PRADER WILLI SYNDROME
WHAT IS PRADER WILLI SYNDROME?
Prader–Willi syndrome (PWS) is a rare
genetic disorder in which seven genes on
chromosome 15 are deleted or unexpressed
on the paternal chromosome.
It was first described in 1956 by Andrea
Prader, Heinrich Willi, Alexis Labhart,
Andrew Ziegler, and Guido Fanconi of
Symptoms are believed to
be caused by dysfunction
of a portion of the brain
called the hypothalamus.
The hypothalamus is a
small endocrine organ at
the base of the brain that
plays a crucial role in
many bodily functions like,
hunger and satiety,
temperature and pain
regulation, fluid balance,
puberty, emotions, and
dysfunction is believed to
lead to the symptoms of
PWS, it is unclear how the
genetic abnormality causes
There are two generally
recognized stages of the
In the first stage, infants with PWS
are hypotonic or "floppy", with very
low muscle tone.
Weak cry and a poor suck reflex are
typical. Babies with PWS usually are
unable to breastfeed and frequently
require tube feeding.
These infants may suffer from
"failure to thrive" if feeding
difficulties are not carefully
monitored and treated.
As these children grow older,
strength and muscle tone generally
Motor milestones are achieved, but
are usually delayed.
An unregulated appetite
characterizes the second stage of
This stage most commonly begins
between ages 2 and 6 years old.
Individuals with PWS lack normal
hunger and satiety cues.
They usually are not able to control
their food intake and will overeat if
not closely monitored.
Food seeking behaviors are very
In addition, the metabolic rate of
persons with PWS is lower than
Left untreated, the combination of
these problems will lead to morbid
obesity and its many complications.
OTHER CHARACTER ISTICS
o Prader-Willi syndrome is
considered a spectrum disorder,
meaning not all symptoms will
occur in everyone affected and
the symptoms may range from
mild to severe.
o People with Prader-Willi often
have some mental strengths as
well, such as skills in jigsaw
o If obesity is prevented, people
with the syndrome can live a
o Behavioral problems, usually
during transitions and
unanticipated changes, such as
stubbornness or temper tantrums
o Delayed motor skills and speech
due to low muscle tone
o Cognitive problems, ranging from
near normal intelligence to mild
mental retardation; learning
disabilities are common
o Repetitive thoughts and
o Collecting and hoarding of
o Picking at skin
o Low sex hormone levels
FISH (fluorescence in situ hybridization)
A cytogenetic technique used to detect and localize the presence or absence of
specific DNA sequences on chromosomes.
FISH uses fluorescent probes that bind to only those parts of the chromosome with
which they show a high degree of sequence similarity.
Fluorescence microscopy can be used to find out where the fluorescent probe
bound to the chromosomes.
FISH is often used for finding specific features in DNA for use in genetic
counseling, medicine, and species identification.
FISH can also be used to detect and localize specific mRNAs within tissue samples.
In this context, it can help define the spatial-temporal patterns of gene expression
within cells and tissues.
Methylation of mammalian DNA has long been recognized to play a major role
in different cellular functions as development or control of gene expression and is
generally associated with transcriptional repression.
fast magnetic assay for specific isolation of CpG-methylated DNA
Ultra offers a fast magnetic assay capable of efficiently isolating methylated CpG
islands from fragmented genomic DNA*.
In multiple studies, human growth hormone (HGH) has been found to be beneficial
in treating Prader-Willi syndrome.
In June of 2000, HGH was officially recognized by the Federal Drug Administration
(FDA) in the United States and other countries for use in patients with Prader-Willi
HGH is effective not only in increasing height, but also
Decreasing body fat, increasing muscle mass
Improving weight distribution
Increasing bone mineral density
Despite this, many difficult symptoms associated with PWS remain untreated.
To date, no effective medications have been found to regulate appetite.
Inability to control food intake is often the biggest obstacle keeping those with
PWS from living independently.
In addition, medical treatment of the psychiatric and behavioral issues associated
with PWS has produced inconsistent results.
Exercise and physical activity can help control weight and help
with motor skills.
Speech therapy may be needed to help with oral skills.