Whole Genome Sequencing Identifies Novel Compound Heterozygous Lysosomal Trafficking Regulator Gene Mutations Associated with Autosomal Recessive Chediak-Higashi Syndrome.

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disease characterized by varying degrees of oculocutaneous albinism, recurrent infections, and a mild bleeding tendency, with late neurologic dysfunction. This syndrome is molecularly characterized by pathognomonic mutations in the LYST (lysosomal trafficking regulator). Using whole genome sequencing (WGS) we attempted to identify novel mutations of CHS based on a family of CHS with atypical symptoms. The two patients demonstrated a phenotypic constellation including partial oculocutaneous albinism, frequency upper respiratory infection or a marginal intelligence, without bleeding tendency and severe immunodeficiency. WGS revealed two compound LYST mutations including a maternally inherited chr1:235969126G > A (rs80338652) and a novel paternally inherited chr1: 235915327A > AT, associated with autosomal recessive CHS. These two variants fall in the coding regions of LYST, resulting in premature truncation of LYST due to R1104X/N2535KfsX2 induced incomplete translation. Notably, the heterozygous carriers (i.e. parents) were unaffected. Our finding also reveals decreased plasma serotonin levels in patients with CHS compared with unaffected individuals for the first time. The present study contributes to improved understanding of the causes of this disease and provides new ideas for possible treatments.

[MORPHOLOGICAL FEATURES OF NEUTROPHILS AND EOSINOPHILS GRANULES IN SAPPHIRE MINKS].

It has been established that sapphire minks have abnormality of subcellular structure of blood and bone marrow neutrophils and eosinophils. The abnormality consists in forming of abnormal "giant" granules. The si- ze and the number of abnormal granules significantly change during maturation of leucocytes in bone marrow. We have found differences between abnormal granules forming in neutrophils and eosinophils that depend on the maturing stage and the cells life cycle duration as well as morphofunctional features of these granulocytes.

Molecular determinants of platelet delta storage pool deficiencies: an update.

Delta storage pool deficiency (δ-SPD) is a rare heterogeneous group of platelet disorders characterized by a reduction in the number or content of dense granules. δ-SPD causes a mild to moderate bleeding diathesis characterized mainly by mucocutaneous bleeding. Currently, no specific treatment is available and the therapeutic approach is based on prevention of excessive bleeding. However, during the last few years, important insights into the pathophysiology of δ-SPD have been achieved using mouse models and dense granule deficiency-associated congenital diseases, such as Hermansky-Pudlak syndrome and Chediak-Higashi syndrome. It thus appears that δ-SPD represents a genetically heterogeneous group of intracellular vesicle biogenesis and/or trafficking disorders. This review summarizes recent data regarding the molecular mechanisms together with clinical features of the different types of δ-SPD. Although the molecular basis of isolated inherited δ-SPD remains currently unknown, next-generation sequencing strategies should enable researchers to identify the causative genes. Identification of those genes should contribute to our understanding of the pathophysiology, represent useful tools for genetic diagnosis, and eventually lead to new specific therapeutic approaches.

Chediak-Higashi syndrome presenting in accelerated phase.

Chediak-Higashi Syndrome (CHS) is a rare autosomal recessive disorder, characterized by silver hair, recurrent infections, partial oculo-cutaneous albinism, mild coagulation defect and progressive neuropathy. The characteristic feature of CHS is the presence of huge lysosomes and cytoplasmic inclusions within different body cells like the white blood cells. The disease has an early onset but usually presents in an accelerated phase. We present a case of a 2 years old boy with high grade fever, bilateral cervical lymphadenopathy, hepatosplenomegaly, abdominal distention of 28 days duration. He was diagnosed with Chediak-Higashi syndrome in accelerated phase on the basis of clinical presentation, morphological findings on peripheral blood film and bone marrow aspirate.

Unrelated cord blood transplantation can restore hematologic and immunologic functions in patients with Chediak-Higashi syndrome.

CHS is a rare hereditary fatal disease, if not treated. APs occur in 85% of patients and are usually the main cause of mortality, and HSCT from HLA-matched related and unrelated donors is the only effective treatment for CHS and prevents recurrences of APs. We reviewed the records of three patients with CHS who underwent UCBT at KHCC. Records were examined for clinical features at the time of UCBT, conditioning regimens, morbidities, and outcomes. Conditioning comprised BU, cyclophosphamide, horse ATG, and etoposide. All patients tolerated the conditioning well. Two patients are alive, one with mixed and the other with full donor chimerism; hematologic and immunologic defects of CHS have been corrected in both patients. They show no evidence of recurrences of APs and have normal growth and development. In patients with CHS who lack HLA-matched related and unrelated donors, UCBT is a suitable alternative source of stem cells to restore immunologic and hematologic functions and prevent AP relapses, even in mixed chimeric states. Long follow-up and close monitoring are essential to evaluate the long-term benefits of using UCBT in patients with CHS.

