The GSN gene provides instructions for making two forms of a protein called gelsolin. One form remains inside the cell (cellular gelsolin) and the other form is released from the cell (secreted gelsolin). Both forms of the gelsolin protein attach (bind) to another protein called actin. Actin proteins are organized into filaments, which form a network (the cytoskeleton) that gives structure to cells and allows them to change shape and move. Gelsolin helps assemble or disassemble actin filaments. It is thought that, through this function, the gelsolin protein regulates the formation of the actin cytoskeleton.
Health Conditions Related to Genetic Changes
Lattice corneal dystrophy type II
At least two mutations in the GSN gene cause lattice corneal dystrophy type II. This condition is characterized by the accumulation of protein clumps called amyloid deposits in many tissues throughout the body, including the clear, outer covering of the eye (the cornea); the skin; and the nerves. These protein clumps contain the gelsolin protein.
GSN gene mutations that cause lattice corneal dystrophy type II change a single protein building block (amino acid) in the gelsolin protein: the amino acid aspartic acid at position 187. The most common mutation replaces the aspartic acid with the amino acid asparagine (written as Asp187Asn or D187N). Another mutation replaces the aspartic acid with the amino acid tyrosine (written as Asp187Tyr or D187Y).
The amino acid change is found in both the cellular and secreted forms of the gelsolin protein. However, only the secreted form of the protein is involved in the amyloid deposits. The altered gelsolin protein is broken down differently than the normal protein, which results in an abnormal gelsolin protein fragment that is released from the cell. These protein fragments accumulate and form amyloid deposits. Amyloid deposits in the eyes, skin, and nerves lead to the signs and symptoms of lattice corneal dystrophy type II, such as vision impairment; paralysis of facial muscles; and thick, sagging skin.More About This Health Condition
Other Names for This Gene
- actin-depolymerizing factor
- gelsolin isoform a precursor
- gelsolin isoform b
- gelsolin isoform c
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
- Janmey PA, Chaponnier C, Lind SE, Zaner KS, Stossel TP, Yin HL. Interactions of gelsolin and gelsolin-actin complexes with actin. Effects of calcium on actin nucleation, filament severing, and end blocking. Biochemistry. 1985 Jul 2;24(14):3714-23. Citation on PubMed
- Kangas H, Paunio T, Kalkkinen N, Jalanko A, Peltonen L. In vitro expression analysis shows that the secretory form of gelsolin is the sole source of amyloid in gelsolin-related amyloidosis. Hum Mol Genet. 1996 Sep;5(9):1237-43. Citation on PubMed
- Kwiatkowski DJ, Mehl R, Yin HL. Genomic organization and biosynthesis of secreted and cytoplasmic forms of gelsolin. J Cell Biol. 1988 Feb;106(2):375-84. Citation on PubMed or Free article on PubMed Central
- Levy E, Haltia M, Fernandez-Madrid I, Koivunen O, Ghiso J, Prelli F, Frangione B. Mutation in gelsolin gene in Finnish hereditary amyloidosis. J Exp Med. 1990 Dec 1;172(6):1865-7. Citation on PubMed or Free article on PubMed Central
- Maury CP, Liljeström M, Boysen G, Törnroth T, de la Chapelle A, Nurmiaho-Lassila EL. Danish type gelsolin related amyloidosis: 654G-T mutation is associated with a disease pathogenetically and clinically similar to that caused by the 654G-A mutation (familial amyloidosis of the Finnish type). J Clin Pathol. 2000 Feb;53(2):95-9. Citation on PubMed or Free article on PubMed Central
- Paunio T, Kangas H, Kalkkinen N, Haltia M, Palo J, Peltonen L. Toward understanding the pathogenic mechanisms in gelsolin-related amyloidosis: in vitro expression reveals an abnormal gelsolin fragment. Hum Mol Genet. 1994 Dec;3(12):2223-9. Citation on PubMed