turners syndrome

1. TURNER SYNDROME
Muni Venkatesh. P
Group 2

2. Turner syndrome
• Turner syndrome (TS): is a genetic condition that
only affects females.
• The condition is caused by an abnormal
chromosome and affects about one in every 2,500
baby girls, but is much more common among
pregnancies that do not survive to term
(miscarriages and stillbirths).
• TS was named after Dr Henry
Turner, who discovered the condition
in 1938.

3. How do people get Turner
syndrome???
• Turner syndrome is typically caused by
nondisjunction.
• a pair of sex chromosomes fails to separate
during the formation of an egg (or sperm), so,
when an abnormal egg unites with a normal
sperm to form an embryo, that embryo may end
up missing one of the sex chromosomes (X
rather than XX).
• Advanced maternal age is not
associated with an increased
incidence.

4. Cont…

5. Cont…
• The abnormality is not inherited from an
affected parent (not passed down from parent
to child).
• because women with Turner syndrome are
usually sterile and cannot have children.

6. Types of Turner syndrome
• Cases of TS where an X chromosome is
completely missing are sometimes referred to
as 'classical' Turner syndrome.
• About 30 percent of girls with the disorder are
only missing the X chromosome in some of their
cells. This mixed chromosome pattern is known
as mosaicism.
• Girls with this pattern may have
fewer symptoms because they still
have some normal (XX) cells.

7. Cont…
• Y chromosome material: In a small percentage
of cases of Turner syndrome, some cells have
one copy of the X chromosome and other cells
have one copy of the X chromosome and some Y
chromosome material.
• These individuals develop
biologically as girls, but the presence
of Y chromosome material increases
the risk of developing a type of
cancer called gonadoblastoma.

8. Genetics of turner’s syndrome
45,X 50%
46,X,i(Xq) 15%
45,X/46,XX mosaics 15%
45,X/46,X,i(Xq) mosaics about 5%
45,X, other X abnormality about 5%
Other 45,X/? mosaics about 5%

9. Characteristics
• Girls and women who have TS often have a wide
range of different medical symptoms, or
characteristics.
• However, there are two characteristics that
occur in almost all cases of TS. They are:
being shorter than average in
height
a lack of development of the
ovaries, leading to infertility

10. Cont…
• One of the missing genes on the X chromosome
is the SHOX gene, which is responsible for long
bone growth.
• The missing SHOX gene is the reason girls who
have the disorder are unusually short.
• Other missing genes regulate
ovarian development, which
influences sexual characteristics.

11. • Possible symptoms in young infants include:
 Swollen hands and feet
 Wide and webbed neck and a low or indistinct hairline
• A combination of the following symptoms may be seen
in older females:
 Absent or incomplete development at puberty
 A broad chest and widely spaced nipples
 Drooping eyelids , Dry eyes
 Infertility
No periods (absent menstruation)
Short height
Vaginal dryness
Arms that turn out slightly at the elbow

14. • Short stature (143-145cm tall)
• Loss of ovarian function
• Hormone imbalances( thyroid, diabetes)
• Stress and emotional deprivation
• Diseases affecting the kidneys, heart, lungs or
intestines
• Bone diseases
• Learning problems( esp. in maths)
Clinical features

15.  A heart murmur, sometimes associated with
narrowing of the aorta.
 A tendency to develop high blood pressure (so
this should be checked regularly).
 Scoliosis occurs in 10 percent of adolescent
girls
 The thyroid gland becomes under-active in
about 10 percent of women who have Turner
syndrome.
Older or over-weight women with
Turner syndrome are slightly more
at risk of developing diabetes.
Osteoporosis can develop because
of a lack of estrogen.

16. Diagnosis
• About half of the cases are diagnosed within
the first few months of a girl's life by the
characteristic physical symptoms .(swelling of
the hands and feet, or a heart defect).
• Other patients are diagnosed in
adolescence because they fail to
grow normally or go through
puberty.

17. Cont…
• When the doctor suspects Turner syndrome, a
blood sample can be used to make a karyotype
and the diagnosis can be confirmed.

18. Cont…
• Turner syndrome may be diagnosed during
pregnancy with a chorionic villus sampling (CVS)
or amniocentesis.
• Alternatively, an ultrasound can identify the
disorder by its physical symptoms before the
baby is born (signs of underdevelopment).

20. Treatment
• Hormone replacement therapy is the best way
to treat this disorder.
 Teenagers are treated with growth hormone to help
them reach a normal height.
They may also be given low doses of
androgens (male hormones which
females also produce in small quantities)
to increase height and encourage normal
hair and muscle growth.
 Some patients may take the female
hormone estrogen to promote normal
sexual development.