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

Cytogenetics
25 patients of this study, an abnormal karyotype had been previously
identified.
We used the 1Mb BAC and PAC Array (VIB Leuven), six patients were
analysed by experiment using a triangle testing. The data were analysed
with the arrayCGHbase software provided by J.Vermeesch.
Results : Copy number variants (CNV) were found in 45% of patients :
24 known and 7 not yet described.
Array-CGH confirmed and mapped the unbalanced karyotype rearrangements
in all the 25 patients with known cytogenetic abnormality.
For two of these patients, additional deletions and duplications
improved the cytogenetic analysis and therefore modified the genetic
counselling.
Among the 75 left MCA/MR patients : Two had large deletions and one
had a large duplication involving homogeneously R-stained regions
regarding 1p (3.2Mb), 10q (2.2Mb) and 11q (1.5Mb) loci. Nineteen patients
had rearrangements involving a single BAC or PAC clone.
For three cases, the mother became pregnant during the study and a
prenatal diagnosis could be proposed. These results will be reported
and discussed with the clinical data.
Grant : AOL 2003-2005 - PHRC 2005 CHU Reims
P0294. Array-CGH characterization of familial and de novo
“apparently balanced” translocations in patients with abnormal
phenotype
C. Sismani 1 , S. Kitsiou-Tzeli 2 , M. Ioannides 1 , V. Anastasiadou 3 , G. Stylianidou 3 ,
E. Papadopoulou 4 , Z. Kosmaidou 5 , E. Kanavakis 2 , A. Kolialexi 2 , A. Mavrou 2 , P.
C. Patsalis 1 ;
1 The Cyprus Institute of Neurology and Genetics, Department of Cytogenetics,
Nicosia, Cyprus, 2 Aghia Sophia Childrens Hospital, University of Athens,
Choremio Laboratory, Athens, Greece, 3 Arch Makarios III Hospital, Department
of Paediatrics, Nicosia, Cyprus, 4 University Hospital Of Heraklion, Department
of Paediatrics, Heraklion, Greece, 5 Alexandra Hospital, Department of Genetics,
Athens, Greece.
We have applied 1Mb resolution array-CGH to investigate 12 cases
of “apparently balanced” translocations in patients with mental retardation
and congenital malformations. Six cases were de novo and
six familial. In the familial cases the patients had an abnormal phenotype
but their karyotype appeared identical to other phenotypically
normal translocation carriers of the family. Chromosomal and various
FISH analyses suggested that the rearrangements were “truly balanced”
in all patients. Array-CGH however, revealed cryptic genomic
imbalances in three cases (25%), two de novo and one familial. All
array-CGH findings were confirmed by FISH. The nature and type of
abnormalities differed among the three cases. In the first case a de
novo t(9;15)(q31;q26), a complex rearrangement was identified involving
a ~6.1Mb duplication on chromosome 9, a ~10Mb deletion and an
inversion on chromosome 15. These imbalances were near but not
directly associated with the translocation breakpoints. In the second
case a de novo t(4;9)(q26;p24), a ~6.6Mb deletion was identified on
chromosome 7 which is unrelated to the translocation. In the third
case (t(4;7)(q21;p15)-familial), a ~4.3Mb and a ~2.3Mb deletions were
found at the translocation breakpoints. In the remaining cases the
translocations appeared balanced at 1Mb resolution. This study provides
additional evidence that cryptic genomic imbalances are common
in patients with abnormal phenotype and “apparently balanced”
translocations not only in de novo but also in familial cases. The use
of microarrays with higher resolution such as high-density oligo-arrays
may reveal that the frequency of cryptic genomic imbalances among
these patients is even higher.
P0295. Effect of borax to human chromosome abnormalities
M. Pongsavee;
Faculty of Allied Health Sciences, Patumthani, Thailand.
The effect of borax to human chromosome abnormalities was analysed
in this study. Borax is a form of boron compound. The chemical
name of borax is sodium borate. Borax is toxic for the somatic cells
and may cause abnormal human genetic materials. Venous blood from
30 male students in Thammasat University (age 18 - 25 years) were
collected to do lymphocyte cell culture. This experiment was divided
into two groups, the first group was the control group and the second
group was the experimental group. The lymphocyte cells in the control
group were cultured without borax. The experimental group was divided
into four sub-groups. The lymphocyte cells in each experimental
100
sub-groups were cultured with different borax concentration (0.1 mg/
ml, 0.15 mg/ml, 0.2 mg/ml and 0.3 mg/ml respectively). Human chromosomes
were studied for abnormalities through Giemsa-staining and
G-banding. The results show that the number of metaphase chromosomes
are reduced when lymphocyte cells are cultured with 0.15 mg/
ml (57.22 %), 0.2 mg/ml (50.84%) and 0.3 mg/ml (42.27%) borax concentration.
The results show statistically significant difference between
control and experimental sub-groups (P