Heterozygote detection of type I Gaucher disease using blood platelets

This report describes a reliable and reproducible method for the identification of carriers of Type I Gaucher disease using blood platelets as the source of beta-glucosidase and 4-methylumbelliferyl-beta-D-glucoside as substrate. Platelet lysates have at least two identifiable beta-glucosidase activities with the synthetic substrate. One is maximally active at pH 5.0 in the absence of sodium taurocholate and the other at pH 5.6 in the presence of taurocholate. In platelets of Gaucher homozygotes and heterozygotes, the beta-glucosidase activity at pH 5.6 with the bile salt is reduced whereas the activity at pH 5.0 is the same in non-carriers, carriers and affected patients. In addition to differences in specific activity, the ratio of beta-hexosaminidase to beta-glucosidase activities is a useful parameter in the evaluation of the carrier state. Since carriers have normal activity of hexosaminidase and a reduced activity of beta-glucosidase, their mean activity ratio is about 70% higher than in non-carriers. Therefore we propose that the specific activity of beta-glucosidase at pH 5.6 in the presence of sodium taurocholate with the ratio of beta-hexosaminidase to beta-glucosidase serve as useful and reliable indices in the evaluation of the carrier state for Gaucher disease.

[Phenotypes in heteroglycanoses and sphingolipidoses (author's transl)]

Sphingolipidoses and heteroglycanoses are inborn errors of the carbohydrate metabolism. Biochemically and clinically hetero-glycanoses are sub-divided into mucopolysaccharidoses, oligosaccharidoses and mucolipidoses. These disorders of complex carbohydrate metabolism are due to the inborn defect of one or more lysosomal enzymes which in turn cause an intracellular accumulation of not-degraded complex carbohydrates corresponding to a wide pattern of clinical expression and symptomatology ranging from psychomotor retardation without any dysmorphic signs to severe features of a storage disease with dwarfism, peculiar facial appearance, organomegaly and skeletal changes. Investigations of recent years revealed that there is tremendous phenotypic variation even within diseases caused by a deficiency of the same enzyme. On the other hand, clinically indistinguishable phenotypes may be caused by the defect of different enzymes.

[Prenatal diagnosis of Gaucher's disease (author's transl)]

Gaucher's disease type I was diagnosed prenatally in one case. Using radiomarked natural lipid substrate the enzyme defect was demonstrated in amniotic cells cultured after amniocentesis in the 16th week of pregnancy. Rest activity of cerebroside beta-glucosidase was around 6% of control activity. After termination of pregnancy in the 19th week the diagnosis was confirmed in the fetus by demonstration of lack of enzyme activity in fetal fibroblasts and liver tissue. Enzyme levels of cerebroside beta-glucosidase in blood leucocytes of the couple who decided on termination of the pathological pregnancy were found compatible with but no proving the heterozygote state of Gaucher's disease. In the future the enzyme defect of affected probands should be determined early and as precisely as possible.

Assay of the beta-glucosidase activity with natural labelled and artificial substrates in cultivated skin fibroblasts from homozygotes and heterozygotes with the Norrbottnian type of Gaucher disease

Fibroblasts from 13 homozygotes and 27 obligate heterozygotes with the Norrbottnian type of Gaucher disease and 17 controls were cultivated and assayed with five beta-glucosidase methods, two with D-[glucose-U-14C] glucosylceramide and three with the artificial substrate 4-methylumbelliferyl-beta-glucoside. Two marker enzymes were assayed on the same cell samples, 4-methylumbelliferyl-beta-galactosidase and N-acetyl-beta-glucosaminidase. The beta-glucosidase activity of cultured fibroblasts, as measured with all five beta-glucosidase methods, was significantly lower (P < 0.001) for Gaucher homozygotes than heterozygotes. There was no overlap between fibroblasts from Gaucher homozygotes and the others with any of the beta-glucosidase methods used. The beta-glucosidase activity was also significantly lower (P < 0.001) for Gaucher heterozygotes than controls. However, none of the five beta-glucosidase assays differentiated between all Gaucher heterozygotes and controls, as several overlaps occurred in each assay.

