Autoimmune lymphoproliferative syndrome due to FAS mutations outside the signal-transducing death domain: molecular mechanisms and clinical penetrance.
Genet Med
; 14(1): 81-9, 2012 Jan.
Article
en En
| MEDLINE
| ID: mdl-22237435
ABSTRACT
PURPOSE:
Autoimmune lymphoproliferative syndrome is a disorder of lymphocyte apoptosis. Although FAS molecules bearing mutations in the signal-transducing intracellular death domain exhibit dominant-negative interference with FAS-mediated apoptosis, mechanisms for pathology of non-death domain FAS mutations causing autoimmune lymphoproliferative syndrome are poorly defined.METHODS:
RNA stability, protein expression, ligand binding, and ability to transmit apoptosis signals by anti-FAS antibody or FAS ligand were determined for a cohort of 39 patients with non-death domain autoimmune lymphoproliferative syndrome. Correlations between mutation type and disease penetrance were established in mutation-positive family members.RESULTS:
Frameshifts or transcriptional stop mutations before exon 7 resulted in messenger RNA haploinsufficiency, whereas an amino-terminal signal sequence mutation and certain intracellular truncations prevented cell surface localization of FAS. All resulted in decreased FAS localization, inability to bind FAS ligand, and reduced FAS ligand-induced apoptosis. Extracellular missense mutations and in-frame deletions expressed defective FAS protein, failed to bind FAS ligand, and exhibited dominant-negative interference with FAS-mediated apoptosis. Mutation-positive relatives with haploinsufficient or extracellular mutations had lower penetrance of autoimmune lymphoproliferative syndrome clinical phenotypes than did relatives with death domain mutations.CONCLUSION:
We have defined molecular mechanisms by which non-death domain FAS mutations result in reduced lymphocyte apoptosis, established a hierarchy of genotype-phenotype correlation among mutation-positive relatives of patients with autoimmune lymphoproliferative syndrome, and demonstrated that FAS haploinsufficiency can lead to autoimmune lymphoproliferative syndrome.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptor fas
/
Penetrancia
/
Síndrome Linfoproliferativo Autoinmune
/
Mutación
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Genet Med
Asunto de la revista:
GENETICA MEDICA
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos