Article

Clinical and molecular aspects of Turkish familial hemophagocytic lymphohistiocytosis patients with perforin mutations.

Hacettepe University, Faculty of Medicine, Department of Pediatrics, Division of Pediatric Hematology, 06100-Sihhiye, Ankara, Turkey.
Leukemia Research (Impact Factor: 2.76). 07/2008; 32(6):972-5. DOI: 10.1016/j.leukres.2007.11.033
Source: PubMed

ABSTRACT The aim of this study was to elucidate the pathologic sequence changes and associated clinical phenotypes in 9 new patients showing homozygosity for perforin gene among a total of 37 (24%) Turkish FHL families studied by linkage analysis. These 9 unrelated patients (5M/4F) were coming from consanguineous families and their presentation ages of systemic symptoms were ranged from birth to 15 years. Direct sequencing of coding exons of the perforin gene led to the identification of five different homozygous alterations. The nonsense W374X mutation was identified in three patients while four different missense mutations namely G149S, V50M, A91V and novel A523D were detected in the rest six patients.

0 Bookmarks
 · 
57 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Perforin plays a key role in the immune system via pore formation at the target cell membrane in the elimination of virus-infected and transformed cells. A vast number of observed mutations in perforin impair this mechanism resulting in a rare but fatal disease; familial hemophagocytic lymphohistiocytosis type 2, FHL2. Here we report a comprehensive in silico structural analysis of a collection of 76 missense perforin mutations based on a proposed pore model. In our model, perforin monomers oligomerize having cyclic symmetry in consistent with previously found experimental constraints yet having flexibility in the size of the pore and the number of monomers involved. Clusters of the mutations on the model map to three distinct functional regions of the perforin. Calculated stability (free energy) changes show that the mutations mainly destabilize the protein structure, interestingly however, A91V polymorphism, leads to a more stable one. Structural characteristics of mutations help explain the severe functional consequences on perforin deficient patients. Our study provides a structural approach to the mutation effects on the perforin oligomerization and impaired cytotoxic function in FHL2 patients.
    Protein Science 04/2013; · 2.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The involvement of the central nervous system (CNS) in familial hemophagocytic lymphohistiocytosis (FHL) has known to be limited to the brain, brain stem, and cerebellum. Herein, we report an 11-year-old boy who presented with neurological symptoms and was diagnosed as FHL by molecular diagnosis. The hemophagocytic lesions in the CNS were shown to extend to the thoracal level of spinal cord which completely disappeared after the completion of hemophagocytic lymphohistiocytosis-2004 protocol.
    Journal of Pediatric Neurosciences 09/2012; 7(3):194-6.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically heterogeneous disease. Presentation of the disease such as primarily fever, hepatosplenomegaly, and cytopenia, which are the results of functional degradation in cytotoxic T-lymphocytes and natural killer cells, activation of macrophages and T-lymphocytes, over production of proinflammatory cytokines, and hemophagocytosis. In all, 5 genetic loci have been identified in FHL, and all known affected genes encode critical components of the granule exocytosis pathway, which is essential for the release of cytotoxic granules and proteases that are necessary for targeted cell death. Herein we present an FHL patient with a severe clinical course and a very rare perforin gene mutation. The patient was homozygous for A665G mutation. However, the child died in a short period of time. Prenatal diagnosis was performed in the family and the fetus was found to be heterozygous for the mutation.
    Turkish Journal of Haematology 09/2012; 29(3):265-9. · 0.49 Impact Factor