Electron opaque structures in human platelets: which are or are not dense bodies?

The dense bodies, also referred to as delta (delta) granules, present in human platelets are the storage sites for adenine nucleotides and serotonin. Stored products released following activation are important for platelet aggregation during hemostasis. Dense bodies are easily detected in thin sections of properly fixed platelets and in unfixed, unstained whole mount preparations. It is important to determine their presence and frequency with accuracy because they are absent or markedly reduced in platelet storage pool deficiency disorders. The present study has demonstrated that identification of dense bodies as not a simple matter. There are electron dense structures, including dense rings, glycosomes, "fuzzy" balls, chains, clusters and other dense elements, that may confuse the determination of true dense bodies. Even some alpha granules are sufficiently electron dense to be confused with delta granules when using densitometric techniques. The present work may prevent investigators from making diagnostic errors.

Familial and acquired hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition characterized by uncontrolled hyperinflammation on the basis of various inherited or acquired immune deficiencies. Cardinal symptoms are prolonged fever, hepatosplenomegaly and cytopenias. Central nervous system (CNS) symptoms are common. Biochemical markers include elevated triglyceride and ferritin, high levels of the alpha chain of the soluble interleukin-2 receptor and low fibrinogen. Impaired function of natural killer (NK) cells and cytotoxic T-cells (CTL) is a characteristic of all forms of HLH. Genetic HLH occurs in familial forms (FHLH), in which HLH is the primary and only manifestation, and in association with the immune deficiencies Chédiak-Higashi syndrome (CHS), Griscelli syndrome (GS) and X-linked lymphoproliferative syndrome (XLP), in which secondary HLH occurs sporadically. Most patients with acquired HLH have no known underlying immune deficiency. Both acquired and genetic forms are triggered by infections, mostly viruses, or other stimuli. HLH also occurs as a complication of rheumatic diseases (macrophage activation syndrome) and of malignancies. The recent discovery of several genetic defects causing FHLH as well as the identification of the genes responsible for CHS, GS and XLP have underscored the role of granule (perforin/granzymes)-mediated cytotoxicity in both the killing of infected cells and the termination of the immune response. The immediate aim of therapy is suppression of the increased inflammatory response by immunosuppressive/immunomodulatory agents and cytotoxic drugs. Genetic cases can only be cured with stem cell transplantation. Awareness of the clinical symptoms and of diagnostic criteria for HLH is crucial to starting life-saving therapy in time.

Chediak-Higashi syndrome: a case report.

A 5-month-old Chinese male infant was referred to the University Hospital, Kuala Lumpur for persistent fever, generalised rash and abdominal distension. Clinically he was suspected to have haemophagocytic lymphohistiocytosis. Haematological findings including the presence of several abnormal giant granules in neutrophils and single large azurophilic granules in many lymphocytes and monocytes in the peripheral blood established the diagnosis of Chediak-Higashi syndrome. The patient responded to allogeneic bone marrow transplant. This paper discusses the characteristic features, clinical course and management of this rare disorder. We suggest that peripheral blood film examination for the abnormal giant granules in granulocytes is an essential investigation in all young children with frequent recurrent infections or who are suspected to have virus-associated haemophagocytic syndrome or familial haemophagocytic lymphohistiocytosis.

Electron-dense chains and clusters in platelets from patients with storage pool-deficiency disorders.

Human platelets are known to contain inherently electron-opaque dense bodies, the storage sites for adenine nucleotides and serotonin, which can be identified under the electron microscope without fixation or staining. Recently we have reported that platelets also contain chains and clusters that are also opaque when examined by the whole-mount technique. The possibility that the newly described structures might be stages in the development of dense bodies requires consideration. The present study examined platelets from patients with Hermansky-Pudlak syndrome, Chediak-Higashi syndrome and platelet storage pool disease, whose cells are markedly deficient or lack dense bodies. Platelets from these individuals contained the same frequency of chains and clusters as found in platelets from normal controls. Thus, chains and clusters do not appear related to formation of dense bodies.

Alterations in erythrocyte membrane lipid and fatty acid composition in Chediak-Higashi syndrome.

