European Human Genetics Conference 2007 June 16 – 19, 2007 ...
European Human Genetics Conference 2007 June 16 – 19, 2007 ...
European Human Genetics Conference 2007 June 16 – 19, 2007 ...
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Clinical genetics<br />
Posters<br />
Po01. Clinical genetics<br />
P0001. A 17q21.31 microduplication (including MAPT) and a<br />
2q22.3q23.1 microdeletion (including ACVR2A) detected by<br />
routine array-CGH analysis using 244k Agilent oligoarrays in two<br />
patients with mental retardation and dysmorphic features<br />
M. Kirchhoff1 , A. M. Bisgaard1 , M. Duno1 , F. J. Hansen2 , H. Rose1 , M.<br />
Schwartz1 ;<br />
1 2 Department of Clinical <strong>Genetics</strong>, Rigshospital, Copenhagen, Denmark, Department<br />
of Pediatric Neurology, Rigshospital, Copenhagen, Denmark.<br />
Two cases with de novo chromosomal imbalances detected by routine<br />
screening using 244k Agilent oligoarrays are presented. In case<br />
1, a microduplication of 17q21.31 was found (approximately 0.5 Mb).<br />
The duplication is reciprocal to the recently described 17q21.31 microdeletion<br />
and includes the MAPT gene. The patient is a nine-year-old<br />
girl with severe psychomotor developmental delay. Her facial dysmorphism<br />
includes a low anterior and posterior hairline, a small nose with<br />
a flat root, a long philtrum, and small widely spaced teeth. In addition,<br />
she has microcephaly, abnormal fingers and toes, and hirsutism with<br />
very long hairs on her back. In case 2, a microdeletion of 2q22.3q23.1<br />
was found (approximately 0.4 Mb). The deletion includes the ACVR2A<br />
gene, which has been associated with cranio-facial development in<br />
mice. The patient is a three-year-old girl. Her psychomotor development<br />
is approximately 12 months delayed. Her facial dysmorphism<br />
includes lateral extension of eyebrows, a low anterior hairline, long<br />
palpebral fissures, a high nasal bridge giving the impression of deepset<br />
eyes, a bulbous nasal tip, a thin upper lip, and micrognathia/retrognathia.<br />
In addition, she is microcephalic, hypermobile and hypotonic.<br />
Beside the two patients an outline will be presented from seven months<br />
of routine CGH-analysis using 244k Agilent oligoarrays of patients with<br />
mental retardation and dysmorphic features.<br />
P0002. Clinical and cytogenetic aspects in two children with<br />
trisomy 18<br />
M. Budisteanu 1 , A. Arghir 1 , I. Minciu 2 , S. Magureanu 2 , G. Chelu 1 , A. Lungeanu 1 ;<br />
1 ”Victor Babes” National Institute of Research and Development, Bucharest,<br />
Romania, 2 Clinical Hospital of Psychiatry “Prof. Dr. Al. Obregia”, Bucharest,<br />
Romania.<br />
Objective: The authors present two cases of trisomy 18 with different<br />
clinical and cytogenetic characteristics.<br />
Material and methods: The children were admitted to the Department<br />
of Pediatric Neurology of the Clinical Hospital Al. Obregia, Bucharest<br />
for evaluation of a delayed psychomotor development. They were included<br />
in a large study, part of a national research program, which<br />
investigate the cytogenetic causes of MR in children. First case, an<br />
eight years old girl, showed: dysmorphic features, severe MR, hyperkinesia<br />
with self-injurious behavior. Second case, a four months old<br />
girl, displayed the clinical phenotype characteristic of Edwards syndrome<br />
(including dysmorphic features, failure to thrive, arthrogryposis,<br />
epileptic seizures, brain malformation). The children were investigated<br />
cytogenetically by karyotype with GTG-banding.<br />
Results: In the first case, the cytogenetic investigation revealed a partial<br />
trisomy 18pter-18q21. In the second case, the diploid karyotype<br />
showed a duplication of the long arm of chromosome 18.<br />
Conclusions: The phenotype of the patients with trisomy 18 can be different<br />
depending on the specific triplicated chromosomal region. For<br />
a better description of the sequences involved in the breakpoints in<br />
this two cases, we intend to extend the study by applying molecular<br />
genetic methods.<br />
P0003. CYP21A2 genotyping in an Italian population with 21hydroxylase<br />
deficiency: molecular characterization of 1050<br />
alleles<br />
L. Baldazzi1 , S. Menabò1 , A. Balsamo1 , M. Barbaro1,2 , A. Nicoletti1 , G. Cangemi1<br />
, A. Cicognani1 ;<br />
1Pediatric Department S.Orsola-Malpighi University Hospital, Bologna, Italy,<br />
2Center for Molecular Medicine Karolinska University Hospital, Stockolm, Sweden.<br />
Steroid 21-hydroxylase deficiency (21OHD), an autosomal recessive<br />
disorder caused by mutations in the CYP21A2 gene and responsible for<br />
>90% of cases of congenital adrenal hyperplasia, presents a wide phe-<br />
notypic spectrum ranging from a severe classical form (CL, 1/15000)<br />
