2008 Barcelona - European Society of Human Genetics

Cytogenetics
P02.210
clinical features of a case with trisomy 10q and monosomy 3p
resulting from a maternal balance translocation: A case report
and review of clinical features
F. Mahjoubi 1 , M. Akbary 2 , S. Kareeme 3 , G. Babanohammadi 3 ;
1 NIGEB, Tehran, Islamic Republic of Iran, 2 Medical Genetic Dept., Tarbiat
Modaress University, Tehran, Iran, Tehran, Islamic Republic of Iran, 3 Tehran
Medical Genetic Laboratory, Taleganee St, Tehran, Iran, Tehran, Islamic Republic
of Iran.
Here we describe clinical and cytogenteic data on 2 year female child
with partial trisomy for the distal part of the long arm of chromosome
10 (10q22-->qter) and a concomitant monosomy 3(p25-->pter) as a
result of a maternal balanced reciprocal translocation . Her karyotype
was ascertained as 46,XX,der(3)t(3;10)(p25;q22) . The father had normal
karyotype . The mother had an apparently balanced translocation
involving chromosome 3 and 10 [46,XX,t(3;10)(p25;q22)] . To our best
knowledge, this is the second reported case of partial trisomy 10q and
partial trisomy 3p and first reported case from Iran. Clinical features of
this case and a few published cases will be reviewed briefly.
P02.211
Partial duplication of chromosome 16p: narrowing of the critical
region responsible for the common phenotype
G. Marangi 1 , D. Orteschi 1 , M. E. Grimaldi 1 , R. Lecce 1 , V. Leuzzi 2 , G. Neri 1 , M.
Zollino 1 ;
1 Institute of Medical Genetics, Università Cattolica del Sacro Cuore, Roma,
Italy, 2 Department of Child Neuropsychiatry, Università “La Sapienza”, Roma,
Italy.
Clinical descriptions of almost 50 patients with trisomy 16p, encompassing
the band 16p13 .3, have been reported to date in literature .
Phenotypical features commonly associated to this chromosomal alteration
are: severe developmental delay/psychomotor retardation,
growth retardation, seizures, microcephaly, cleft palate, mild flexion
contractures, clubbed feet, genitourinary abnormalities, congenital
heart defects, a specific facial appearance and, usually, a poor prognosis
.
We report the case of a female patient (aged 16 years) with moderate
to severe mental retardation in which we disclosed, by the means of
array-CGH (BAC-array at a resolution of 1 Mb) a cryptic tandem duplication
of chromosomal region 16p13 .3, sized about 2 Mb .
The main clinical features were: psychomotor retardation, very limited
speech, relative microcephaly, narrow forehead, deep set eyes, narrow
palpebral fissures, wide nasal bridge, long philtrum, rounded nasal
tip, thin upper lip, midfacial hypoplasia, a protruding mandible, dysmorphic
and low-set ears, tapering fingers, clubbed feet. The patient never
had seizures .
Our patient’s duplication is the smallest one reported to date with clinical
features that resemble very closely the characteristics of larger
16p trisomy cases . We highlight, however, the relative mildness of our
patient’s phenotype .
We suggest that genes included in this 2 Mb region on 16p13 .3 should
be responsible of the main pathological findings of “trisomy 16p syndrome”,
such as mental retardation, typical facial appearance, microcephaly,
hands and feet abnormalities .
Remarks about the possible causative role of different gene mapped
in the region and comparisons with other microduplication phenotypes
mapped on other regions on chromosome 16p are made .
P02.212
Prenatal findings: a foetus with trisomy of 22 chromosome
B. Aleksiūnienė 1,2 , N. Krasovskaja 2 , V. Kučinskas 1,2 ;
1 Department of Human and Medical Genetics, Medical Faculty of Vilnius University,
Vilnius, Lithuania, 2 Center for Medical Genetics, Vilnius University Hospital
Santariškių Klinikos, Vilnius, Lithuania.
Trisomy of chromosome 22 is very rare chromosomal pathology, particularly
in the second or third trimester of pregnancy . We present a 33year
old para I, gravida IV woman . She was consulted at 12 weeks of
gestation due to aggravated obstetric history . Her previous pregnancy
was terminated at 19 weeks of gestation due to fetal meningocele . After
three years patient delivered a normal boy . The recurrent risk for
meningocele was about 2% . For other congenital malformations risk
was the same as population risk . Fetal NT and maternal serum biochemistry
(PAPP-A and β-hCG) was assessed at 12 weeks of gesta-
tion . NT thickness was 2,92 mm (1,95 MoM), PAPP-A was 0,31 MoM
and β-hCG was 0,6 MoM. The combined risk for trisomy 21 was >1:50
and for trisomy 18-1:61 . The ultrasound scan at 16 weeks showed
asymmetrical fetal growth restriction and congenital heart disease -
tricuspid valve atresia, pulmonary atresia, hypoplastic right ventricle .
