3+ 4/2002 - Společnost pro pojivové tkáně

FETAL DNA IN MATERNAL PLASMA
Y. M. D. Lo, Shatin
Recently, fetal, DNA has been shown to
be present in maternal plasma and serum.
Using quantitative PCR techniques, fetal
DNA in maternal plasma and serum has
been demonstrated to be present in
amounts which are easily detectable. This
new source of fetal genetic material offers
a 8 powerful approach for the prenatal
diagnosis of many fetal genetic characteristics,
including blood group status and many
paternally-inherited genetic traits. Diseases
causing mutations which have been detected
in maternal plasma include myotonioc
dystrophy and achondroplasia. The finding
that part of the fetal DNA in maternal plasma
exists as intact fetal cells also offers new
possibilities for the prenatal diagnosis of
many chromosomal aneuploidies, including
trisomy 21.
Quantitative abnormalities of fetal, DNA
in maternal plasma and serum have also
been found in many disorders, including
preeclampsia, preterm labour and fetal
chromosomal aneuploidies. These result
suggest that fetal DNA measurement may
become a useful tool for the detection or
monitoring of these disorders. Apart from
its diagnostic implications, circulating fetal
DNA also opens up many previously unexplored
research opportunities for understanding
the fetomaternal relationship on
a molecular level.
THE LIMB GIRDLE MUSCULAR
DIVERSITY OF PATHOGENESIS
K. M. D. Bushby, Newcastle upon Tyne
The limb girdle muscular dystrophies
(LGMD) are a heterogenous group of disorders
which comprise both autosomal dom-
inant and recessive diseases. A gene and
protein based classification for these conditions
is now possible, based on their
underlying molecular pathology. Amongst
the autosomal dominant forms of LGMD,
mutations in genes encoding myotilin
(a component of the muscle sarcomere)
caveolin 3 (a component of caveolae in the
muscle fibre membrane) and lamin A/C,
nuclear envelope protein have been
described, while mutations in the colagen
VI genes account for a phenotypically overlapping
condition, Bethlem myopaty.
Amongst the autosomal recessive types of
LGMD are more diverse mutations in calpain
3, a protease predominantly expressed
in skeletal muscle cause a relatively common
type of LGMD, while mutations in dysferlin,
a membrane protein which contains
multiple C2 domains cause a form of muscular
dystrophy, which may present either
with predominantly proximal or distal disease.The
latest gene identified as cusing an
autosomal recessive LGMD, telethonin, is
a component of muscle sarcomere.
With these diverse disease mechanisms,
it is likely that a number of disease pathways
can contribute to the causation of these diseases.
In the meantime,impromevents in the
classification of this group have resulted in
clear benefits to a patients in terms of diagnosis
and the provision of prognostic and
genetic counselling information.
YEAST GENETICS AND HUMAN
BIOLOGY
P. Hieter,Vancouver
Yeast is arguably the most powerfull
experimental organism for learning about
the basic function of genes involved in
intracellular eukaryotic processes. The
combination of classical genetics, recombi-
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