Assay of the beta-glucosidase activity with natural labelled and artificial substrates in leukocytes from homozygotes and heterozygotes with the Norrbottnian type (Type 3) of Gaucher disease

Leukocytes were isolated from 14 patients (7 males and 7 females ) with Gaucher disease of the Norrbottnian type (Type 3), 32 obligate heterozygotes (16 males and 16 females) for this disease and 20 controls (10 males and 10 females). After collection, the cells were transported in dry ice to the laboratory, where they were assayed. The assays were repeated after the cells had been stored for 12 months. beta-Glucosidase activity was assayed with D-[glucose-U-14C]glucosylceramide at pH 5.8 with Cutscum-Na-cholate as a detergent and 4-methylumbelliferyl-beta-glucoside at pH 4.1 with Triton-Na-taurocholate as a detergent. The activities of two marker enzymes, 4-methylumbelliferyl-beta-galactosidase and N-acetyl-beta-glucosaminidase, were assayed in aliquots of the same leukocyte samples. The activity of beta-galactosidase remained constant during storage, N-acetyl-beta-glucosaminidase increased, while beta-glucosidase decreased as assayed with the natural as well as with the artificial substrate. beta-Glucosidase activity was significantly lower in the female than in male controls and heterozygotes. When assayed with natural substrate beta-glucosidase activity in leukocytes from the male patients was 6--12% of the control mean value and 10--15% in those from the female patients. The corresponding figures found when the artificial substrate was used were 15--30% and 22--45%. The values for the heterozygotes were respectively 42--68% and 34--79% with the natural substrate, and 33--82% and 51--109% with the artificial substrate. No correlation was found between the age of the patient and the beta-glucosidase activity.

A modified method for the identification of heterozygotes for Gaucher's disease using differential thermal inactivation

We have found heat inactivation of leukocyte 4-methylumbelliferyl-beta-D-glucosidase to be useful in identifying heterozygotes for adult (chronic) Gaucher's disease. The overlap between high heterozygote values and low normal values is reduced by the heat inactivation step, compared to assays without heating; that is from an overlap of 23% to 6%. Although preliminary, our results indicate that this procedure may be useful in families with adult (chronic) Gaucher's disease.

Diagnosis of adult Gaucher disease: use of a new chromogenic substrate, 2-hexadecanoylamino-4-nitrophenyl-beta-D-glucopyranoside, in cultured skin fibroblasts

Gaucher disease is a group of lipid storage diseases in which the glycosphingolipid glucocerebroside accumulates in tissues because of deficiency of the enzyme glucocerebrosidase. Radioactively labelled glucocerebroside and the artificial fluorogenic substrate 4-methylumbelliferyl-beta-D-glucopyranoside are commonly used for its diagnosis. We studied the use of a new chromogenic substrate, 2-hexadecanoylamino-4-nitrophenyl-beta-D-glucopyranoside in cultured skin fibroblasts. The amount of reaction product, 2-hexadecanoylamino-4-nitrophenol, increased linearly with incubation time for at least 4 h and was proportional to the amount of fibroblast protein added up to 150 micrograms per incubation. The pH optimum was 4.8. The Km was 0.19 mmol/l. The mean activity of control cultured skin fibroblasts was 22.9 +/- 5.4 nmol of product formed per mg fibroblast protein per hour under standard conditions. Cultured skin fibroblasts from patients with adult non-neuropathic Gaucher disease had reduced activity, 6.4 +/- 2.4 nmol/mg/h or 28% of control activity. This compared well with mean enzyme activity in the same patients determined using the natural substrate, [14C]glucocerebroside: 28% of control activity. Heterozygotes had reduced activity with the new substrate.

Gaucher's disease: a clinical, morphological and biochemical study of a Nigerian family

Two Nigerian sibling presented with progressive hepato-splenomegaly in infancy from which they subsequently died. Morphological investigations carried out showed that the children had Gaucher's disease. Leucocyte B-glucocerebrosidase activities from the parents of the two siblings and also from one surviving sibling were found to be only about 50% of the enzyme activities in control subjects while hexosaminidase and B-glucuronidase activities were within normal limits. There results showed that the three surviving relatives are heterozygotes and also provided a strong supporting evidence that the deceased children had Gaucher's disease. The occurence of this disease in African children living in Kenya, Uganda, the Congo and Nigeria, and in Black Americans suggest that this biochemical abnormality is not as rare in the Negroid race as has been believed hitherto, and may be widespread on the African continent.

