2008 Barcelona - European Society of Human Genetics

Molecular and biochemical basis of disease
P05.018
screening for cADAsiL in central italian patients
L. Pianese 1 , A. Cappelli 1,2 , M. Scarcella 3 , G. Cacchiò 3 , P. Staffolani 1 , M.
Ragno 3 ;
1 Laboratorio Medicina Molecolare, ASUR ZT13, Ascoli Piceno, Italy, 2 School of
Advanced Studies: Environmental Sciences and Public Health, Camerino, Italy,
3 U. O. Neurologia, ASUR ZT13, Ascoli Piceno, Italy.
Cerebral autosomal dominant arteriopathy with subcortical infarcts and
leukoencephalopathy (CADASIL) is an inherited autosomal dominant
condition characterized by a variable combination of recurrent cerebral
ischemic episodes, cognitive deficits, migraine with aura and psychiatric
symptoms . It results from mutations distributed throughout the
34 EGFRs (epidermal growth factor-like repeats) of the Notch3 gene,
leading to the addition or the loss of a cysteine residue .
We performed genetic testing for Notch3 mutations in 45 probands
of different family with suspected CADASIL who had been referred to
our service in 2007 . DNA samples were analyzed for mutations in all
exons of EGFRs using an appropriate screening protocol considering
the mutations distribution in exons gene .
The sequence analysis of Notch3 gene revealed the presence of three
previously reported missense mutations: C144F in exon 4, G528C in
exon 10 and R1006C in exon 19 . In particular, the mutation C144F was
found in one family, whereas the mutations G528C and R1006C were
found in two and seven families respectively, with the same regional
origin . These results suggest a higher frequency of exon 10 and 19
mutations in central Italy and confirm that the genetic procedures could
be optimized by a geographical region-oriented genetic analysis .
We are extending genetic analysis to the remaining exons of Notch3
gene in patients with clinical and strumental features more suggestive
of CADASIL phenotype, negative for EGFRs mutations .
P05.019
KRIT1 gene mutations in Sardinian patients with cerebral
cavernous malformations
M. A. Melis1 , M. Addis1 , R. Congiu1 , C. Meloni1 , A. Loi2 , M. Melis3 , M. Loi3 , M.
Cau1 ;
1 2 University of Cagliari, Cagliari, Italy, Ospedale Regionale per le Microcitemie,
Cagliari, Italy, 3Azienda Ospedaliera Brotzu, Cagliari, Italy.
Cerebral Cavernous Malformations (CCM) are CNS vascular anomalies
associated with seizures, headaches and hemorrhagic strokes and
represents 10 to 20 percent of cerebral lesions . CCM is present in 0 .1
to 0 .5 of the population . This disorder most often occurs sporadically
but may also be familial . Familial cases are inherited as a dominant
trait with incomplete penetrance and are estimated to account for 10-
40 % of the patients. The identification of the genes involved in such
disorders allow to characterize carriers of the mutations without clear
symptoms. The first gene involved in CCM1 is KRIT 1. In addition to
KRIT1 two other genes have been described: MGC4607 (CCM2) and
PDCD10 (CCM3) . We selected 14 patients belonging to seven Sardinian
families on the basis of clinical symptoms and Magnetic Resonance
results . MLPA analysis of KRIT1, MGC4607 and PDCD10 gave
negative results . Sequencing analysis of KRIT1 gene was performed
in all the patients. We identified a 4bp deletion in exon 9 leading to a
premature stop codon in a patient with clear phenotype . The same mutation
has been found in three relatives showing very mild symptoms .
In 5 subjects belonging to four unrelated families a unique nonsense
mutation (C329X) has been found . Haplotype analysis in these four
families revealed a common origin of the mutation . These data suggest
a “founder effect”, already described in different populations .
P05.020
Functional analysis of cD96, a causative gene for a form of c
(Opitz trigonocephaly) syndrome
T. Kaname 1,2 , K. Yanagi 1 , Y. Chinen 1 , Y. Makita 3 , N. Okamoto 4 , K. Kurosawa 5 ,
H. Maehara 1 , Y. Fukushima 6 , A. Bohring 7 , J. M. Opitz 8 , K. Yoshiura 9,2 , N. Niikawa
10,2 , K. Naritomi 1,2 ;
1 University of the Ryukyus, Nishihara-cho, Japan, 2 SORST, JST, Kawaguchi,
Japan, 3 Asahikawa Medical College, Asahikawa, Japan, 4 Osaka Medical Center
and Research Institute for Maternal and Child Health, Izumi, Japan, 5 Kanagawa
Children’s Medical Center, Yokohama, Japan, 6 Shinshu University School of
Medicine, Matsumoto, Japan, 7 Westfälische Wilhelms-Universität, Münster,
Germany, 8 University of Utah School of Medicine, Salt Lake City, UT, United
States, 9 Nagasaki University Graduate School of Biomedical Sciences, Na-
gasaki, Japan, 10 Health Sciences University of Hokkaido, Tobetsu-cho, Japan.
The C syndrome is characterized by trigonocephaly associated with
unusual facies, psychomotor retardation, redundant skin, joint and
limb abnormalities, and visceral anomalies . In an individual with
the C syndrome harboring a balanced chromosomal translocation,
t(3;18)(q13.13;q12.1), we identified a gene (CD96), which encodes
a member of the immunoglobulin superfamily, was disrupted at the
3q13 .3 breakpoint . In mutation analysis of karyotypically normal patients
with the C or C-like syndromes, we identified a missense mutation
in exon 6 of the CD96 gene in one patient and found reduced expression
in two patients . In order to know the function of CD96, we established
normal CD96 or the mutated CD96 expressed cell lines and
investigated their characters especially on cell-adhesion activity and
cell-growth activity . Cells with the normal CD96 protein increased both
the cell-adhesion and growth activities compared with MOCK cells . On
the other hand, cells with the mutated CD96 protein lost the activities in
vitro. These findings may indicate that CD96 mutations cause a form of
the C syndrome by interfering with cell adhesion and growth .
P05.021
Evidence on microRNA-mediated regulation of CDK5R1 gene
expression
S. Moncini 1 , M. Venturin 1 , A. Salvi 2 , V. Lanzi 1 , C. Sabelli 2 , G. De Petro 2 , S.
Barlati 2 , P. Riva 1 ;
1 University of Milan, Milan, Italy, 2 University of Brescia, Brescia, Italy.
CDK5R1 encodes for p35, an activator of CDK5, which is involved
in neuronal migration and differentiation during central nervous system
development and has been candidated for mental retardation .
We recently reported that the large 3’ untranslated region (3’UTR) of
CDK5R1 contains regulatory elements affecting transcript stability .
Besides several AREs, many microRNAs (miRNAs) target sites have
been predicted by PicTar software . We evaluated the expression of
nine pre-miRNAs, among the 20 miRNAs predicted to bind CDK5R1,
in six cell lines, including two neuroblastoma derived lines . Among the
expressed miRNAs, we observed that miR-15a, miR-103 and miR-
107 presented a high number of target sites with a free energy