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in this lecture we will discuss
Klinefelter syndrome and Turner syndrome
these are genetic problems with the sex
chromosomes so let's start with
Klinefelter syndrome these patients
usually have male hypogonadism they have
two or more X chromosomes and one or
more Y chromosomes most commonly two x's
and one Y like you can see in this
patient's karyotype this occurs in 1 out
of 650 live births so it's not that
uncommon this is generally due to
maternal or paternal nondisjunction
during meiosis as they're making either
the sperm or the egg
this is there's a slightly increased
risk of this happening in mothers who
have are of advanced maternal age
sometimes Klinefelter syndrome patients
are fertile and can go on to have their
own children fertile Klinefelter
syndrome patients have a low recurrence
of Klinefelter syndrome in their
offspring but the offspring do carry a
very small increased risk of chromosomal
abnormalities so let's review the
clinical features of Klinefelter
syndrome they often suffer infertility
they may have hypogonadism with small
testes they often have gynecomastia in
adolescence as a result of an imbalance
between testosterone and estrogens
you'll notice they have reduced body
hair they will be tall and have a
pear-shaped stature to them and they
occasionally have educational and
psychological problems so how do we
diagnose Klinefelter syndrome if we
suspect a patient might have it
well first we will send a karyotype or
an array comparative genomic
hybridization this will make our
definitive diagnosis we will also screen
these patients when they are adult males
for infertility that's useful then for
them to know about for often they have a
decreased sperm count it's important to
check that testosterone levels they will
often have a decreased testosterone in
the face of hyper
no trap tropism in other words they have
hyper gonadotropic hypogonadism their
testes are non-responsive to LH and FSH
so they have high LH and FSH hormone
levels so how do we improve these
patients lives the first thing that's
very important is they should receive
testosterone therapy this will help a
number of things especially their facial
and body hair issues it will improve
their strength and muscle size it will
improve their energy level it will help
them with libido issues it will help
them with confidence and it will help
them with concentration so we often will
refer these patients to reproductive
specialists or infertility specialists
as well to help them with various
reproductive options if they should
decide to have a child
so let's focus now on Turner syndrome
Turner syndrome is a pulse partial or
complete monotony of the X chromosome
this results in hypogonadism in the
phenotypic female the instance is about
one in two thousand live births so how
does this happen well more than 60
percent are due to a de novo mitotic
nondisjunction in the paternal sex
chromosomes so the dad has an X and a Y
and instead of splitting into one X and
one Y sperm there's basically an X Y
sperm and an empty sperm and the empty
sperm now then goes and fertilizes the
egg creating a single X chromosome
Turner sinem occurs essentially only in
females males can be mosaic for Turner
syndrome this is rare but it can happen
where a male has some cells that are 45
X and other cells that are 46 X Y so
what are the symptoms and females of
Turner syndrome these are important to
remember these patients will have a
delayed puberty they will often have
amenorrhea this is from go nate'll
dysfunction they may have premature
ovarian failure
this results in infertility and some
patients may have some learning
disabilities especially in math but
generally these patients are cognitively
normal patients with Turner syndrome may
have short stature in fact they almost
always do they have low set ears a low
hairline and you may notice a webbed
neck or a broadened neck root
additionally you can see small jaw a
shield chest which is a broadened or
widened chest often with widened space
nipples you may see cubed Asahi's or
outward turned elbows they may have a
horseshoe kidney internally which they
may not even know about and they can
develop congenital heart disease so how
do we test and when do we test for
Turner syndrome
you should consider attempting prenatal
diagnosis if the fetal ultrasound shows
intrauterine growth restriction fetal
edema a coarctation of the aorta or
cystic hygroma in this case if a parent
wishes to do prenatal testing we
generally do chorionic villus sampling
or amniocentesis with karyotype
postnatally the diagnosis is made by
karyotype or AC GH just like in
Klinefelter syndrome so what therapy do
we provide these patients after initial
leave died making the diagnosis we will
screen them generally with an
echocardiogram or a renal ultrasound
especially paying attention to any
abnormalities of the heart such as a or
tech problems or if there's an abnormal
kidney additionally we will typically
check them for their thyroid function
we'll do an eye exam and we'll assess
for scoliosis which is a little bit more
common in these patients it's important
to refer these patients to a pediatric
endocrinologist for hormonal replacement
these patients will receive estrogen
progestin and growth hormone if you look
at this picture here are two patients
with Turner syndrome the one on the Left
received no growth hormone and the one
on the right received growth hormone
growth hormone is indicated in this
patients and can really help them in
terms of achieving an important stature
the reason why we give it is because for
patients who don't achieve 5 feet of
height this can result in significant
impairments and their ability to
function in the world it may be simply
hard for them to drive a car we want
these patients to live the most
fulfilled lives they can it's also
important to refer these patients to
fertility specialists for consideration
of their reproductive options when they
enter into adulthood so that's my review
of Turner syndrome and Klinefelter
syndrome thanks for your time
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