title: Fatal immune dysregulation due to a gain of glycosylation mutation in lymphocyte perforin.
abstract: Mutations in the perforin gene (PRF1) are a common cause of the fatal immune dysregulation disorder, familial hemophagocytic lymphohistiocytosis (type 2 FHL, FHL2). Here we report a female infant born with biallelic PRF1 mutations: a novel substitution, D49N, and a previously identified in-frame deletion, K285del. We assessed the effects of each mutation on the cytotoxicity of human NK cells in which the expression of endogenous perforin was ablated with miR30-based short hairpin (sh) RNAs. Both mutations were detrimental for function, thereby explaining the clinically severe presentation and rapidly fatal outcome. We demonstrate that D49N exerts its deleterious effect by generating an additional (third) N-linked glycosylation site, resulting in protein misfolding and degradation in the killer cell. Our data provide a rationale for treating some cases of type 2 familial hemophagocytic lymphohistiocytosis, based on the pharmacologic inhibition or modification of glycosylation.
authors.affiliation: Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors.forename: Jenny
authors.initials: J
authors.lastname: Chia
authors.forename: Kevin
authors.initials: K
authors.lastname: Thia
authors.forename: Amelia J
authors.initials: AJ
authors.lastname: Brennan
authors.forename: Margaret
authors.initials: M
authors.lastname: Little
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Williams
authors.forename: Jamie A
authors.initials: JA
authors.lastname: Lopez
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Trapani
authors.forename: Ilia
authors.initials: I
authors.lastname: Voskoboinik
mesh_terms: D001483:Base Sequence; D002478:Cells, Cultured; D004252:DNA Mutational Analysis; D017809:Fatal Outcome; D005260:Female; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D007154:Immune System Diseases / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D007231:Infant, Newborn; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D009102:Multiple Organ Failure / Q000235:genetics / Q000276:immunology; D020125:Mutation, Missense / Q000502:physiology*; D010375:Pedigree; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology
chemical_list: C510468:PRF1 protein, human; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin