Download Lecture 05. Organization of medical genetic counseling

Furdela Victoria
MD. Assistant
Pediatrics Department #2
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What is the genetic counseling?

Genetic counseling may be described as the process
through which individuals affected by, or at risk for
a problem which may be genetic or hereditary, are
informed of :
 The consequences of the disorder,
 The probability of suffering from or of
transmitting it to their offspring,
 The potential means of treating or of avoiding
the occurrence of the malformation or disease
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Establishing the correct diagnosis
Establishing the heredity family type
Calculation of the risk for next children with
heredity diseases
Explanation to parents about risk of heredity
diseases for next children and
maximum support in there decision

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It is important to draw the
pedigree or family. This
method helps to show the
number of involved family
members, their sexes and
ages of onset etc.
to determine the type of
inheritance and further
chances of recurrence of
the inherited disorder.
Healthy woman
Healthy man
Proband
Sex unknown
Dead
Abortion
Medical abortion
Still-birth
Marriage
Consanguineous marriage
Repeated marriage
Unmarriage
Siblings
Monozygotic twins
Dizygotic twins
No known pregnancy
Sterility
Known heterozygous
person
Carrier female
Pregnancy in progress
Affected person
Mongoloid eyes
Antimongoloid eyes

(1)Chromosomal disorders:
 Incidence: 1/200 live-born children, and 1/500
adults.
 Abnormalities :
 1) Numerical abnormalities : rarely inherited,
although the extra chromosome is transmit to the
offspring.
 2)Structural abnormalities, such as translocations,
May cause: little or no effect in carriers, but
predispose to reproductive problems such as
miscarriage and infertility.

CAUSE: Mutations in single genes, at
specific gene " loci.

Incidence: 1/300 individuals will
suffer from a monogenic disease
manifesting within the first two
decades .
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"Cytogenetics" is a word used to describe the
study of chromosomes.
The chromosomes need to be stained in order
to see them with a microscope.
When stained, the chromosomes look like
strings with light and dark "bands.
" A picture (an actual photograph from one
cell) of all 46 chromosomes, in their pairs, is
called a "karyotype."
Cytogenetic method
•This method give us possibility to
examine X and У sex chromatin
and autosomes to establish
karyotype.
Cytogenetic testing - Down syndrome
normal
abnormal
Cytogenetic testing - Deletions
Cytogenetic testing - Deletions
The term prenatal
diagnosis describes various
procedures (invasive and
non-invasive methods) of
prenatal diagnosis. The
procedures serve to detect
high-risk pregnancies,
high-risk childbirths and
disturbances of health at an
early stage and thus to
avert in time dangers for
life and health of mother
and child
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Clinical examination
Obstetric gynecologic examination
Microbiological examination
Non-invasive
methods
of
PND
are
such
prenatal
examinations that do not invade into the body of mother or
child. This includes various forms of sonography (acoustic
discharge measurement) and electrocardiography.
The side-effects of noninvasive methods for
mother and child are
assumed to be minimal.
Transcervical CVS is now usually performed at
10 to 12 completed gestational weeks. Absolute
contraindications to transcervical CVS include
active cervical or vaginal pathology (e.g.,
herpetic, chlamydial, or gonorrheal infection) or
maternal blood group sensitization. Relative
contraindications include leiomyoma
obstructing the cervical canal, bleeding from the
vagina within 2 weeks of planned CVS, and a
markedly retroverted, retroflexed uterus.46
Before CVS, fetal viability and normal fetal
growth must be confirmed by ultrasound. The
procedure is performed with a device that
consists of a plastic cannula enclosing a metal
obturator extending just beyond the catheter tip;
the diameter of most catheters is approximately
1.5 mm.
FETAL TISSUE SAMPLING