with or without salt wasting, through to a mild nonclassical form (NC,<br />
1/100), to a hyperandrogenic adult form. The active gene and the inactive<br />
pseudogene CYP21P are organized in a complex locus on chromosome<br />
6p21.3. Most of the genetic lesions that cause 21OHD are<br />
deletions/conversions (often giving rise to chimeric CYP21P/CYP21<br />
genes) or various gene conversion-type mutations resulting in CYP21<br />
genes carrying one/multiple pseudogenic mutations. Mutations arising<br />
independently of the pseudogene are rare.<br />
A molecular strategy analysis that combines specific PCR (designated<br />
to avoid allele dropout phenomena caused by pseudogene sequences<br />
and to discover a chimeric gene), sequencing of the entire CYP21A2<br />
gene region (from nt-420 to nt+2907), as well as intragenic polymorphism<br />
segregation analysis, enabled us to characterize a total of 1050<br />
alleles of: 383 21OHD patients (<strong>16</strong>2 CL, 231 NC) and 136 hyperandrogenic<br />
subjects with 98.8% of mutation detection. Mutations were<br />
confirmed in the parents in 85% of the cases. Single/multiple pseudogene-derived<br />
mutations account for 93.2% of the alleles, whereas<br />
5.6% carry a rare/new mutation, mostly missense mutations affecting<br />
a conserved residue. Functional studies of 3 new mutations confirmed<br />
their implication in the phenotype observed. The genotype/phenotype<br />
relationship was generally good. Further studies will focus on rare variants<br />
in the non coding regions associated with mild forms.<br />
P0004. A boy with 3q29 microdeletion and congenital mitral<br />
valve stenosis<br />
A. Stray-Pedersen1 , K. L. Eiklid2 , K. Ramstad1 , O. K. Rødningen2 ;<br />
1 2 Rikshospitalet-Radiumhospitalet, Oslo, Norway, Ulleval University Hospital,<br />
Oslo, Norway.<br />
We present an 8 year old boy with congenital mitral valve stenosis<br />
and mental retardation. Clinical findings: progressive microcephaly,<br />
epicanthus, antimongoloid eye shape, oedematous eyelids, prominent<br />
nasal tip, irregularly and widely spaced teeth. He has hypotonic musculature<br />
with pronounced joint laxity both elbows. He has overriding 2nd toes, fetal pads toes and fingers. He is developmentally retarded. He<br />
started to walk at 23 months of age. His language is severely delayed,<br />
and he has autistic-like features.<br />
Array CGH using CytoChip (BlueGnome Ltd.) revealed an interstitial<br />
microdeletion of chromosome 3q29. This microdeletion is reported<br />
in only 7 patients worldwide. The clinical phenotype in the reported<br />
cases is variable despite an almost identical deletion size. It includes<br />
mild/moderate mental retardation and progressive microcephaly with<br />
mildly dysmorphic facial features (long and narrow face, short philtrum<br />
and high nasal bridge).<br />
The phenotype in our patient is very similar to the other cases, but<br />
mitral valve stenosis is not reported in the 7 other patients. However,<br />
early death (at 3mo-5y) caused by cardiac events has been reported<br />
in some of the other patients with 3q29 microdeletion, and terminal<br />
deletions of chromosome 3q are associated with congenital heart defect.<br />
The microdeletion encompasses several genes including PAK2.<br />
This gene is the autosomal homologue of a known X-linked mental<br />
retardation gene (PAK3), and might be the cause of mental retardation<br />
in the patients. The specific gene causing the heart defect reported in<br />
our patient is unknown. Our patient’s phenotype broadens the clinical<br />
spectrum of the 3q29 microdeletion syndrome.<br />
P0005. Subtelomeric 6p deletion: clinical and array-CGH findings<br />
in two patients<br />
I. Filges1 , D. Martinet2 , F. Bena1 , N. Besuchet2 , I. Bouchardy1 , A. C. Gaide2 , S.<br />
E. Antonarakis1 , J. Beckmann2 , M. A. Morris1 , A. Bottani1 , M. C. Addor2 ;<br />
1Medical <strong>Genetics</strong> Service, Geneva University Hospitals, Geneva, Switzerland,<br />
2Medical <strong>Genetics</strong> Service, Centre Hospitalier Universitaire Vaudois, Lausanne,<br />
Switzerland.<br />
Approximately 30 patients with subtelomeric 6p deletion have been<br />
reported. A recognizable phenotype, including hypertelorism, downslanting<br />
palpebral fissures, flat nasal bridge and dysplastic ears, has<br />
been delineated. In addition to variable mental retardation and potential<br />
hearing deficit, there is a distinctive malformation pattern, which<br />
comprises anterior eye chamber malformations, posterior fossa/cerebellar<br />
anomalies, and heart defects.<br />
Patient 1 is an 8-month-old female born with normal growth parameters,<br />
typical facial features of 6pter deletion, bilateral corectopia, and<br />
protruding tongue. She has severe developmental delay, profound bi-