Quality of life of patients with Fabry disease

This paper is the first of its kind to study the impact of Fabry disease (FD) in affected males, and shows that FD is associated with a significant decline in several domains. Using the medical outcomes study (MOS) SF-36 and a FD-specific questionnaire, we compared the observations found among these patients with that obtained for the general US population and other chronic disease states, including Gaucher disease (GD) (another lysosomal storage disorder), end-stage renal disease, stoke and AIDS. Patients with FD have a score profile most similar to patients with AIDS. In comparison with patients with GD, Fabry patients score substantially lower across all domains. Using simple linear regression, potential predictors of health-related quality of life (HRQOL) for Fabry patients were also determined. As in the general population, stroke, cardiac problems and renal disease lead to substantial decrement in HRQOL. In addition, two disease specific symptoms (acroparesthesia and anhidrosis) and pain are also predictors of decreased quality of life. Currently, no specific therapy for FD exists. As enzyme therapy for FD becomes increasingly available, it will be interesting to evaluate the therapy's impact on the quality of life of patients.

Fabry disease in genetic counseling practice: recommendations of the National Society of Genetic Counselors

The objective of this document is to provide health care professionals with recommendations for genetic counseling and testing of individuals with a suspected or confirmed diagnosis of Fabry disease, with a family history of Fabry disease, and those identified as female carriers of Fabry disease. These recommendations are the opinions of a multicenter working group of genetic counselors, medical geneticists, and other health professionals with expertise in Fabry disease counseling, as well as an individual with Fabry disease who is a founder of a Fabry disease patient advocacy group in the United States. The recommendations are U.S. Preventive Task Force Class III, and they are based on clinical experience, a review of pertinent English-language articles, and reports of expert committees. This document reviews the genetics of Fabry disease, the indications for genetic testing and interpretation of results, psychosocial considerations, and references for professional and patient resources. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a healthcare provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.

Rapid detection of the two common mutations in Ashkenazi Jewish patients with mucolipidosis type IV

Among Ashkenazi Jewish individuals with mucolipidosis IV (ML IV), two mutations in the ML IV gene, IVS3-1A --> G and delEX1-EX7, account for more than 95% of disease alleles. The reported method of genotyping for the delEX1-EX7 mutation involves a cumbersome multistep procedure. In the present study, a new simplified one-step procedure is described that detects this mutation in both patients and carriers. An improved procedure is also described for detection of the IVS3-1A --> G mutation. Using these improved procedures, we have characterized the ML IV mutant alleles in 27 patients and 95 of their relatives from 22 families, and in 123 unrelated and unaffected Ashkenazi Jewish controls. Of the 27 ML IV patients, 16 patients (59.3%) were found to be homozygous for the IVS3-1A --> G mutation and 1 patient (3.7%) homozygous for the delEX1-EX7 mutation. Additionally, 9 patients (33.3%) were compound heterozygotes for IVS3-1A --> G/delEX1-EX7. Among the 123 Ashkenazi Jewish controls, two individuals were identified as heteroallelic with one IVS3-1A --> G mutation (carrier frequency: approximately 1 in 61); none showed the delEX1-EX7 mutation. The modifications described here provide a more facile means of genotyping patients and carriers and expand the possibilities for screening at-risk populations.

Advances in the management of Anderson-Fabry disease: enzyme replacement therapy

Anderson-Fabry disease (AFD) is a lysosomal storage disorder (LSD) due to alpha-galactosidase A (alpha-Gal A) deficiency and the resultant accumulation of incompletely metabolised glycosphingolipids (GSLs), primarily globotriosylceramide (Gb(3)), within various tissues. It is an X-linked multisystem disorder characterised by progressive renal insufficiency, with added morbidity from cardio- and cerebrovascular involvement, and associated with significant impact on quality of life and diminished lifespan. The disease manifests primarily in hemizygous males; however, there is increasing recognition that heterozygous (carrier) females may also develop disease-related complications, although onset among affected women may be delayed. Until recently, treatment has been limited to symptomatic management of pain and other measures to alleviate the problems associated with end-stage complications from renal, cardiac and nervous system involvement. The availability of the recombinant enzyme offers the potential of a safe and effective targeted treatment approach. At the moment, two distinct enzyme formulations are approved in Europe (and in other countries) and both continue to undergo FDA evaluation in the US. Increasing knowledge of the natural history of AFD and greater experience with enzyme therapy should enable optimal patient care. The relative rarity and complexity of AFD necessitates a multi-disciplinary team approach that may be facilitated by a centralised registry.

Patients with Fabry disease on dialysis in the United States

BACKGROUND

: Fabry disease results from an X-linked deficiency of lysosomal alpha-galactosidase A and is a rare cause of end-stage renal disease. Little is known about the characteristics of patients with Fabry disease that initiate dialysis in the United States, although data from Europe suggests these individuals have a poor survival.

METHODS

: Using the United States Renal Disease System database, we first studied in detail 42 Fabry patients who initiated dialysis between April 1995 (following the introduction of the new detailed HCFA 2728 form) and July 1998. To examine crude survival in a larger cohort, 95 Fabry patients were studied who initiated dialysis between 1985 and 1993, similar to the European Registry. Diabetic and non-diabetic controls matched by age, gender, race, year of dialysis initiation, and initial dialysis modality were examined for comparison.

RESULTS

: During the years 1995 to 1998, the mean age of Fabry patients that initiated dialysis was 42 years, 83% were Caucasian, and 10% were African American. Despite the X-linked inheritance of Fabry disease, 12% of Fabry patients on dialysis were female. At initiation of dialysis mean serum albumin and creatinine were significantly higher and mean body mass index was significantly lower among Fabry patients, but mean glomerular filtration rate was similar to controls. Fabry patients tended to have a lower three-year survival compared to non-diabetic controls, but the results were not significantly different. In a larger cohort of Fabry patients who initiated dialysis between 1985 and 1993, the three-year survival of Fabry patients was significantly lower than non-diabetic controls: 63% (95% CI, 50 to 75%) versus 74% (95% CI, 67 to 80%; P=0.03).

CONCLUSION

: End-stage renal disease is associated with significant morbidity and mortality among patients with Fabry disease. Recent evidence that progression of Fabry disease may be attenuated by enzyme replacement therapy necessitates increased awareness of Fabry disease and its comorbidities.

New insights into the origin of the Gaucher disease-causing mutation N370S: extended haplotype analysis using the 5GC3.2, 5470 G/A, and ITG6.2 polymorphisms

Gaucher disease is a lysosomal storage disorder inherited as an autosomal recessive trait. It is highly prevalent among Ashkenazi Jews but also present in other populations. Mutations in the glucocerebrosidase gene are the main cause of the disorder. One of these gene defects, N370S, is the most prevalent disease allele in the Ashkenazi Jewish patient population and also frequent in others, such as the Spanish and Portuguese Gaucher disease populations. Previous results based on haplotype analysis support the hypothesis of a single origin for this mutation. We have extended the haplotype analysis to include three newly described polymorphisms, 5GC3.2, ITG6.2 (very close to the gene), and 5470 G/A (in intron 7 of the GBA gene) in a sample of Spanish and Ashkenazi Jewish patients. The results confirm the single origin of the mutation in these two populations. The 5470A allele is only found in N370S chromosomes and was believed to be limited to the Portuguese population. Here we describe that it is also present with a similar frequency in Spain. Moreover, most of the 5470A alleles are found within particular haplotypes, which have some differences from the common N370S haplotype.

Identification and characterization of a novel mutation c.1090G>T (G325W) and nine common mutant alleles leading to Gaucher disease in Spanish patients

BACKGROUND

Gaucher disease is an autosomal recessive disorder resulting from mutations in the glucocerebrosidase gene (GBA). The lack of full genotype/phenotype correlation complicates counseling regarding clinical outcome and treatment recommendations.

SUBJECTS AND METHODS

Several mutations in the human beta-glucosidase gene associated with Gaucher disease in 16 Spanish families were identified utilizing a combination of methods: enzymatic restriction, PCR-SSCP, and sequence analyses. Expression studies were performed following the introduction of the mutagenized human acid beta-glucosidase cDNA into COS-1 cells, and the residual enzyme activities of the mutant protein were measured and compared with the normal cDNA.

RESULTS

The identified mutations and corresponding residual enzyme activities of the expressed protein are as follows: c.517A>C (T134P), 1%; c.721G>A (G202R), 17%; c.1090G>T (G325W), 13.9%; c.1093G>A (E326K), 26%; c.1208G>A (S364N), 4.1%; c.1226A>G (N370S), 17,8%; c.1246G>A (G377S), 17.6%; c.1289C>T (P391L), 8.5%; c.1448T>C (L444P), 3%; and c.1504C>T (R463C), 24.5%.

CONCLUSIONS

Site-directed mutagenesis and expression in COS-1 cells are useful methods to increase our understanding of causality in Gaucher disease and the correlation between disease severity, gene defects, and residual enzyme activity. Our study demonstrates the functional consequences of the identified human beta-glucosidase mutations (T134P, S364N, G377S, P391L, and G325W) and provide evidence for the molecular and biochemical basis of Gaucher disease, among patients of Spanish ancestry.

Isolation and characterization of the normal canine beta-galactosidase gene and its mutation in a dog model of GM1-gangliosidosis

The acid beta-galactosidase cDNA of Portuguese Water dogs was isolated and sequenced. The entire coding region of the gene consists of 2004 nucleotides encoding a protein of 668 amino acids. Its encoding sequence indicates approximately 86.5% identity at the nucleotide level and about 81% identity at the amino acid level with the encoding region of the human acid beta-galactosidase gene. The deduced amino acid sequence contains a 24-amino-acid putative signal sequence, six possible glycosylation sites, and seven cysteine residues. A homozygous recessive mutation, causing canine GM1-gangliosidosis, was identified at nucleotide G200-->A in exon 2 resulting in an Arg60-->His (mutation R60H) amino acid substitution. The mutation creates a new restriction enzyme site for Pml1. Genotyping 115 dog samples for this acid beta-galactosidase gene alteration readily distinguished affected homozygous recessives (n=5), heterozygous carriers (n=50) and normal homozygotes (n=60). DNA mutation analysis provided a method more specific than enzyme assay of beta-galactosidase for determination of carriers.

Bone and joint complications related to Gaucher disease

There is a broad spectrum of Gaucher disease-related skeletal complications, ranging from asymptomatic osteopenia to osteonecrosis (of the shoulders and hips) with secondary degenerative joint disease. Characterization of the pattern and severity of bone involvement in the individual patient requires the application of conventional and advanced radiographic techniques. The introduction of enzyme replacement therapy (ERT) for this inborn error of glycosphingolipid metabolism has focused great interest in determining the nature and extent of the bone responses with this mode of treatment. The multifactorial etiology of the bone complications necessitates a multifaceted approach, combining pharmacologic strategies with physical therapy and orthopedic intervention. As bone disease can lead to chronic pain and debility with a resultant adverse impact on quality of life, it is important that patients be monitored closely and that early intervention with ERT prior to established bone disease (infarction and fibrosis) be considered.

Non-pseudogene-derived complex acid beta-glucosidase mutations causing mild type 1 and severe type 2 gaucher disease