Leukocyte beta-glucosidase in homozygotes and heterozygotes for Gaucher disease

Human leukocytes contain at least two isozymes of 4-methylumbelliferyl-beta-glucosidase acting optimally at pH 4.0 and 4.8; in Gaucher disease, only the former is deficient. Brief exposure of the leukocyte homogenate to pH 4.0 at room temperature results in irreversible inactivation of the pH 4.8 activity, while the activity at pH 4.0 remains unaffected. The more acidic isozyme is stimulated four- to fivefold by 0.2% sodium taurodeoxycholate (TDC) with a shift in the pH optimum to 5.0. The less acidic isozyme is completely suppressed in the presence of this detergent. Both leukocyte isozymes appear to be membrane-bound since gel filtration of Sephadex G-200 produces only one peak of activity located at the void volume, unlike in liver and kidney where a second peak also can be demonstrated. Heat inactivation analysis indicated that in controls, assayed in the absence of detergent, pH 4.0 activity is more thermostable than pH 4.8 activity. However, in Gaucher disease, the residual beta-glucosidase at pH 4.0 is just as thermolabile as the unaffected pH 4.8 activity. Heat inactivation of the enzyme in the presence of TDC resulted in rapid loss of activity, suggesting a direct effect of the bile salt on the configuration of the enzyme decreasing its thermal stability. In the absence of detergent, acid beta-glucosidase shows two K(m)'s, one at 3.2 mM and another at 0.9 mM. In the presence of detergent, only the higher K(m) at 3.3 mM is obtained. In patients with Gaucher disease and in obligate carriers, the K(m) remains essentially unaffected while the V(max) shows the expected deficiency.A reliable and reproducible selective assay technique has been developed for the diagnosis of Gaucher disease homozygotes and obligate heterozygotes and for the carrier screening of individuals at risk for this inherited disorder. The efficacy of this technique has been demonstrated by studying the activity in 42 controls, 26 patients, 32 obligate heterozygotes, and 23 healthy relatives of patients with Gaucher disease.

Gaucher disease--Norrbottnian type. I. General clinical description

We report follow-up studies of 22 cases of the Norrbottnian type of Gaucher disease ("type III"). The series was divided into 2 main groups of families depending on their birth province (Norrbotten, Västerbotten). The distribution and types of organ manifestations and complications were the same in both groups, each of which was considered to be genotypically homogeneous. The severity of the clinical symptoms and signs and the course of the disease differed markedly not only between families but also between siblings. Splenectomy accelerated deterioration, particularly with regard to skeletal and central nervous system manifestations. On a clinical basis it is concluded that the Norrbottnian type of Gaucher disease, which has now been diagnosed in about 40 cases, is probably due to a unique mutation which may have happened several hundred of years ago in northern Sweden.

Neurologic complications of Gaucher's disease, type 3

We discuss the clinical features of two patients with type 3 Gaucher's disease. Glucocerebroside levels in liver biopsy specimens were measured in both patients and the findings are discussed in regard to the pathogenesis of the disease.

Non-neuropathic Gaucher disease presenting in infancy

The non-neuropathic form of Gaucher's disease was diagnosed in 11 children of non-Jewish ancestry in South Africa; all were under the age of 4. None had any neurological involvement and, apart from the precocious presentation and rapid course, the features in each resembled those of the classical 'adult' or chronic non-neuropathic form of Gaucher disease. By contrast, the condition presented after puberty in 24 out of 28 Ashkenazi Jews who were studied during the same investigation. Activity of beta-glucosidase was defective in both groups of patients and they could not be distinguished by histological criteria. Only one child with the infantile neuropathic form of Gaucher disease was identified during the survey. The preponderance of the atypical non-neuropathic form of the disorder in young children is of practical importance from the point of view of differential diagnosis in any child with hepatosplenomegaly.

Gaucher's disease in South Africa

The adult non-neuropathic form of Gaucher's disease has been identified in 32 patients in 25 Ashkenazi Jewish kindreds in South Africa. The minimum prevalence in this population is 1 in 5000, with a gene frequency of 0.014 and a carrier rate of 1 in 36. On correction for bias resulting from possible under-ascertainment, these minimum figures become 1 in 4000, 0.0166, and 1 in 30, respectively. Confirmation of autosomal recessive inheritance was obtained by segregation analysis by the 'a priori' and 'simple sib' methods. The Ashkenazin of South Africa have their origins in Lithuania and it is evident that the high gene frequency in South Africa is a reflection of the genetic constitution of the immigrant population. The localisation of the Gaucher gene to Lithuania represents a further step in the determination of the early geographic distribution of the genetic disorders of the Jewish race.

