craniosynostosis patients. The DHPLC<br />
based protocol can be used for an efficient, cost effective and reliable<br />
mutational analysis <strong>of</strong> the FGFR2 gene . In addition, the present<br />
study provides a preliminary data in Turkish population, elucidation <strong>of</strong><br />
the FGFR2 mutations in patients with clinical features suggestive <strong>of</strong><br />
especially Apert, Crouzon and Pfeiffer syndrome <strong>of</strong>fers a significant<br />
benefit to those families in terms <strong>of</strong> genetic counseling and prenatal<br />
diagnosis .<br />
P01.157<br />
Prenatal analysis <strong>of</strong> dwarfism due to mutations in FGFR3 gene<br />
in spanish population<br />
M. Fenollar-Cortés 1 , M. Martínez-García 2,3 , M. Rodríguez de Alba 2,3 , D. Diego-Álvarez<br />
2,3 , I. Lorda-Sánchez 2,3 , R. Cardero 2,3 , C. Ramos 2,3 , C. Ayuso 2,3 , M.<br />
Trujillo-Tiebas 2,3 ;<br />
1 Hospital Clínico San Carlos, Madrid, Spain, 2 Fundación Jiménez Díaz, Madrid,<br />
Spain, 3 Centro de Investigación Biomédica en Red de Enfermedades Raras<br />
(CIBERER), ISCIII, Madrid, Spain.<br />
INTRODUCTION: Thanatophoric dysplasia (TD), achondroplasia<br />
(ACH) and hypochondroplasia (HCH) are skeletal dysplasias with an<br />
autosomal dominant pattern . We present the results <strong>of</strong> FJD skeletal<br />
dysplasias cases over eight years in prenatal and miscarriage samples<br />
studying mutations in the fibroblast growth factor receptor 3 (FGFR3)<br />
gene .<br />
MATERIAL AND METHODS: Fetal DNA was isolated from amniotic<br />
fluids (AF, 15-35 weeks <strong>of</strong> gestation), villi chorionic samples (CVS,<br />
9-20 weeks) and tissue <strong>of</strong> abortion (TA, 15-35 weeks) . All samples<br />
were karyotyped . 5 different PCRs that comprises the more relevant<br />
condons (248, 249, 250, 253, 370, 371, 373, 375, 380, 538, 540, 650<br />
and 807) were analysed by automated sequencing analyser . 30 prenatal<br />
cases were referred to FJD Laboratory: 18 CVS (60%) and 12<br />
AF (40%) .<br />
RESULTS: Of the 18 CVS only 2 were positives, and in both cases the<br />
pregnant women were also affected <strong>of</strong> ACH . Of the 12 AF, we obtained<br />
10 negative cases and 2 TD-I+ . Main referral (75%) was short limbs<br />
and other skeletal anomaly in the present pregnancy . We received 19<br />
TA but only 16 studies because <strong>of</strong> DNA degradated, with the following<br />
results: 1 TD-I; 3 TD-II, 2 aneuploides .<br />
CONCLUSIONS: Molecular analysis <strong>of</strong> CVS in first trimester is useful<br />
when one <strong>of</strong> the parents is affected due to the 50% <strong>of</strong> risk . Only severe<br />
forms (TD) are detected by ultrasound in second trimester . For miscarriages,<br />
is obligatory the fetal karyotype fetal and molecular analysis by<br />
sequencing <strong>of</strong> FGFR3 gene .<br />
P01.158<br />
Postnatal analysis <strong>of</strong> dwarfism due to mutations in FGFR3 gene<br />
in spanish population<br />
M. Trujillo-Tiebas 1,2 , M. Fenollar-Cortés 3 , M. Martínez-García 1,2 , C. Ramos 1,2 ,<br />
J. Gallego-Merlo 1,2 , F. Infantes 1,2 , M. Rodríguez de Alba 1,2 , I. Lorda-Sánchez 1,2 ,<br />
C. Ayuso 1,2 ;<br />
1 Fundación Jiménez Díaz, Madrid, Spain, 2 Centro de Investigación Biomédica<br />
en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain, 3 Hospital<br />
Clínico San Carlos, Madrid, Spain.<br />
Introduction: Achondroplasia (ACH), the most common form <strong>of</strong> human<br />
dwarfism (1/10.000-30.000 births), and hypochondroplasia (HCH), a<br />
less severe and less frequent condition (1/50 .000 births), are inherited<br />
in an autosomal dominant manner as other lethal skeletal dysplasias<br />
(Thanatophoric dysplasia (TD) type I and II) . Mutations in the gene <strong>of</strong><br />
fibroblast growth factor receptor 3 (FGFR3) are known responsible for<br />
