2008 Barcelona - European Society of Human Genetics
2008 Barcelona - European Society of Human Genetics
2008 Barcelona - European Society of Human Genetics
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Cytogenetics<br />
P02.096<br />
Delineation <strong>of</strong> a critical Region on chromosome 18 for the<br />
del(18)(q12.2q21.1) syndrome<br />
K. Buysse 1 , B. Menten 1 , A. Oostra 2 , S. Tavernier 3 , G. R. Mortier 1 , F. Speleman 1 ;<br />
1 Center for Medical <strong>Genetics</strong>, Ghent University Hospital, Ghent, Belgium, 2 Center<br />
for Developmental Disorders, Ghent University Hospital, Ghent, Belgium,<br />
3 M.P.I.G.O. ‘t Vurstjen, Evergem, Belgium.<br />
Array CGH has been instrumental in the identification <strong>of</strong> submicroscopic<br />
chromosomal aberrations leading to mental retardation and congenital<br />
abnormalities (MR/MCA), the delineation <strong>of</strong> new microdeletion<br />
syndromes and the identification <strong>of</strong> genes implicated in MR/MCA syndromes<br />
. An important step prior to assigning particular phenotypic features<br />
to particular genes is the delineation <strong>of</strong> critical regions for these<br />
specific clinical features. To this purpose, smaller interstitial deletions<br />
can be particularly important. In some syndromes, haploinsufficiency<br />
<strong>of</strong> a single gene appears to be responsible for most <strong>of</strong> the phenotypic<br />
features, as is the case for the EHMT1 gene in the 9q34 subtelomeric<br />
deletion syndrome . In contrast to distal 18q deletions, proximal interstitial<br />
deletions encompassing chromosome band 18q12 .3 and parts <strong>of</strong><br />
neighboring bands (q12.2→q21.1) have been reported less frequently.<br />
Up to now, 24 patients carrying such deletions were described . Accurate<br />
genotype-phenotype correlations are only possible for those<br />
cases for which breakpoints have been molecularly defined.<br />
Here we describe a boy with a submicroscopic deletion <strong>of</strong> less than 1 .8<br />
Mb <strong>of</strong> subband 18q12 .3 . The phenotypic features <strong>of</strong> the proband correspond<br />
well with those observed in patients with larger cytogenetically<br />
detectable deletions encompassing chromosome band 18q12 .3 . The<br />
deletion has been characterized at the molecular level which is important<br />
for defining small regions and eventually specific genes associated<br />
with specific phenotypic features. The deletion enabled us to define<br />
a critical region for the following features <strong>of</strong> the del(18)(q12 .2q21 .1)<br />
syndrome: hypotonia, expressive language delay, short stature and<br />
behavioral problems .<br />
P02.097<br />
A novel sex determining locus in a 46,XX-sRY negative sex<br />
reversal patient carrying a t(8;19)(q22.1;q13.1)<br />
N. Najera, J. Berumen, S. K<strong>of</strong>man, J. Perez, G. Queipo;<br />
Hospital General de Mexico/Facultad de Medicina, Mexico City, Mexico.<br />
The sex determining genes SRY and SOX9 are required to initiate<br />
and maintain testicular development . However, genetic interactions<br />
controlling the earliest steps in gonadal development remain poorly<br />
understood . The molecular abnormalities underlying a high proportion<br />
<strong>of</strong> XX maleness remain undiscovered . Using <strong>of</strong> high density SNP array<br />
in sex reversal patients could be useful to characterize the etiology<br />
<strong>of</strong> the abnormal gonadal development and provide new molecular<br />
insights into the normal regulatory network in the testis and ovary<br />
development . We performed SNPs microarray genotyping (Affymetrix<br />
geneChip 500k) to investigate homozygosity mapping and LOH in a<br />
nuclear family (mother, father, siblings) <strong>of</strong> a 46,XX-SRY negative male<br />
carrying a t(8;19)(q22 .1;q13 .1) . In addition we analyzed 10 sporadic<br />
SRY negative XX male . The results were also compared with the International<br />
HapMap . The analysis <strong>of</strong> the break points in the patient<br />
revealed in chromosome 19 three intervals with 59, 89, 25 and 15<br />
homozygous SNPs and three regions containing 83, 73 and 57 LOH<br />
SNPs located in chromosome 8 . Analysis <strong>of</strong> the data revealed four sex<br />
determining genes candidates, we present and discuss the genomic<br />
data and the analysis performed in order to identify a novel locus involved<br />
in the testicular development in humans .<br />
P02.098<br />
Prenatally diagnosed recombinant <strong>of</strong>fsprings resulting from<br />
adjacent-1, adjacent-2, 3:1 segregation modes <strong>of</strong> reciprocal<br />
translocations:fish and cytogenetic studies<br />
O. Sezer, F. Ekici, B. Ozyilmaz, M. Tosun, M. Ceyhan, O. Aydın, I. Kocak, G.<br />
Ogur;<br />
Ondokuz Mayis University Medical Faculty, Samsun, Turkey.<br />
Balanced translocation carriers can have recombinant <strong>of</strong>fsprings due<br />
to adjacent-1, adjacent-2, 3:1 and 4:0 segregation modes . Here, we<br />
report three prenatally diagnosed recombinant fetuses resulting from<br />
balanced parental translocations .<br />
Case1:Amniocentesis was performed because <strong>of</strong> bilateral choroid<br />
