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

Prenatal diagnosis
P0471. Preimplantation Genetic Diagnosis for a Y-autosome
translocation t(Y;8)(p11;q11).
P. Gosset 1 , M. Schillinger 1 , C. Schluth 1 , Y. Menezo 2 , B. De Fréminville 3 , S.
Viville 1 ;
1 Laboratoire de Biologie de la Reproduction, CHU Strasbourg, SIHCUS-CMCO,
Schiltigheim, France, 2 Assistance Médicale à la Procréation, Laboratoire Marcel
Mérieux, Lyon, France, 3 Service de Génétique Clinique, Chromosomique et
Moléculaire, CHU Nord, Saint Etienne, France.
Reciprocal Y-autosome translocations are rarely observed, because
implication of the Y chromosome in a translocation produces, most of
the time, a meiosis blockage, which results in azoospermia.
However, when some spermatozoa are observed, assisted reproductive
techniques (ART), particularly intra-cytoplasmic sperm injection
(ICSI), can be proposed.
Because of the translocation, some of the spermatozoa may carry an
abnormal chromosomal complement, involving a risk to obtain embryos
with unbalanced karyotype. Preimplantation Genetic Diagnosis
(PGD) can prevent this by selecting balanced embryos before transfer
to the mother’s uterus.
We present here a patient, carrying a t(Y;8)(p11;q11) translocation,
who was referred to us for a PGD.
Because of the lack of data about segregation in Y-autosome translocations,
analysis of patient’s spermatozoa was performed by Fluorescent
in situ Hybridisation (FISH) to estimate the risk of missegregation.
Simultaneously, to prepare for PGD, the FISH diagnosis method on
single cell was improved by using a set of 4 probes: X centromere
and Y heterochromatin labelled with Tetramethyl-Rhodamine, 8qtel labelled
with dGreen, 8 centromere labelled with Spectrum Aqua.
Over 500 spermatozoa scored, 41.6% were found to be balanced. A
PGD cycle was started, but diagnosis was not performed because of
embryos development arrest at day 2.
Prior to any PGD attempt in such difficult cases, study of the chromosomal
segregation establishes the proportion of balanced gametes,
allowing to estimate chances of a successful ART. If too low, patients
must be offered alternative options such as sperm donation.
P0472. A one year experience on PGD at Ege University in Izmir/
Turkey
E. Karaca 1 , C. Gunduz 2 , G. Altin 3 , T. Cankaya 1 , B. Durmaz 1 , E. Tavmergen 3 , E.
Tavmergen Goker 3 , H. Akin 1 , O. Cogulu 1 , F. Ozkinay 1 ;
1 Ege University Faculty of Medicine Department of Medical Genetic, Izmir, Turkey,
2 Ege University Faculty of Medicine Department of Medical Biology, Izmir,
Turkey, 3 Ege University Faculty of Medicine Department of Family Planning and
Infertility Research and Treatment Center, Izmir, Turkey.
We would like to present our preliminary report of 1 year experience.
Couples applied to the Family Planning and Infertility Research and
Treatment Center for assisted reproductive technologies (ART) were
referred to Medical Genetics Department for PGD and aneuploidy
screening due to advanced maternal age, recurrent miscarriage, recurrent
ART failure and balanced translocation carriers between the
period of January 2006 and January 2007.
One or two blastomeres were aspirated on day 3 and analyzed using
the fluorescent in situ hybridization (FISH) technique. Probes for
chromosomes 13,16,18,21 and 22 were used for aneuploidy screening
and individual specific probes were chosen for chromosomal translocations.
Unaffected embryos were transferred on day 4 or 5.
There were 20 cycles for aneuploid screening (group 1) and 2 cycles
for chromosomal translocation (group 2). In group 1, 118 embryos
were biopsied successfully with a diagnosis rate of 84% and 39 unaffected
embryos were transferred in 20 cycles, achieving 10 singleton
pregnancies (implantation rate: 50%). In group 2, 8 embryos were biopsied
with a diagnosis rate of 84% in 2 cycles and 1 balanced embryo
transferred achieving pregnancy. Unfortunately we could not find any
balanced embryo in the other cycle of our translocation group and cancelled
the transfer. All antenatal amniocentesis confirmed the diagnosis.
Post-natal physical examination showed no evidence of major abnormalities.
PGD is an alternative method for having healthy children
in selected couples with chromosomal abnormalities. In addition, PGD
may increase the implantation rate in infertile couples and balanced
translocation carreers seeking ART assistance.
