Detection of mutant protein in complex biological samples: glucocerebrosidase mutations in Gaucher's disease

We report a sensitive method to detect point mutations in proteins from complex samples. The method is based on surface-enhanced laser desorption/ionization time-of-flight (SELDI-ToF) MS but can be extended to other MS platforms. The target protein in this study is the lysosomal enzyme glucocerebrosidase (GC), the key enzyme in Gaucher's disease. Deficiency of GC activity results in accumulation of glucosylceramide in macrophages. The relationship between GC genotypes and Gaucher's patient phenotypes is not strict. The possibility to measure protein levels of GC in clinical samples may provide deeper insight into the phenomenology of Gaucher's disease. For this purpose, GC was isolated in a single enrichment step through interaction with an immobilized monoclonal antibody, 8E4. After on-chip digestion of the antibody-antigen complex with trypsin, a total of 25 GC peptides were identified (sequence coverage approximately 60%), including several peptides containing mutated amino acid residues. The described methodology allows mutational analysis on the protein level, directly measured on complex biological samples without the necessity of elaborate purification procedures.     

Novel frameshift mutation (Pro171fsX21) in neonatal type 2 Gaucher's disease

Gaucher's disease is caused by a deficiency of glucocerebrosidase (GBA) and results in the accumulation of glucocerebroside within macrophages. We report on a 33(+2) gestational week premature infant whose family history was significant for a previously undiagnosed premature sibling with similar clinical features, including severe hydrops fetalis, hepatosplenomegaly, skin lesions at birth followed by death. The diagnosis of Gaucher's disease type 2 in the present case was based on postmortem pathological findings and a subsequent gene analysis that indicated a heterozygous condition for the novel deletion mutation at GBA cDNA nucleotide position 630 resulting in the frameshift (Pro171fsX21) in exon 6 and a G→A transition mutation at GBA cDNA nucleotide position 887 (Arg257Gln) in exon 7.     

Monoclonal gammopathies of undetermined significance

The term 'monoclonal gammopathy of undetermined significance' denotes the presence of a monoclonal protein in patients without evidence of multiple myeloma, macroglobulinemia, amyloidosis or related plasma cell proliferative disorders. The disorder has been found in approximately 3% of persons older than 70 years and in approximately 1% of persons older than 50 years. A population-based study included 1384 patients from south-eastern Minnesota who had the disorder diagnosed at the Mayo Clinic from 1960 through 1994. Risk of progression was about 1% per year, but patients were at risk of progression even after 25 years or more of stable monoclonal gammopathy of undetermined significance. The risk for development of multiple myeloma was increased 25-fold; the risk of macroglobulinemia, 46-fold; and the risk of primary amyloidosis, 8.4-fold. Concentration and type of monoclonal protein were the only independent predictors of progression. The presence of a urine monoclonal protein and the reduction of one or more uninvolved immunoglobulins were not risk factors for progression. Monoclonal gammopathy of undetermined significance may be associated with various disorders, including lymphoproliferative diseases, leukemia, von Willebrand disease, connective tissue diseases and neurologic disorders.     

Immunochemical and ultrastructural investigations in a patient with cold-agglutinine-active monoclonal IgMK-gammopathy.

A patient with "chronic cold-agglutinin disease" is described. Initially, the process was a benign monoclonal gammopathy. After an intervall of 6 years clinical, cytomorphological and immunochemical studies showed progress towards malignancy. In the bone marrow intranuclear lipid-like inclusions appeared in the plasma cells.     

Differences in immunoglobulin light chain species found in urinary exosomes in light chain amyloidosis (Al)

Renal involvement is a frequent consequence of plasma cell dyscrasias. The most common entities are light chain amyloidosis, monoclonal immunoglobulin deposition disease and myeloma cast nephropathy. Despite a common origin, each condition has its own unique histologic and pathophysiologic characteristic which requires a renal biopsy to distinguish. Recent studies have shown urinary exosomes containing kidney-derived membrane and cytosolic proteins that can be used to probe the proteomics of the entire urinary system from the glomerulus to the bladder. In this study, we analyzed urine exosomes to determine the differences between exosomes from patients with light chain amyloidosis, multiple myeloma, monoclonal gammopathy of undetermined significance, and non-paraproteinemia related kidney disease controls. In patients with light chain amyloidosis, multiple myeloma and monoclonal gammopathy of undetermined significance, immunoreactive proteins corresponding to monomeric light chains were found in exosomes by western blot. In all of the amyloidosis samples with active disease, high molecular weight immunoreactive species corresponding to a decamer were found which were not found in exosomes from the other diseases or in amyloidosis exosomes from patients in remission. Few or no light chains monomeric bands were found in non-paraproteinemia related kidney disease controls. Our results showed that urinary exosomes may have tremendous potential in furthering our understanding of the pathophysiology and diagnosis of plasma cell dyscrasia related kidney diseases.     