plexus cysts and hyperechogenic bowel . Fetal karyotype showed a de-<br />
rivative chromosome 1p[46,XY,der(1)t(1;?)(p36,1;?)] which was paternally<br />
originated:46,XY,t(1;8) (p36,1;p21,3)]. FISH confirmed translocation<br />
between chromosomes 1 and 8; fetal karyotype was interpreted as<br />
partial monosomy 1p/partial trisomy 8p . Adjacent-1 segregation mode<br />
was suggested . Parents decided to terminate the pregnancy . Fetus<br />
presented facial dysmorphism, limb abnormalities, cerebellar hypoplasia,<br />
ventriculomegaly, bilateral choroid plexus cysts, lung defects .<br />
Case2:Amniocentesis was performed due to fetal abnormalities: cleft<br />
lip/palate, tetralogy <strong>of</strong> fallot, ASD, single artery/vein <strong>of</strong> umbilical cord .<br />
Cytogenetics revealed unbalanced chromosomal translocation:46,XY,<br />
der(15)t(10;15) (q22,2;q11,2), paternally derived [46,XY,t(10;15)(q22,2<br />
;q11,2)] . Adjacent-2 segregation mode was suggested . FISH analysis<br />
confirmed der(15)t(10;15). Pregnancy ended spontaneously after amniocentesis<br />
. The fetus couldn’t be investigated .<br />
Case3:Amniocentesis was performed because <strong>of</strong> positive maternal<br />
serum triple screening . Cytogenetics revealed a surnumerary<br />
chromosome(47,XY,+mar) . Parents were karyotyped . The mother<br />
showed balanced reciprocal translocation:t(2;14)(p23;q23) . Surnumerary<br />
chromosome was identified as part <strong>of</strong> chromosome 14 (FISH<br />
analysis) . Fetal karyotype was interpreted as:47,XY,+der(14)t(2;14)(p<br />
23;q23)mat; partial trisomy 2p/partial trisomy 14q due to 3:1 segregation<br />
was suggested . Pregnancy was terminated . Extensive clinical<br />
evaluation showed fetal dysmorphism and open cranial sutures .<br />
P02.099<br />
male pseudohermaphroditism: a case report<br />
N. Andreescu, V. Belengeanu, D. Stoicanescu, S. Farcas, C. Popa, M. Stoian;<br />
University <strong>of</strong> Medicine and Pharmacy “Victor Babes”, Timisoara, Romania.<br />
Male pseudohermaphroditism is characterized by the presence <strong>of</strong> 46,<br />
XY karyotype, exclusively male gonads and ambiguous or female external<br />
and/or internal genitalia, caused by incomplete virilization during<br />
prenatal life . We report the case <strong>of</strong> an infant, in whom physical<br />
examination showed ambiguous external genitalia and some dysmorphic<br />
features . Cytogenetic investigation was performed for the correct<br />
assignment <strong>of</strong> the gender and chromosome analysis in blood lymphocytes<br />
revealed male genetic sex . The ambivalent aspect <strong>of</strong> the external<br />
genitalia, the gonads that are exclusively testes together with<br />
the result <strong>of</strong> the cytogenetic analysis showing male genetic sex, led<br />
to the diagnosis <strong>of</strong> male pseudohermaphroditism . A multidisciplinary<br />
approach involving pediatricians, specialists in the field <strong>of</strong> endocrinology,<br />
genetics, surgery and psychiatry is necessary in order to reach<br />
a prompt and correct diagnosis and treatment . In conclusion, careful<br />
examination <strong>of</strong> the external genitalia <strong>of</strong> every newborn should be systematic<br />
. Early diagnosis <strong>of</strong> a disorder <strong>of</strong> sexual development is <strong>of</strong> great<br />
importance as is the appropriate gender assignment . The most important<br />
decision will be the choice <strong>of</strong> sex assignment, which will depend<br />
on many complex factors . Birth registration should be postponed until<br />
the diagnostic evaluation enables the most appropriate choice <strong>of</strong> sex<br />
for rearing . The clinical management will help the child and the family<br />
deal effectively with this disorder .<br />
P02.100<br />
PcR based technique for sex selection in cattle<br />
E. Arbabai1 , F. Mahjoubi1 , M. Eskandainasab2 , M. Montazeri1 ;<br />
1 2 NRCGEB, Tehran, Islamic Republic <strong>of</strong> Iran, Zanjan university, Tehran, Islamic<br />
Republic <strong>of</strong> Iran.<br />
Embryo sexing is an important way for sex selection <strong>of</strong> <strong>of</strong>fspring . This<br />
is a potential method to considerably improve animal breeding and the<br />
efficiency <strong>of</strong> dairy and meat production. A novel repeated sequence<br />
specific to male cattle has been identified and named S4. S4 is a 1/5<br />
Kb repeating unit and which also contains various internal repeated<br />
sequence . S4 is localized on the long arm <strong>of</strong> the Y chromosome in the<br />
region <strong>of</strong> ZFY genes .<br />
Aim: The objective <strong>of</strong> this study is to identify embryo sexing by a simple<br />
and precise PCR method .<br />
Materials and Methods: Genomic DNA was extracted from the whole<br />
blood samples. Two sets <strong>of</strong> specific primers were designed<br />
Result: By this PCR based methods we could differentiate between<br />
female and male genomic DNA .<br />
Discussion: With this technique we can distinct males from females .<br />
This method has the potential to be employed for embryonic sex selection<br />
.