P0473. Pre-implantation Genetic Diagnosis (PGD) for Genetic
and Metabolic Disorders in Saudi Arabia
A. I. Al-Aqeel 1 , S. Coskun 2 ;
1 Riyadh Military Hospital/ King Faisal Specialist Hospital and Research Centre,
Riyadh, Saudi Arabia, 2 King Faisal Specialist Hospital and Research Centre,
Riyadh, Saudi Arabia.
Saudi Arabian culture is highly consanguineous, with cousin marriages
accounting for 60-70%. Given the difficulties in management of genetic
disorders, preventive measures for the suffering families by doing
pre-implantation genetic diagnosis is undertaken. Over 30 cases are
successfully prevented by PGD. The first of these disorders is Sanjad-Sakati
Syndrome (SSS) OMIM# 24140, which is characterized
by hypoparathyroidism, growth and mental retardation with a unique
12bp deletion. The second is Niemann Pick Disease type B (NPD-B)
OMIM# 257200,) (acid sphingomylinase (ASM) deficiency) with more
than 70 mutations reported in (SMPD1) gene, which presents with severe
phenotype in Saudi Arabia. Four unique mutations are found in
our Saudi families. A family with (W533R) mutation in the (SPMDI)
gene suffering from a severe phenotype underwent PGD. The third
disorder is Morquio’s disease (MPSIV) OMIM # 253000, with severe
classic phenotype with N-acetyl galactosamine-6-sulftase deficiency
(MPSIV-A). More than 20 different mutations in (GALNS) gene reported
in (MPSIV-A). A family with three affected siblings with severe
classic (MPIV-A) with detected W195C mutation in the (GALNS) gene
underwent PGD. In all these families PGD was undertaken using fluorescent
PCR(F-PCR) and/or nested PCR with sequencing on a single
cell, or Multiple Displacement Modification (MDA) to amplify the whole
genome from a single cell. A singleton pregnancy ensure after transfer
of one heterozygous and one/or normal embryo and prenatal diagnosis
by CVS confirmed a normal pregnancy. This is the first report of
successful PGD in different genetic disorders in Saudi Arabia, and the
Muslim world.
P0474. QF-PCR: reliable and accurate for the rapid detection of
the most common fetal chromosomal abnormalities in the first
trimester
G. Christopoulou, A. Hatzaki, S. Christopoulou, A. Hatzipouliou, J. Donoghue,
M. Karkaletsi, V. Velissariou;
Mitera Maternity & Surgical Center, Cytogenetics and Molecular Biology lab,
Athens, Greece.
Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) is a
well established method for the rapid prenatal diagnosis of the most
common chromosomal aneuploidies found in amniotic fluid samples.
In recent years it has also been applied to chorionic villi samples (CVS)
in the first trimester.
Since June 2005 to date 1272 CVS samples were tested with QF-PCR
in our lab for the diagnosis of aneuploidies involving chromosomes 13,
18, 21 and X, Y. A total of 38/1272 (3%) fetal aneuploidies were detected
and confirmed after chromosomal analysis of long-term cultures
(LTC). Twenty four cases with trisomy 21 (1 mosaic case), 10 cases
with trisomy 18, 1 case with trisomy 13, 1 case with Klinefelter, 1 case
with triploidy and 1 case of a mosaic sex chromosome abnormality
were detected. Maternal contamination was detected in 5/1272 (0,4%)
samples and therefore no QF-PCR results were obtained. No falsepositive
or false-negative results were reported for the chromosomes
tested. LTC analysis revealed an abnormal result for chromosomes
not tested for by QF-PCR in 11/1272 (0,8%) cases. In another 5 (0,4%)
cases there was a discrepancy between QF-PCR and LTC analysis
due to in situ placenta abnormalities missed by sampling.
Based on our experience of two years, we consider QF-PCR to be a
reliable, accurate, easy and relatively inexpensive method for rapid
prenatal diagnosis in first trimester CVS.
P0475. Application of genetic methods in Prenatal Diagnosis:
Experience in Iran
F. Mahjoubi 1 , M. Akbary 2 ;
1 NRCGEB, tehran, Islamic Republic of Iran, 2 Akbary Laboratory of Medical Genetics,
Taleganee Ave., Tehran, Iran& Clinical Genetic Dept. Tarbiat Modaress
University, Tehran, Iran, tehran, Islamic Republic of Iran.
Prenatal diagnosis has revolutionized prenatal care from the perspective
of both the patient and the physician. For the patient, prenatal diagnosis
provides genetic, anatomic, and physiologic information about
the fetus or fetuses. The information can help individual to make deci-
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