Christine Paulson
Biology 1010
June 7, 2013
Zellweger Syndrome
Zellweger Syndrome is a rare congenital disorder, characterized by the reduction or
absence of functional peroxisomes in the cells of an individual [1]. Peroxisomes are membranebound organelles found in all eukaryotic cells [2]. The major function of the peroxisome is the
breakdown of very long chain fatty acids through beta-oxidation. Peroxisomes contain enzymes
that oxidize certain molecules normally found in the cell. Notably very long chain fatty acids.
These oxidation reactions produce hydrogen peroxide which is toxic to the cell. So peroxisomes
also contain enzymes such as catalase that convert hydrogen peroxide into water and oxygen
thereby neutralizing the toxicity. They are involved in the catabolism of very long chain fatty
acids, D-amino acids and phospholipids. These are all critical for the normal function of brain,
liver and kidneys.
The occurrence of Zellweger Syndrome is characterized by a deficiency or absence of
functional peroxisomes, as well as a disruption of peroxisomal beta-oxidation. When this
malfunction occurs, there is an accumulation of branched and very long-chain fatty acids,
atypical bile acids, and leukotrienes. Typically, the biosynthesis of docosahexaenoic acid (DHA)
and plasmalogens are damaged, causing a radical reduction of these important lipid elements of
the central nervous system. The metabolism of pipecolic acid and the peroxisomal steps of
isoprenoid biosynthesis are also damaged to some extent. [3] Mutations in genes that encode the
enzymes and transporter proteins of the peroxisomes cause copper, iron and very long fatty acid
chains to accumulate in the blood and tissues such as the liver, brain and kidneys
There are a number of observable and clinical manifestations of Zellweger Syndrome that
include facial deformities, such as up slanting eyes, a high forehead and skin folds between the
upper and lower eyelids, as well as developmental and intellectual disabilities. Symptoms such
jaundice, high levels of iron, seizures, enlarged liver, inadequate sucking ability, poor muscle
tone, prenatal growth failure and gastrointestinal bleeds. [4] Some patients who suffer from
Zellweger Syndrome also experience impaired vision and hearing, liver failure and the inability
to move. Infections are treated by the use of antibiotics to guard against complications such as
pneumonia and respiratory distress. Most infants with this syndrome do not live beyond one
year of age. Infants with this syndrome are often born with facial deformity and intellectual
disabilities. There is no cure or standard treatment for Zellweger syndrome.
Christine Paulson
Biology 1010
June 7, 2013
Christine Paulson
Biology 1010
June 7, 2013
Annotated Bibliography
Baumgartner Matthias R., Saudubray Jean Marie. (2002) “Peroxisomal Disorders”
Seminars in Neonatology, 7:85-94. Retrieved from: http://www.biomedcentral.com/14712431/4/5
Weiss, Thomas C. (2013) “Zellweger Syndrome - Facts and Information”. Retrieved
from: http://www.disabled-world.com/disability/types/zellweger-syndrome.php