Gaucher disease is an autosomal recessive inborn error of glycosphingolipid metabolism caused by the deficient activity of the lysosomal hydrolase, acid beta-glucosidase. Three phenotypically distinct subtypes result from different acid beta-glucosidase mutations encoding enzymes with absent or low activity. A severe neonatal type 2 variant who presented with collodion skin, ichthyosis, and a rapid neurodegenerative course had two novel acid beta-glucosidase alleles: a complex, maternally derived allele, E326K+L444P, and a paternally inherited nonsense mutation, E233X. Because the only other non-pseudogene-derived complex allele, D140H+E326K, also had the E326K lesion and was reported in a mild type 1 patient with a D140H+E326K/K157Q genotype, these complex alleles and their individual mutations were expressed and characterized. Because the E233X mutation expressed no activity and the K157Q allele had approximately 1% normal specific activity based on cross-reacting immunologic material (CRIM SA) in the baculovirus system, the residual activity in both patients was primarily from their complex alleles. In the type 1 patient, the D140H+E326K allele was neuroprotective, encoding an enzyme with a catalytic efficiency similar to that of the N370S enzyme. In contrast, the E326K+L444P allele did not have sufficient activity to protect against the neurologic manifestations and, in combination with the inactive E233X lesion, resulted in the severe neonatal type 2 variant. Thus, characterization of these novel genotypes with non-pseudogene-derived complex mutations provided the pathogenic basis for their diverse phenotypes.

Gaucher disease: recommendations on diagnosis, evaluation, and monitoring

BACKGROUND

Timely diagnosis and continued monitoring of patients with type I Gaucher disease is critical because skeletal involvement can permanently disable patients and visceral organ involvement can lead to abdominal pain and secondary hematologic and biochemical complications.

OBJECTIVE

To seek clinical consensus for minimum recommendations for effective diagnosis and monitoring of patients with type I Gaucher disease. PARTICIPANTS, EVIDENCE, AND CONSENSUS PROCESS: Contributing authors collaborated in quarterly meetings over a 2-year period to synthesize recommendations from peer-reviewed publications and their own medical experiences. These physicians care for most patients with Gaucher disease in the United States and serve as the US Regional Coordinators for the International Collaborative Gaucher Group Registry, the world's largest database for this disorder.

CONCLUSIONS

The definitive method of diagnosis is enzyme assay of beta-glucocerebrosidase activity. Schedules differ for monitoring complications of type I Gaucher disease, depending on symptoms and whether enzyme replacement therapy is used. Hematologic and biochemical involvement should be assessed by complete blood cell count, including platelets, acid phosphatase, and liver enzymes, at baseline and every 12 months in untreated patients and every 3 months and at enzyme replacement therapy changes in treated patients. Visceral involvement should be assessed at diagnosis using magnetic resonance imaging or computed tomographic scans. Skeletal involvement should be assessed at diagnosis using T1- and T2-weighted magnetic resonance imaging of the entire femora and plain radiography of the femora, spine, and symptomatic sites. Follow-up skeletal and visceral assessments are recommended every 12 to 24 months in untreated patients, and every 12 months and at enzyme replacement therapy changes in treated patients.

The health-related quality of life of adults with Gaucher's disease receiving enzyme replacement therapy: results from a retrospective study