them .<br />
We present the results about this disorders gather in eight years in our<br />
hospital from different geographical origins <strong>of</strong> Spain .<br />
Material and Methos: Patients were all postnatal (neonatal, child and<br />
adult people) with a wide range <strong>of</strong> age . DNA was isolated from blood<br />
leucocytes or mouth epithelial cells . 5 different PCRs that comprise the<br />
more relevant codons (248, 249, 250, 370, 371, 373, 375, 380, 540,<br />
650 and 807) were analysed by automated sequencing analyser . We<br />
also detected the most frequent mutation R380G in ACH phenotype by<br />
SNAPSHOT technology .<br />
Results: From 77 cases, we obtained 26 ACH+ (33 .8%); 7 HCH+<br />
(9 .1%) and 1 TD type I+ (1 .3%) . We found 5 cases with a polymorphic<br />
allele (F384L) and 3 cases with a polymorphic allele (G549G) very<br />
close to the splice site .<br />
Cconclusions: Our strategy for studying all samples is always the<br />
same independently the clinical suspicion . Sequencing FGFR3 is a<br />
good practice to detect known and new mutations in individuals affected<br />
with different skeletetal dysplasias, especially when few clinical<br />
findings are added to the application.<br />
P01.159<br />
Functional analysis <strong>of</strong> osteoporosis pseudoglioma associated<br />
missense mutations in LRP<br />
A. Saarinen 1,2 , U. Lahtinen 1,3 , A. Lehesjoki 1,3 , O. Mäkitie 1,4 ;<br />
1 Folkhälsan Institute <strong>of</strong> <strong>Genetics</strong>, Biomedicum Helsinki, Helsinki, Finland, 2 Department<br />
<strong>of</strong> Medical <strong>Genetics</strong>, University <strong>of</strong> Helsinki, Helsinki, Finland, 3 Neuroscience<br />
Center, University <strong>of</strong> Helsinki, Helsinki, Finland, 4 Metabolic Bone Clinic,<br />
Hospital for Children and Adolescents, Helsinki University Hospital, Helsinki,<br />
Finland.<br />
Background: Mutations in the low density lipoprotein receptor-related<br />
protein 5 gene (LRP5) have been associated with high and low bone<br />
mass . While homozygous LRP5 mutations cause osteoporosis-pseudoglioma<br />
syndrome (OPPG), characterized by severe osteoporosis<br />
and blindness, heterozygous mutations have been associated with reduced<br />
bone mass . LRP5 functions as a plasma membrane receptor in<br />
the Wnt signaling pathway . We previously described LRP5 mutations<br />
in patients with OPPG and/or severe osteoporosis . In this study we<br />
further analyzed the role <strong>of</strong> these mutations in Wnt signal transduction<br />
and cellular localization .<br />
methods: Mutations were introduced to full length human LRP5-pcD-<br />
NA3 .1 expression vector using site-directed mutagenesis . Wnt signal<br />
transduction assays were performed in 293HEK cells using a previously<br />
published Wnt-induced canonical signaling assay (Ai etal . 2005) .<br />
Localization studies were performed in COS-1 cells using immun<strong>of</strong>luorescence<br />
staining .<br />
Results: Three different missense mutations were identified and selected<br />
for further studies . Wnt signaling assays indicated that one <strong>of</strong> the<br />
mutations, R570W in exon 8, completely disrupted Wnt signal transduction<br />
. The second mutation, R1036Q in exon 14, resulted in partial<br />
disruption <strong>of</strong> Wnt signaling while the third mutation, R925C in exon 12,<br />
did not show any alteration in the signaling assays . Localization studies<br />
revealed that the R1036Q and R925C mutant proteins were able to<br />
reach plasma membrane where as the R570W could not be detected,<br />
suggesting that it might be post-translationally degraded .<br />
conclusions: We were able to show that some LRP5 mutations directly<br />
impair Wnt signal transduction and cellular transportation while<br />
other pathogenetic mechanisms are associated with some mutations .