Rare Diseases Symptoms Automatic Extraction
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A random Abstract
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Diagnostic yield of various genetic approaches in patients with unexplained developmental delay or mental retardation.
[cohen syndrome]
The
underlying
cause
of
mental
retardation
remains
unknown
in
up
to
80
%
of
patients
.
As
chromosomal
aberrations
are
the
most
common
known
cause
of
mental
retardation
,
several
new
methods
based
on
FISH
,
PCR
,
and
array
techniques
have
been
developed
over
recent
years
to
increase
detection
rate
of
subtle
aneusomies
initially
of
the
gene
rich
subtelomeric
regions
,
but
nowadays
also
genome
wide
.
As
the
reported
detection
rates
vary
widely
between
different
reports
and
in
order
to
compare
the
diagnostic
yield
of
various
investigations
,
we
analyzed
the
diagnostic
yield
of
conventional
karyotyping
,
subtelomeric
screening
,
molecular
karyotyping
,
X-
inactivation
studies
,
and
dysmorphological
evaluation
with
targeted
laboratory
testing
in
unselected
patients
referred
for
developmental
delay
or
mental
retardation
to
our
cytogenetic
laboratory
(
n
=
600
)
and
to
our
genetic
clinic
(
n
=
570
)
.
In
the
cytogenetic
group
,
15
%
of
patients
showed
a
disease-related
aberration
,
while
various
targeted
analyses
after
dysmorphological
investigation
led
to
a
diagnosis
in
about
20
%
in
the
genetic
clinic
group
.
When
adding
the
patients
with
a
cytogenetic
aberration
to
the
patient
group
seen
in
genetic
clinic
,
an
etiological
diagnosis
was
established
in
about
40
%
of
the
combined
study
group
.
A
conventional
cytogenetic
diagnosis
was
present
in
16
%
of
combined
patients
and
a
microdeletion
syndrome
was
diagnosed
in
5
.
3
%
,
while
subtelomeric
screening
revealed
only
1
.
3
%
of
causes
.
Molecular
karyotyping
with
a
10
K
SNP
array
in
addition
revealed
5
%
of
underlying
causes
,
but
29
%
of
all
diagnoses
would
have
been
detectable
by
molecular
karyotyping
.
In
those
patients
without
a
clear
diagnosis
,
5
.
6
%
of
mothers
of
affected
boys
showed
significant
(
>
95
%
)
skewing
of
X-
inactivation
suggesting
X-
linked
mental
retardation
.
The
most
common
diagnoses
with
a
frequency
of
more
than
0
.
5
%
were
Down
syndrome
(
9
.
2
%
)
,
common
microdeletion
22
q
11
.
2
(
2
.
4
%
)
,
Williams-
Beuren
syndrome
(
1
.
3
%
)
,
Fragile-
X
syndrome
(
1
.
2
%
)
,
Cohen
syndrome
(
0
.
7
%
)
,
and
monosomy
1
p
36
.
3
(
0
.
6
%
)
.
From
our
data
,
we
suggest
the
following
diagnostic
procedure
in
patients
with
unexplained
developmental
delay
or
mental
retardation
:
(
1
)
Clinical
/
dysmorphological
investigation
with
respective
targeted
analyses
;
(
2
)
In
the
remaining
patients
without
an
etiological
diagnosis
,
we
suggest
conventional
karyotyping
,
X-
inactivation
screening
in
mothers
of
boys
,
and
molecular
karyotyping
,
if
available
.
If
molecular
karyotyping
is
not
available
,
subtelomeric
screening
should
be
performed
.
Diseases
Validation
Diseases presenting
"mental retardation"
symptom
achondroplasia
alexander disease
alpha-thalassemia
aniridia
aromatase deficiency
canavan disease
classical phenylketonuria
coats disease
cohen syndrome
cowden syndrome
cystinuria
dentin dysplasia
familial hypocalciuric hypercalcemia
homocystinuria without methylmalonic aciduria
hydrocephalus with stenosis of the aqueduct of sylvius
kabuki syndrome
kallmann syndrome
lamellar ichthyosis
lymphangioleiomyomatosis
monosomy 21
phenylketonuria
primary hyperoxaluria type 1
proteus syndrome
pyruvate dehydrogenase deficiency
sneddon syndrome
triple a syndrome
wolf-hirschhorn syndrome
zellweger syndrome
This symptom has already been validated