The parents opted for termination of pregnancy at 20 weeks of gestation
.
The amniocentesis was performed for quantitative fluorescent polymerase
chain reaction and karyotype analysis . QF-PCR tests results
were negative for chromosomes 13, 18 and 21 trisomies . Chromosome
analysis of lymphocytes revealed 47,XY,+22 karyotype . Fluorescent
in situ hybridization (FISH) was performed using microdeletion
probe localized to 22q11.2. FISH analysis confirmed the trisomy
of chromosome 22 in the proposita . In view of these results parental
chromosome analysis was not requested .
P02.213
complete trisomy 5p due to paternal transmission of
chromosome 5 centric fission products
G. Kalnberza, I. Teilane, Z. Krumina, A. Dzalbs, R. Lugovska;
Medical Genetics Clinic, University Children`s Hospital, Riga, Latvia.
In humans stable centric fission of chromosomes are rare event, and
only few families are reported with this chromosomal aberration . To our
opinion this is the first report of centric fission of chromosome 5 in several
generations . Complete trisomy 5p also is very rare chromosomal
abnormality. Clinical findings of trisomy 5p are macrocephaly, facial dysmorfism,
hypotonia, tracheobronchial abnormalities and heart defects.
We describe a newborn boy was born in 40 weeks of gestation from the
third pregnancy as second child in the family. The first child was healthy
girl, and the second pregnancy ended with spontaneous abortion during
10 weeks of gestation . Birth weight was 3700 g, height 54 cm, HC - 40
cm. After delivery hypotonia, some respiratory difficulties, cephalohaematoma
in parietooccipital region were observed . All sutures of head
were widely opened . Phenotypicaly the patient had low situated ears,
short palpebral fissures, a single crease. The patient died from respiratory
infection at 5 month .
Routine chromosome analyses (GTG-banding) were performed on
peripheral blood lymphocytes of proband, his parents and grandparents
. The karyotype of proband showed complete telocentric trisomy
5p: 47,XY,+der(5)(pter→p10:). The cytogenetic analyses of father and
his mother (proband’s grandmother) revealed centric fission of chromosome
5, thus the karyotypes was 47,XY,-5,+fis(5)(p10),+fis(5)(q10) and
47,XX,-5,+fis(5)(p10),+fis(5)(q10), respectively.
P02.214
Atypical turner syndrome due to structural chromosomal
rearrangements - clinical and cytogenetic study of 9 patients
I. C. Ivanov 1 , C. Rusu 2 , M. Volosciuc 2 , M. Gramescu 2 , V. E. Gorduza 2 , R.
Popescu 3 , C. Bujoran 3 , L. Negura 1 , E. Carasevici 1 , M. Covic 2 ;
1 Immunology and Genetics Laboratory-St Spiridon Hospital, iasi, Romania,
2 (2) University of Medicine and Pharmacy, Medical Genetics Department, iasi,
Romania, 3 (3) Sf Maria Children’s Hospital - Medical Genetics Center, iasi,
Romania.
Turner’s syndrome is the most common chromosomal abnormality in
females, affecting 1:2,500 live female births . It is due to the total or
partial absence of an X chromosome in a female . The most consistent
clinical features are short stature and ovarian failure . A variety of chromosomal
abnormalities are associated with Turner syndrome .
We present the cases diagnosed in Iasi Medical Genetics Center between
2000-2008 with atypical Turner syndrome due to structural chromosomal
rearrangements, in order to discuss cytogenetic diversity of
Turner syndrome . Cytogenetic study was performed using peripheral
lymphocytes with G banding .
Between 2000-2008, our Cytogenetics lab has performed 1380 karyotypes,
27 being recorded with the diagnosis of Turner syndrome . Out of
these, 9(33 .3%) were due to structural chromosomal rearrangements .
Abnormalities identified were: iXq ( 7cases) and r(X) (2cases).
Clinical and cytogenetic data are compared with literature data for
each case . Typical and particular features are discussed .
In conclusion, we present 9 cases diagnosed with atypical Turner syndrome
due to structural X chromosome abnormalities, in order to illustrate
some rare variants and to discuss particularities and cytogenetic
diversity of Turner syndrome .