Chediak-Higashi syndrome (CHS) is an autosomal recessive disease characterized by the presence of abnormally large cytoplasmic organelles in all body granule producing cells. The molecular mechanism for this disease is still unknown. Functional disorders in membrane-related processes have been reported. Erythrocyte membranes from four CHS patients and 15 relatives including obligatory heterozygous were studied to examine potential alterations in the lipid and fatty acid profile of erythrocyte membranes associated with this syndrome. Plasma concentrations of cholesterol, triglycerides, phospholipids, and apolipoproteins AI and B100, and the lipid components of very low-, intermediate-, low- and high-density lipoproteins were also determined. CHS erythrocyte membranes were found to be enriched with lipids in relation to protein and to show: (1) an increase in cholesterol and choline-containing phospholipids (sphingomyelin and phosphatidylcholine) that predominate in the outer monolayer, which is higher than the increase in phosphatidylserine and phosphatidylethanolamine, that are chiefly limited to the inner monolayer in normal red blood cells; (2) a relative palmitic acid and saturated fatty acid increase and arachidonic acid and unsaturated fatty acid decrease, this resulting in a lower unsaturation index than controls. Changes in CHS erythrocyte membrane lipids seem to be unrelated to serum lipid disorders as plasma lipid and apolipoprotein concentrations were apparently in the normal range, with the exception of a modest hypertriglyceridemia in patients and relatives and a decreased concentration of HDL cholesterol in patients. These findings indicate that CHS erythrocyte membranes contain an abnormal lipid matrix with which membrane proteins are defectively associated. The anomalous CHS membrane composition can be explained on the postulated effects of the CHS1/Lyst gene.

Features of severe periodontal disease in a teenager with Chédiak-Higashi syndrome.

BACKGROUND: Chédiak-Higashi syndrome (C-HS) is a rare congenital disease characterized by defective neutrophil function with abnormal lysosomal inclusions, neutropenia, and reduced chemotaxis. The complete syndrome includes oculocutaneous albinism with photophobia, neurologic features, recurrent infections, and enterocolitis. METHODS: A 14-year-old male C-HS patient was referred to us because of serious periodontal destruction with acute inflamed gingiva and ulcers. Clinical and biological investigations were performed, leading to the diagnosis of C-HS. RESULTS: Laboratory findings included neutropenia and hypergammaglobulinemia. Peripheral blood smears showed giant granules in neutrophils, eosinophils, and granulocytes. Bone marrow smears showed giant inclusions in leukocyte precursor cells. These granules and inclusions were characteristic of Chédiak-Higashi syndrome. Oral radiographic status showed extensive loss of alveolar bone leading, in most cases, to tooth exfoliation. Bacteria often associated with periodontitis were detected in subgingival plaque samples, including Fusobacterium nucleatum, Campylobacter rectus, Prevotella melaninogenica, Peptostreptococcus anaerobius, and Clostridium sp. Biopsies of periodontal tissues for light and electronic microscopic examinations revealed massive bacterial invasion of the epithelial tissue, epithelial cells, and connective tissue. Ultrastructural observations of periodontal polymorphonuclear leukocytes showed defective granulation, with abnormal granules not discharging their lysosomal content against engulfed bacteria. Viable dividing bacteria were found in the cytoplasm. CONCLUSIONS: In this case, early-onset periodontitis seems to be the expression of C-HS granulocyte deficiency. Periodontal treatment of these patients is often unsuccessful. This case report illustrates the importance of the dentist in initiating clinical and biological investigations in such early aggressive periodontitis in young patients.

Chediak-Higashi syndrome mutation and genetic testing in Japanese black cattle (Wagyu).

Chediak-Higashi Syndrome (CHS) is an autosomal recessive disorder that affects several species including mice, humans, and cattle. Evidence based on clinical characteristics and somatic cell genetics suggests that mutations in a common gene cause CHS in the three species. The CHS locus on human chromosome 1 and mouse chromosome 13 encodes a lysosomal trafficking regulator formerly known as LYST, now known as CHS1, and is defective in CHS patients and beige mice, respectively. We have mapped the CHS locus to the proximal region of bovine chromosome 28 by linkage analysis using microsatellite markers previously mapped to this chromosome. Furthermore, we have identified a missense A:T-->G:C mutation that results in replacement of a histidine with an arginine residue at codon 2015 of the CHS1 gene. This mutation is the most likely cause of CHS in Wagyu cattle. In addition, we describe quick, inexpensive, PCR based tests that will permit elimination of the CHS mutation from Wagyu breeding herds.

[The Chediak-Higashi syndrome]. / Sindrom Chediaka--Khigashi.

The Chediak-Higashi syndrome is described. The morphology of the blood and bone marrow in a girl aged 4.5 months [correction of years] is described in detail. Hematological, immunological, and karyological characteristics of her parents are presented.