24.08.2013 Views

2008 Barcelona - European Society of Human Genetics

2008 Barcelona - European Society of Human Genetics

2008 Barcelona - European Society of Human Genetics

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

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 .

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!