Tight linkage between type III Gaucher's disease (Norrbottnian type) and a MspI polymorphism within the gene for human glucocerebrosidase

A MspI polymorphism was detected in the beta-glucocerebrosidase gene in 10 Swedish families affected by type III Gaucher's disease. The sizes of the polymorphic fragments were 1.70 and 1.75 kb and the disease was found to segregate with the 1.70-kb fragment in 32 meioses. Only the 1.75-kb fragment was detected in families with no history of Gaucher's disease. The results indicate that the mutation causing type III Gaucher's disease has occurred once within the Swedish population. The polymorphism is useful for carrier detection since biochemical tests sometimes give inconclusive results.     

Comparison of rates of hydrolysis of N-oleoyl and N-stearoyl glucocerebroside in patients with Gaucher's disease

The deficiency of oleic acid as one of the fatty acids in glucocerebrosides that accumulate (31--77 mg/g dry weight) in the spleen in patients with Gaucher's disease was confirmed in 9 cases. In an effort to account for the 10-fold difference between the oleoyl glycocerebroside content of glucocerebrosides in spleen from controls and patients with Gaucher's disease, we compared the ability of extracts of spleen and fibroblasts from individuals with various forms of Gaucher's disease and controls to hydrolyze [14C]stearoyl and [3H]oleoyl glucocerebroside. The residual glucosylceramidase activity in patients with Gaucher's disease hydrolyzes the glucose moiety of oleoyl glucocerebroside at approximately the same rate as that of stearoyl glucocerebroside. Similarly, the more active glucosylceramidase of control tissue acts upon both oleoyl and stearoyl glucocerebrosides with equal efficiency. These observations indicate that a mutation affecting the substrate specificity of glucosylceramidase cannot account for the lack of oleic acid-containing glucocerebrosides in patients with Gaucher's disease. Thus, the hypothesis that the difference in fatty acid composition found in glucocerebroside is obtained as a result of a mutation affecting the specificity of the residual glucosylceramidase must be rejected.     

Bone-marrow plasmocytosis--an immunohistological study

Bone-marrow biopsies and smears from 59 patients with reactive plasmocytosis (22), multiple myeloma (24), solitary plasmocytoma (3) and monoclonal gammopathy of undetermined significance (MGUS) (10) were examined. To demonstrate cytoplasmic immunoglobulin the immunoperoxidase method was applied and evaluated quantitatively. Immunohistology yielded different ranges in kappa/lambda ratio for reactive plasmocytosis (0.4-3.5), multiple myeloma (less than or equal to 0.1 and greater than or equal to 11.2) and MGUS (0.2-3.0). As a result this method seems to be helpful in characterizing a plasmocytosis and distinguishing overt myeloma from monoclonal gammopathy of undetermined significance and reactive plasmocytosis. A differentiation of monoclonal gammopathy of undetermined significance from reactive plasmocytosis is not possible histologically and immunohistologically.     

Monoclonal gammopathy in chronic myeloproliferative disorders

The incidence of monoclonal gammopathy in 61 patients with chronic myeloproliferative disorders (CMPD) was studied. The distribution of patients among the CMPD subgroups was: chronic myelocytic leukemia, 24 patients; myelofibrosis, 11; polycythemia vera, 15; essential thrombocythemia, 7; unclassified MPD, 4 patients. Monoclonal gammopathy was found in 5 patients (8.2%). Two of these patients (1 IgA/k and 1 IgM/k) had myelofibrosis and 3 (2 IgG/k and 1 IgG/lambda) polycythemia vera. The presence of monoclonal gammopathy indicates an involvement of the lymphoplasmatic system in CMPD.     

