Zellweger syndrome is a rare congenital disorder characterized by the reduction or absence of functional peroxisomes in the cells of an individual. It is one of a family of disorders called Zellweger spectrum disorders which are leukodystrophies. Zellweger syndrome is named after Hans Zellweger (1909–1990), a Swiss-American pediatrician, a professor of pediatrics and genetics at the University of Iowa who researched this disorder.
Glycerophospholipids of biochemical relevance are divided into three subclasses based on the substitution present at the sn-1 position of the glycerol backbone: acyl, alkyl and alkenyl. Of these, the alkyl and alkenyl moiety in each case form an ether bond, which makes for two types of ether phospholipids, plasmanyl, and plasmenyl. Plasmalogens are plasmenyls with an ester linked lipid at the sn-2 position of the glycerol backbone, chemically designated 1-0(1Z-alkenyl)-2-acyl-glycerophospholipids. The lipid attached to the vinyl ether at sn-1 can be C16:0, C18:0, or C18:1, and the lipid attached to the acyl group at sn-2 can be C22:6 ω-3 or C20:4 ω-6, . Plasmalogens are classified according to their head group, mainly as PC plasmalogens (plasmenylcholines) and PE plasmalogens (plasmenylethalomines) Plasmalogens should not be confused with plasmanyls.
Refsum disease is an autosomal recessive neurological disease that results in the over-accumulation of phytanic acid in cells and tissues. It is one of several disorders named after Norwegian neurologist Sigvald Bernhard Refsum (1907–1991). Refsum disease typically is adolescent onset and is diagnosed by above average levels of phytanic acid. Humans obtain the necessary phytanic acid primarily through diet. It is still unclear what function phytanic acid plays physiologically in humans, but has been found to regulate fatty acid metabolism in the liver of mice.
Cutis laxa or pachydermatocele is a group of rare connective tissue disorders in which the skin becomes inelastic and hangs loosely in folds.
Peroxisomal disorders represent a class of medical conditions caused by defects in peroxisome functions. This may be due to defects in single enzymes important for peroxisome function or in peroxins, proteins encoded by PEX genes that are critical for normal peroxisome assembly and biogenesis.
Peroxin-7 is a receptor associated with Refsum's disease and rhizomelic chondrodysplasia punctata type 1.
Infantile Refsum disease (IRD) is a rare autosomal recessive congenital peroxisomal biogenesis disorder within the Zellweger spectrum. These are disorders of the peroxisomes that are clinically similar to Zellweger syndrome and associated with mutations in the PEX family of genes. IRD is associated with deficient phytanic acid catabolism, as is adult Refsum disease, but they are different disorders that should not be confused.
Peroxisomal targeting signal 1 receptor (PTS1R) is a protein that in humans is encoded by the PEX5 gene.
Peroxisome biogenesis factor 1, also known as PEX1, is a protein which in humans is encoded by the PEX1 gene.
Peroxisomal membrane protein PEX14 is a protein that in humans is encoded by the PEX14 gene.
Peroxisomal biogenesis factor 2 is a protein that in humans is encoded by the PEX2 gene.
Peroxisomal membrane protein PEX13 is a protein that in humans is encoded by the PEX13 gene. It located on chromosome 2 next to KIAA1841
Peroxisomal biogenesis factor 3 is a protein that in humans is encoded by the PEX3 gene.
Peroxisome assembly factor 2 is a protein that in humans is encoded by the PEX6 gene. PEX6 is an AAA ATPase that localizes to the peroxisome. PEX6 forms a hexamer with PEX1 and is recruited to the membrane by PEX26.
Peroxisome biogenesis factor 10 is a protein that in humans is encoded by the PEX10 gene. Alternative splicing results in two transcript variants encoding different isoforms.
Peroxisomal membrane protein PEX16 is a protein that in humans is encoded by the PEX16 gene.
X-linked recessive chondrodysplasia punctata is a type of chondrodysplasia punctata that can involve the skin, hair, and cause short stature with skeletal abnormalities, cataracts, and deafness.
Heimler syndrome is a rare autosomal recessive condition characterized by sensorineural hearing loss, amelogenesis imperfecta, nail abnormalities and occasional or late-onset retinal pigmentation
Cousin syndrome is a genetic condition characterized by short stature at birth, a short neck with low-positioned external ears, as well as congenital malformations of the skeletal system affecting the shoulders, the pelvis, the neck, and the limbs. The condition determines physical disability, particularly affecting deambulation, and hearing loss while intelligence is not affected.