Basic findings and current developments in sphingolipidoses

Sphingolipidoses are caused by recessively inherited deficiencies of lysosomal hydrolases. The clinical backgrounds of and current biochemical and genetic approaches to the different forms and variants of gangliosidoses, trihexosylceramidosis (Fabry's disease), galactosylceramidosis (Krabbe's disease), sulfatidoses (metachromatic leukodystrophies), glucosylceramidosis (Gaucher's disease), sphingomyelinoses (Niemann-Pick disease) and ceramidosis (Farber's disease) are presented.

Gaucher disease in the Afrikaner population of South Africa

The chronic non-neuropathic form of Gaucher disease has been encountered in 10 individuals in the Afrikaner population of South Africa. The minimum prevalence in this community is 1 in 200 000 with a gene frequency of 0,0022, a heterozygote rate of 0,0044 and at least 9 000 clinically asymptomatic carriers of the abnormal gene. This gene must be present in about 1 in every 220 Afrikaners. The majority of previously reported patients have been Ashkenazi Jews, in whom the condition is relatively benign. By contrast, the disorder in the Afrikaners is precocious in onset, with serious complications and rapid progression. The occurrence of Gaucher disease in a relatively high frequency in the Afrikaner population is important in terms of differential diagnosis, genetic counselling and prevention.

Familial psychosis and diverse neurologic abnormalities in adult-onset Gaucher's disease

A family is described in which adult-onset Gaucher's disease developed, followed years later by atypical psychotic disorders with neurologic and electroencephalographic abnormalities. A biochemical investigation of primary and secondary enzyme alterations in the index case was performed in an attempt to identify a pattern that might be specific to this clinical profile. The literature pertaining to CNS involvement in adult patients with Gaucher's disease is also reviewed. An etiologic link may exist between the inherited metabolic disorder and associated neuropsychiatric impairment. The biochemical basis of this hypothesized association remains unclear, however, and further enzymatic and pathologic investigations are warranted.

Primary amyloidosis associated with Gaucher's disease

Elevations in serum immunoglobulins, frequently monoclonal in nature, are known to occur in patients with the adult form of Gaucher's disease. We describe amyloidosis in a 46-year-old woman of Italian ancestry with Gaucher's disease, who also had 3100 mg/dl of monoclonal IgA. She died of restrictive cardiac disease. A 50-year-old sister, also with Gaucher's disease, had 1300 mg/dl of polyclonal IgM but no evidence of amyloidosis. A glucosyl sphingosine-Sepharose affinity column provided no evidence that the large amount of immunoglobulin present has specific affinity for glucosyl ceramide. This, to our knowledge, is the first report of amyloidosis complicating Gaucher's disease.

Amyloidosis. An unusual complication of Gaucher's disease

Gaucher's disease has been associated with plasma cell dyscrasias. A patient had Gaucher's disease, nephrotic syndrome, and systemic amyloidosis. Plasmacytosis in the bone marrow, the presence of light chains in the urine and renal glomeruli, and the finding of low circulating immunoglobulin levels suggest that the amyloid in this patient is related to a plasma cell dyscrasia.

In utero diagnosis of Gaucher disease

Beta-Glucosidase activity measured by synthetic substrate at pH 4.6 was low in the cultured amniotic cells from two pregnant women at risk for juvenile and adult type Gaucher disease. The diagnosis was confirmed by showing a low activity of beta-glucosidase in the skin fibroblasts with a synthetic substrate or in the spleen with a natural substrate, and by ascertaining the presence of Gaucher cells in the fetal tissues. However, considerable activity of beta-glucosidase measured with synthetic substrate was found in the liver of both affected fetuses and in the spleen of one. It is advisable that the determination of beta-glucosidase to confirm prenatal diagnosis of Gaucher disease be done either in the cultured skin fibroblasts or in the spleen, and if in the spleen, with a natural substrate rather than a synthetic one.

Clinical variation in 2 related children with neuronopathic Gaucher disease

The clinical features in 2 second cousins with neuronopathic Gaucher disease include slowly progressive ataxia, spasticity, myoclonus, and seizures with relative preservation of intellectual function. Organomegaly was noted only in Patient 1. Both patients had diffuse slowing with paroxysmal features in electroencephalograms and a deficiency of beta-glucosidase activity in leukocytes and skin fibroblast cultures. The parents of Patient 1 and the related father of Patient 2 had levels of beta-glucosidase activity consistent with the carrier state for Gaucher disease. The value of beta-glucosidase activity in the mother of Patient 2 suggests a different mutation, the result being a defective enzyme component not detectable by measuring total activity.