Pituitary Macroadenoma in a Patient with Poems Syndrome in Conjunction with Castleman Disease: First Report of a Case and Review of Related Literature

ObjectiveTo describe the first reported case of a patient with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) in conjunction with the endocrinologic manifestation of panhypopituitarism due to a large clinically nonfunctioning pituitary adenoma.MethodsWe present the clinical, laboratory, and radiologic details of the case and review the relevant updated literature.ResultsA 48-year-old man with hypopituitarism and progressive polyneuropathy presented to an outside hospital with confusion and diaphoresis. He also had diffuse lymphadenopathy, monoclonal gammopathy, and skin lesions consistent with a diagnosis of POEMS syndrome. Cytopathologic study of a lymph node showed findings consistent with Castleman disease. A large suprasellar mass was found to be the cause of the hypopituitarism.ConclusionPOEMS syndrome is a rare paraneoplastic condition, commonly associated with Castleman disease, that manifests with progressive distal polyneuropathy and a monoclonal plasma cell disorder, often accompanied by endocrinopathy, organomegaly, skin changes, sclerotic bone lesions, ascites, erythrocytosis, and thrombocytosis. Our current patient had all 5 classic features of POEMS syndrome along with some diagnostic elements of Castleman disease, sclerotic bone lesions, and thrombocytosis. To our knowledge, this is the first known reported case of a patient whose endocrinologic manifestation of POEMS syndrome was panhypopituitarism attributable to a large clinically nonfunctioning pituitary adenoma. (Endocr Pract. 2010;16:97-101)     

Gaucher's disease in an infant diagnosed by fine needle aspiration of the liver and spleen. A case report.

A case of Gaucher's disease diagnosed by means of fine needle aspiration of the liver and spleen in a 12-month-old boy with hepatosplenomegaly is presented. The diagnosis was based on the finding of large, macrophagelike cells with abundant, pale, fibrillary cytoplasm and small nuclei. The patient had no family history of Gaucher's disease, and the diagnosis was not suspected clinically.     

Variability of plasma viscosity in monoclonal IgM gammopathies.

Hyperviscosity syndromes can caused by both plasmatic and cellular factors. We have studied 20 patients affected by IgM gammopathy of different origin and 12 healthy subjects matched for sex and age, in order to evaluate the relation between paraprotein levels and plasma viscosity. We have observed a significant plasma viscosity increase only in 14 patients with monoclonal IgMk gammopathy. In the same patients was also evident an hyperviscosity syndrome. In the other 6 patients, with monoclonal IgM or polyclonal gammopathy and without clinical symptoms, plasma viscosity was only slightly increased. We have also observed a significant correlation between IgM and light chains (kappa, lambda) serum level and increased plasma viscosity. These results suggest that one can't consider all IgM gammopathies as cause of hyperviscosity syndrome.     

Sucrose gradient analysis of phospholipid-activated beta-glucosidase in type 1 and type 2 Gaucher's disease

Using sucrose density gradients, differences in delipidated lysosomal beta-glucosidase isolated from control spleen and spleen from patients with nonneurologic (type 1) and neurologic (type 2) Gaucher's disease have been examined. The three enzymes differ in sedimentation properties as well as in their responsiveness to activation by phosphatidylserine and heat-stable factor. The control beta-glucosidase sedimented as an apparent 45,000-Da species whose activity was dependent upon the inclusion of exogenous sodium taurodeoxycholate in the assay medium. Preincubation with a mixture of phosphatidylserine and heat-stable factor converted the control enzyme to a faster-sedimenting form which exhibited considerable activity in the absence of exogenous bile salt. Spleen beta-glucosidase from a patient with type 1 Gaucher's disease exhibited an apparent molecular weight of 154,000 on sucrose gradients. Like the control enzyme, the activity of this form was bile salt dependent. Upon preincubation with phosphatidylserine and heat-stable factor, beta-glucosidase from the type 1 case was also converted to a faster-sedimenting form which was more active in the absence of sodium taurodeoxycholate than in the presence of the bile salt. Spleen beta-glucosidase from the patient with type 2 Gaucher's disease sedimented as a broad peak of activity in the most dense regions of the sucrose gradients, appearing to be much larger than the beta-glucosidase from either the control or the type 1 Gaucher's disease patient. The activity of this large species was strongly dependent upon bile salt, and was not affected by preincubation of the enzyme with phosphatidylserine and heat-stable factor. Using the chaotropic salt, sodium thiocyanate (0.15 M), the spleen beta-glucosidase isolated from the type 1 Gaucher's disease case was converted to a slower-sedimenting species. The control enzyme sedimented slightly farther into the sucrose gradients upon treatment with the NaSCN. Thiocyanate treatment had no effect on the spleen beta-glucosidase isolated from the case of type 2 Gaucher's disease.     

