Norrin, also known as Norrie disease protein or X-linked exudative vitreoretinopathy 2 protein (EVR2) is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''NDP''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Mutations in the NDP gene are associated with the
Norrie disease
Norrie disease is a rare X-linked recessive genetic disorder that primarily affects the eyes and almost always leads to blindness. It is caused by mutations in the Norrin cystine knot growth factor gene, also referred to as Norrie Disease Pseudog ...
.
Function
Signaling induced by the protein Norrin regulates
vascular Vascular can refer to:
* blood vessels, the vascular system in animals
* vascular tissue
Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue ...
development of vertebrate retina and controls important blood vessels in the ear.
Norrin binds with high affinity to Frizzled 4, and Frizzled 4 knockout mice exhibit abnormal vascular development of the retina.
Clinical significance
NDP is the genetic locus identified as harboring mutations that result in
Norrie disease
Norrie disease is a rare X-linked recessive genetic disorder that primarily affects the eyes and almost always leads to blindness. It is caused by mutations in the Norrin cystine knot growth factor gene, also referred to as Norrie Disease Pseudog ...
. Norrie disease is a rare
genetic disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders ...
characterized by bilateral
congenital blindness that is caused by a vascularized mass behind each
lens
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...
due to a maldeveloped
retina
The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
(
pseudoglioma
Norrin, also known as Norrie disease protein or X-linked exudative vitreoretinopathy 2 protein (EVR2) is a protein that in humans is encoded by the ''NDP'' gene. Mutations in the NDP gene are associated with the Norrie disease.
Function
Signa ...
).
References
Further reading
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External links
GeneReviews/NIH/NCBI/UW entry on NDP-Related Retinopathies
Human proteins
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