Few studies have reported on the effect of Gaucher's disease on patient-reported, health-related quality of life (HRQoL) and we do not know how the HRQoL burden of Gaucher's disease compares to that of other chronic conditions, what areas of HRQoL are most affected or how the course of change in HRQoL compares with that observed for other conditions or for the general adult population. The purpose of this study was to estimate (1) the HRQoL burden associated with Gaucher's disease managed by enzyme replacement therapy (ERT), (2) recalled changes in HRQoL since ERT initiation and (3) risk factors predictive of HRQoL outcomes. We sampled 212 patients with Gaucher's disease recruited from 146 physicians prescribing ERT in the US. The patients were at least 14 years of age and had been on ERT from 1 to 51 months. The mean (SD) age of the participants was 45 (17) years. Forty-nine percent had had a prior splenectomy and 26% had had a joint replacement. We administered the SF-36 Health Survey (SF-36) and three questions about changes in physical, mental and general HRQoL since starting ERT. The patients with Gaucher's disease scored significantly worse than the age- and gender-adjusted US norms on five of the eight SF-36 subscales (p < 0.05). Age (p < 0.0001) and joint replacement (p < 0.001) were negatively associated with physical health. The presence of an intact spleen (p < 0.01) and a longer duration of ERT (p < 0.01) were associated with better mental health. When asked about changes in HRQoL since starting ERT, at least half of the patients reported fewer limitations in physical activities (53%), better general health perceptions (77%) and less negative emotions (49%) at the time of the interview. Patients who had been receiving ERT for approximately 4 years recalled four and five times more improvement in general HRQoL in comparison with recalled changes over a 4 year period among adults in the general population (p < 0.001) and a congestive heart failure population (p < 0.01), respectively. Odds ratios (ORs) revealed that female patients were more likely to report improvements in general HRQoL than males (OR = 4.50 and 95% CI = 2.19-9.25) and 45 year old patients were less likely to report improvements than 35 year olds (OR = 0.76 and 95% CI = 0.62-0.94). Relative to patients who had been receiving ERT for 1 year, those who had been receiving ERT for 2 and 4 years were 1.40 (95% CI = 1.06-1.84) and 2.75 (95% CI = 1.20-6.27) times more likely to report improvements in general HRQoL, respectively. In summary, patients with Gaucher's disease on ERT reported an improvement in HRQoL that was greater than that reported by patients with other chronic diseases. However, Gaucher's patients treated for up to 51 months scored below equivalent adults in the general population. The risk factors, including age and history of splenectomy and joint replacement, warrant further study. Standardized HRQoL measures are likely to prove useful in understanding better the outcomes from the Gaucher's patient's perspective.

Gaucher disease: assessment of skeletal involvement and therapeutic responses to enzyme replacement

The clinical, pathological and radiological manifestations of type 1 Gaucher disease and the role of imaging techniques such as CT, MRI and sulfur-colloid scintigraphy in the management of these patients is discussed. MRI appears to be the most valuable imaging technique for evaluating bone marrow involvement and detecting disease activity. MRI is also useful in assessing therapeutic responses to enzyme replacement therapy.

Gaucher's Disease. Pathological features

Gaucher's disease is the most common lysosomal storage disease. The pathological features are a consequence of the progressive accumulation of glucosylceramide within mononuclear phagocytes. A wide variety of gross and microscopic anatomical changes are seen, primarily in the bone marrow, liver, spleen and bones. It is probable that cellular reactions to the presence of Gaucher cells ('lipid-engorged' macrophages) contribute to the tissue damage observed in this disease, although only a few investigations have been undertaken to elucidate what, if any, other mechanisms may play a contributory role in defining individual disease outcome. The general clinico-pathological features of Gaucher's disease are reviewed herein, with exclusion of the central nervous system and skin involvement, which are covered elsewhere.

Scintigraphic monitoring of reticuloendothelial system in patients with type 1 Gaucher disease on enzyme replacement therapy

The purpose of this study was to define the scintigraphic pattern of marrow replacement and changes in reticuloendothelial activity after enzyme replacement therapy in patients with Gaucher disease.

METHODS

Forty patients underwent baseline whole-body imaging with 99mTc-sulfur colloid and evaluation of liver and spleen volume with CT or magnetic resonance imaging. Thirty-seven of the 40 patients were treated with enzyme replacement. Therapeutic responses of central and peripheral bone marrow and the changes in pulmonary uptake of 99mTc-sulfur colloid were assessed visually at 1-4 yr after the start of therapy. Changes in liver and spleen volumes were analyzed quantitatively. The initial pattern of marrow involvement was correlated with disease severity (based on baseline blood counts and liver and spleen volumes).

RESULTS

Baseline studies revealed that 38 of 40 (95%) and 28 of 40 (70%) of the patients in this study had abnormal peripheral and central marrow activity, respectively. Twenty of 24 evaluable patients (83.3%) on therapy showed regression of peripheral bone marrow activity to a more proximal location in the lower extremities, increased ratio of pelvic/proximal femoral activity to distal activity or both. Fourteen of 19 treated patients (73.7%) with abnormal initial central marrow activity showed detectable improvement in central bone marrow activity as a result of therapy. In patients with initial lung uptake of 99mTc-sulfur colloid, 91% showed complete resolution of the uptake after therapy. These changes in colloid uptake and distribution were associated with significant reductions in liver and spleen volumes and improvements in blood counts.

