Gene Variant Identified in Families With Cold Urticaria

PLCG2 gene deletions associated with cold urticaria, immunodeficiency, and autoimmunity

THURSDAY, Jan. 12 (HealthDay News) -- The PLCG2 gene, which encodes phospholipase Cγ2, has been found to be associated with a dominantly inherited medical condition causing cold urticaria, immunodeficiency, and autoimmunity, according to a study published online Jan. 11 in the New England Journal of Medicine.

Michael J. Ombrello, M.D., of the National Human Genome Research Institute in Bethesda, Md., and colleagues characterized the genomics involved in a dominantly inherited complex of cold-induced urticaria, antibody deficiency, and susceptibility to infection and autoimmunity in three families of European descent.

The researchers found that cold urticaria was present in all affected subjects; variable manifestations included granulomatous rash, autoimmune thyroiditis, atopy, antinuclear antibodies, sinopulmonary infections, and other signs of immunodeficiency. The number of natural killer cells and class-switched memory B cells as well as serum IgM and IgA levels were reduced. Three distinct in-frame deletions involving the PLCG2 gene on chromosome 16q that codes for protein products with constitutive phospholipase activity were identified. When expressed in leukocytes, these deletions caused cellular signaling to be temperature-sensitive.

"In three families with a dominantly inherited syndrome of cold urticaria and pleiotropic immune dysregulation, we found that genomic deletions in PLCG2 were responsible for this unique phenotype," the authors write.

One author disclosed financial ties to Illumina Inc.

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