Essay/Term paper: Turner syndrome

Essay, term paper, research paper:  College Papers

There are many possible reasons why a child may grow slowly, including:
hereditary factors (short parents), diseases affecting the kidneys;
heart, lungs or intestines; hormone imbalances; severe stress or
emotional deprivation; infections in the womb before birth; bone
diseases; and genetic or chromosomal abnormalities.
The Turner Syndrome (known as Ullrich-Turner Syndrome in Germany) is a
congenital disease. A German doctor named Ullrich published his article
in 1930. American doctor Henry Turner recognized a pattern of short
stature and incomplete sexual maturation in otherwise normal females. He
published a comprehensive medical description of the syndrome. It was
not until 1959, that it became clear the syndrome was due to lack of sex
chromosome material. Turner's Syndrome is a rare chromosomal disorder
that affects one in approximately 2,500 females. Females normally have
two X-chromosomes. However, in those with Turner's Syndrome, one X
chromosome is absent or is damaged.
OTHER NAMES
Depending on the doctor, Turner's Syndrome may be diagnosed with one of
the following alternative names: 45 - X Syndrome, Bonnevie-Ulrich
Syndrome, Chromosome X, Monosomy X, Morgagni-Turner-Albright Syndrome,
Ovarian Dwarfism, Turner Type, among others.
SYNDROME CHARACTERISTICS
A reduced growth in height is the commonest visible characteristic of
the syndrome, (the average adult height is 4 feet 8 inches) and may be
the only sign before puberty. Their body proportions are normal. Girls
with this syndrome may have many middle ear infections during childhood;
if not treated, these chronic infections could cause hearing loss. Up to
the age of about 2 years, growth in height is approximately normal, but
then it lags behind that of other girls. Greatly reduced growth in
height of a female child should lead to a chromosome test if no
diagnosis has already been made. Early diagnosis is very importance in
order to be able to give enough correct information to the parents, and
gradually to the child herself, so that she has the best possibilities
for development. Early diagnosis is also important in case surgical
treatment of the congenital heart defect (seen in about 20 per cent of
cases) is indicated. The commonest defect is a narrowing of the main
artery from the heart aortic coarctation. A regular ultrasound
examination of the heart is recommended in all girls with Turner
syndrome. This type of heart defect is present at birth and can be
corrected surgically. If not present at birth, it does not develop later
in life. The lack of sexual development at puberty is the second most
common characteristic. Having abnormal chromosomes does not mean that
girls with Turner syndrome are not really female; they are women with a
condition that causes short stature and poorly developed ovaries.
Affected females may also exhibit the following symptoms: infertility,
kidney abnormalities, thyroid disease, heart disease, abnormalities of
the eyes and bones, webbed neck, low hairline, drooping of eyelids,
abnormal bone development, absent or retarded development of physical
features that normally appear at puberty, decrease of tears when crying,
simian crease (a single crease in the palm), a "caved-in" appearance to
the chest, puffy hands and feet, unusual shape and rotation of ears,
soft upturned nails, small lower jaw, arms turned out slightly at
elbows, shortened 4th fingers, small brown moles, hearing loss,
scoliosis, cataracts , scars, overweight, Chrohn disease.
Chromosome Patterns
The normal female has 46 chromosomes, of which the two sex chromosomes
are X-chromosomes. This is expressed as 46,XX (men: 46,XY). In many
women with Turner syndrome, one of the X-chromosomes lacks completely,
and the chromosome pattern then becomes 45,X.
The X-chromosome in women is the carrier of genes related to production
of ovaries and female sex hormones, and to growth in height. Girls with
Turner syndrome are generally born with ovaries and egg cells, but the
lack of X-chromosome material results in gradual disappearance of the
egg cells. At some point in childhood, usually during the first years of
life, no egg cells remain. Ovaries are then present without egg cells.
The female sex hormone (oestrogen), necessary for the girl to start
puberty, is usually produced by the egg cells. In girls with Turner
syndrome, insufficient oestrogen is produced for the girl to start
puberty. Neither spontaneous development of puberty nor the accompanying
growth spurts are seen in girls with Turner syndrome.
Cause
The cause of the change in the sex chromosome that leads to Turner
syndrome is not known, nor is it known why the different symptoms
related to the syndrome develop. Other chromosome defects are more often
seen in children of elderly mothers, sometimes also elderly fathers, but
this does not seem to apply to Turner syndrome. . In some cases of
Turner's Syndrome, however, one X chromosome is missing from the cells
(45,X); research studies suggest that approximately 40 percent of these
individuals may have some Y chromosomal material in addition to the one
X chromosome. In other affected females, both X-chromosomes may be
present, but one may have genetic defects. In still other cases, some
cells may have the normal pair of X-chromosomes while other cells do not
(45,X/46,XX mosaicism). Although the exact cause of Turner's Syndrome is
not known, it is believed that the disorder may result from an error
during the division (meiosis) of a parent's sex cells.
In about 80 per cent of cases, where the whole of one of the
X-chromosomes is missing (45,X), it is thought to be the father's
X-chromosome that is absent.
Treatment
In recent years, the condition has been treated using a growth hormone,
given as injections under the skin (subcutaneous) in the evening.
Experiments are relatively limited. So far, researchers think it will be
possible to increase the final height by 5-10 centimeters, depending on
the duration of treatment. Treatment is started at slightly different
ages in different countries, but often at an age of about 6-7 years.
In order to achieve puberty development and a body height of more than
the average of about 146 cm, oestrogen and growth hormone must be given.
Oestrogen therapy should start after one has taken the growth hormone
for at least two years (about 12-13 years old is average), using small
doses at first to promote sexual development. Oestrogen is gradually
supplemented by progesterone (a stronger female hormone) as the girl
matures. The treatment can be given as tablets, injections, or oestrogen
plaster.
Identification and Cure
Although Turner Syndrome can be identified in the fetus or with a blood
test, there is not a known cure for it.
With growth hormone replacement therapy and oestrogen injections (female
hormones), the female victim of Turner syndrome can live an outwardly
normal life. Ongoing research in reproduction and adoption make it
possible for these women to marry and raise children.