Synthetic substrate beta-glucosidase activity in leukocytes: a reproducible method for the identification of patients and carriers of Gaucher's disease

A method is described for the identification of patients and carriers of Gaucher's disease, using leukocytes from a small volume of blood. The fluorogenic substrate, 4-methylumbelliferyl-beta-D-glucopyranoside, was assayed in the presence of pure sodium taurocholate (2.5 mg/ml) and Triton X-100 (2.0 mg/ml). Some commercial brands of pure sodium taurocholate were satisfactory for this purpose. The pH optimum for controls, Gaucher disease carriers and Gaucher disease patients was 5.4 using citrate-phosphate buffer. Although leukocytes prepared from only a small amount of blood (2-8 ml) are required, there is sufficient quantity for measuring other lysosomal enzymes as controls. Using this method, 12 patients with all types of Gaucher's disease and 12 obligate heterozygotes were identified. Carrier status was predicted in six other family members and ruled out in six others. Eight unaffected people married to Gaucher carriers or Gaucher patients were predicted to be non-carriers of Gaucher's disease, thereby ruling out children affected with Gaucher's disease in that mating.

Juvenile Gaucher's disease with horizontal gaze palsy in three siblings

Three children in a West African family had Gaucher's disease of juvenile onset (Type 3), and all showed an identical neurological disorder. The diagnosis was substantiated by histochemical demonstration of Gaucher cells in bone marrow, liver, and spleen, the finding of an excess of glucosyl ceramides in a liver extract, and a deficient activity of the enzyme beta-glucosidase in cultured skin fibroblasts. The neurological picture was characterised by myoclonic epilepsy, muscle wasting, hypotonia, pyramidal signs, some intellectual deterioration, and a striking disturbance of eye movements. The latter appears to result from specific involvement of the supranuclear pathways subserving lateral gaze. The distinctive features of this clinical syndrome are emphasised.

Factor IX deficiency in Gaucher disease. An in vitro phenomenon

Low factor IX coagulant activity was demonstrated in a patient with Gaucher disease before and after splenectomy. The same abnormality was found in seven of ten additional patients studied. Possibly, abnormally retained sphingolipids inactivate or interfere with the action of certain procoagulants.

Infantile Gaucher's disease: glucocerebrosidase deficiency in peripheral blood leukocytes and cultured fibroblasts

A patient with infantile Gancher's disease is described. A marked decrease of the activity of beta-glucosidase at the lower pH 4.2 was found in peripheral blood leukocytes, whereas in cultured skin fibroblasts the activity at both pH'S 4.2 and 5.2 was decreased. Examining the leukocytes of the heterozygous parents the activities of beta-glucosidase at both pH's were within the values of controls, but the ratio's of activity of pH 5.2 to that at pH 4.2 were increased lying between the ratio's from the patient and controls.

Identity of 'acid' beta-glucosidase and glucocerebrosidase in human spleen

1. Glucocerebrosidase, in association with a membrane-bound ;acid' beta-glucosidase, was separated from a soluble ;neutral' beta-glucosidase that had no activity towards glucocerebroside as substrate. 2. Glucocerebrosidase, as well as ;acid' beta-glucosidase activity depended upon the association of factor P (a heat-stable, soluble, acidic glycoprotein) with factor C (a heat-labile membrane-bound protein). 3. Factor C was solubilized under certain conditions. 4. Solubilized factor C, as well as membrane-bound factor C, could be alternatively stimulated by sodium taurocholate to give both glucocerebrosidase and ;acid' beta-glucosidase activities. 5. Membrane-bound factor C reacted optimally with factor P whereas solubilized factor C was preferentially stimulated by taurocholate. 6. Factor P-dependent glucocerebrosidase activity differed in kinetic properties from the taurocholate-stimulated enzyme activity. 7. The results are discussed in the light of (a) identity of glucocerebrosidase and ;acid' beta-glucosidase, (b) application in clinical diagnosis, (c) physiological significance of the enzyme system, and (d) polygenic inheritance in adult Gaucher's disease.