Frequent association of idiopathic myelofibrosis with plasma cell dyscrasias

In a retrospective analysis of 199 cases of myeloproliferative diseases a concomitant plasma cell dyscrasia was found in three out of 46 patients with idiopathic myelofibrosis. Chronic myeloid leukemia, polycythemia vera or unclassifiable myeloproliferative disorders were in no case associated with monoclonal gammopathy. One patient with idiopathic myelofibrosis had primarily coexistent IgG-lambda paraproteinemia and increasing osteolytic lesions; histologic evidence of multiple myeloma, however, was insufficient. In the second patient the interval between diagnosis of idiopathic myelofibrosis and IgG-kappa paraproteinemia was 11 years. After a stable period of 9 years' duration the paraprotein level rapidly increased, associated with depression of normal background immunoglobulins and progressive bone marrow failure. The exact nature of this patient's malignant plasma cell dyscrasia remained uncertain. In the third case benign monoclonal gammopathy of the IgM-lambda type was diagnosed 13 years after idiopathic myelofibrosis. A review of the literature confirms a remarkably high incidence of monoclonal gammopathies in idiopathic myelofibrosis. Benign monoclonal gammopathy seems to occur in at least 8% of the patients while only a few cases of concomitant multiple myeloma have been reported. It may be speculated that plasma cell dyscrasias in idiopathic myelofibrosis reflect involvement of the lymphoid lineage in the neoplastic stem cell disorder.     

The monoclonal gammapathy of uncertain meaning- a premyelomatosis?

In three cases of localised multiple myeloma the monoclonal immunoglobulin could be identified even 17, 12 and 8 years prior to clinical manifestation. These observations point again to the question of a possible "history of development" for the plasma cell disease and, thus, to the clinical validity of monoclonal gammopathy of (still) uncertain significance. As even in the relationship of membrane-associated light chains of B-lymphocytes a certain monoclonality begins to appear at an early time, more attention should be devoted to the early diagnosis of malign plasma cell dyscrasia.     

Plural light chains in a single plasma cell of a monoclonal gammopathy undetermined significance case: An ultrastructural study

A 44-year-old man was found to have M-proteins of IgG consisting of kappa- and lambda-chains in serum without lymphadenopathy or splenomegaly. The serum concentrations of IgG, IgA and IgM were within normal limits. Bone marrow examination showed normal cellular marrow containing 6.3% of plasma cells with no abnormal features. No chromosomal abnormality was observed at all. The patient was diagnosed as having monoclonal gammopathy of undetermined significance. The bone marrow plasma cells possessed free kappa- and lambda-chains in Golgi apparatus, rough endoplasmic reticula and cytoplasmic matrices. Plural light chains were simultaneously produced with the same heavy chain in a plasma cell by immunoelectron microscopy. This is the first report in the world of a monoclonal gammopathy of undetermined significance producing plural light chains with the same heavy chain.     

Effect of chemotherapy on T-lymphocyte subsets in B-cell proliferative disorders

The T-cell subset distribution and the activity markers of 41 patients with multiple Myeloma, Waldenstr?m's macroglobulinaemia and benign monoclonal gammopathy were repeatedly analysed using monoclonal antibodies (T3, T4, T8, anti-TAC, anti DR) and rosetting techniques. In myeloma and macroglobulinaemia the relative and absolute numbers of T4+ cells were diminished while the absolute number of T8+ cells was not decreased. No significant difference between stage I and III of the myeloma disease was seen. The diminished number of T4+ cells in myeloma was partly due to the effect of chemotherapy. Chemotherapy-induced lymphopenia resulted in a drop of circulating T4+ cells and an inverted T4/T8 cell ratio. Untreated patients with myeloma were not significantly different from patients with benign gammopathy. Patients with macroglobulinaemia differed from patients with myeloma as they had an increased absolute T8 cell count and a significantly elevated percentage of TAC+ (= IL 2 receptor expressing) cells. In macroglobulinaemia chemotherapy affected also the T8+ cell subset. Thus, patients with macroglobulinaemia, but not with myeloma appear to have activated T8+ cells in their circulation.     

Clinical effectiveness of desmopressin in a case of acquired von Willebrand's syndrome associated with benign monoclonal gammopathy

A case of acquired von Willebrand's syndrome (avWs) secondary to benign monoclonal gammopathy, is described, in which desmopressin (DDAVP) has proven effective repeatedly in preventing bleeding after tooth extraction. The laboratory pattern was similar to that of congenital type IA von Willebrand's disease. After DDAVP, prolonged bleeding time and factor VIII/von Willebrand factor activities were normalized. The disappearance rate of the elicited activities was similar to that observed in patients with congenital disease. This report adds to the scarce data concerning the haemostatic effectiveness of DDAVP in avWs and suggests that this agent might also be used in controlling or preventing bleeding in patients with the acquired disease, selected on the basis of their biological responsiveness to a test-infusion.     

Some histochemical observations on Gaucher cells

Plastic-embedded bone marrow biopsies from four patients with Gaucher's disease have been studied histochemically. Concanavalin A (ConA) was found to bind to cytoplasmic inclusions of Gaucher cells; the binding was prevented by lipid extraction or beta-glucosidase digestion. This suggests that glucocerebrosides stored in Gaucher cells are responsible for ConA binding; ConA staining combined with lipid extraction and beta-glucosidase digestion tests may be taken as a tool for the demonstration of Gaucher's cerebrosides of possible practical importance in diagnosis and investigation of Gaucher's disease. An excess of vic-glycol groups with respect to ConA binding-sugar residues and not extractable by lipid solvents are demonstrable in Gaucher cells. Vic-glycols appear to be regularly arranged at the electron microscopy level within Gaucher cell lysosomes along typical Gaucher "tubules", where some kind of interaction between lipid and protein should occur. Acid phosphatase might be one protein species involved in such interaction.     

Differential effects of glycolipid biosynthesis inhibitors on ceramide-induced cell death in neuroblastoma cells

An in vitro model of Gaucher's disease in murine neuroblastoma x rat glioma NG108-15 cells was used to investigate the physiological effects of two specific inhibitors of glucosylceramide synthase, d,l-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (d,l-PDMP) and N-butyldeoxynojirimycin (NB-DNJ), which have been suggested as agents for treatment of glycolipid storage disorders. Incubation of NG108-15 cells with conduritol-B-epoxide, a covalent inhibitor of glucosylceramidase, raised the intracellular concentration of glucosylceramide (GC) by more than fourfold, indicating a glycolipid composition equivalent to that of Gaucher's cells. The level of GC was decreased, and the cells were depleted of gangliosides by postincubation with d,l-PDMP or NB-DNJ. Treatment with d,l-PDMP, but not with NB-DNJ, resulted in a dose-dependent reduction of the growth rate and eventually caused cell death in NG108-15 cells on reaching confluency. An in situ detection assay using terminal nucleotidyltransferase indicated that cell degeneration was accompanied by apoptosis. Lipid analysis by high-performance TLC revealed that on incubation with d,l-PDMP, but not with NB-DNJ, the concentration of endogenous ceramide was elevated by threefold. Ceramide elevation and apoptosis were also observed when NG108-15 cells were incubated with daunorubicin, which was previously reported to induce programmed cell death by stimulation of ceramide synthesis. Structural characterization by HPLC and subsequent laser desorption mass spectrometry revealed that the endogenous ceramide contained fatty acids with chain lengths ranging from C14:0 to C24:0. The results indicate that elevation of levels of these ceramide species by incubation with d,l-PDMP or daunorubicin induces programmed cell death in NG108-15 cells. Because ceramide accumulation and cell death were not observed on incubation with NB-DNJ, its use is suggested to be less toxic than that of d,l-PDMP for treatment of Gaucher's disease and other sphingolipid storage disorders.