CONCLUSION

Most patients with Gaucher disease demonstrate increased central bone marrow activity and regression of activity in peripheral bone marrow with enzyme replacement therapy. Additionally, the abnormal phagocytic pulmonary activity observed before therapy in many of the patients resolves.

Identification and expression of acid beta-glucosidase mutations causing severe type 1 and neurologic type 2 Gaucher disease in non-Jewish patients

Gaucher disease, the most prevalent lysosomal storage disease, occurs in three subtypes, all resulting from mutations in the acid beta-glucosidase gene. Molecular studies in five severely affected type 1 and two type 2 Gaucher disease patients of non-Jewish descent identified six new mutations: K74X, W179X, G195E, S271N, V352L, and a two-base deletion in exon 10 (1450del2). Two additional mutations identified in these patients (R48W and G202R) have been reported previously, but were not expressed or characterized. Heterologous expression in Sf 9 cells using the baculovirus system revealed that the missense mutations, R48W and V352L, had 14 and 7%, respectively, of the specific activity based on cross-reacting immunologic material expressed by the normal allele. In contrast, the G195E, G202R, and S271N mutant alleles were more severely compromised with only 1-2% of the normal expressed specific activity based on cross-reacting immunologic material. Structural distortion at the active site was probed by comparing the interaction of the mutant enzymes with active site-directed inhibitors (castanospermine, conduritol B epoxide and deoxynojirimycin). R48W, G202R, and S271N were normally inhibited, whereas the V352L and G195E mutant enzymes had significantly decreased binding affinity. These mutations further expand the genetic heterogeneity in the lesions causing Gaucher disease types 1 and 2, and further delineate genotype/phenotype correlations and functional domains within the acid beta-glucosidase gene.

Bone density in Type 1 Gaucher disease

Skeletal involvement is a major source of complications in patients with Type 1 Gaucher disease. To investigate the bone density and potential usefulness of bone densitometry in Gaucher disease, dual-energy X-ray absorptiometry was used to measure the density of the lumbar spine, femoral neck, trochanter, and distal radius in 61 adult patients ranging in age from 22 to 77 years. The mean bone density at each site was significantly lower than expected for age and sex. The severity of the osteopenia correlated significantly with other clinical indicators of disease severity, including the N370S/84GG genotype, prior splenectomy, and hepatomegaly. The bone density measurements also correlated significantly with the severity of skeletal disease as assessed by skeletal radiography. Vertebral density remained an independent predictor of the severity of bone involvement even after controlling for age, sex, weight, genotype, splenectomy, and hepatomegaly. These findings suggest that bone density measurements provide a quantitative assessment of bone involvement in Type 1 Gaucher disease, which may permit serial, noninvasive monitoring of bone changes in this progressive disorder.

Use of various diagnostic methods in a patient with Gaucher disease type I

A series of plain radiographs, bone scans, bone marrow scans, and MRIs is reported in a patient with Gaucher disease type I, in whom two episodes of acute bone crisis developed during a 6-year period of follow-up. Acute bone crisis and global indolent bone marrow displacement could both be assessed by bone marrow scintigraphy, whereas MRI could better clarify the corti-comedullary alteration after bone infarction. Thus, MRI and bone marrow scintigraphy could be used as complementary imaging methods in the management of patients with Gaucher disease.

Regression of skeletal changes in type 1 Gaucher disease with enzyme replacement therapy

A 9-year-old patient presented with an acute onset of pain of the right femur showing destructive changes with periosteal elevation mimicking osteomyelitis. Technetium-99m sulfur colloid (99mTc SC) marrow scan revealed lack of uptake in the right femoral head and the entire shaft of the right femur. Eight months following enzyme replacement therapy, radiography showed almost complete reconstitution of the femoral shaft, and 99mTc SC marrow scan uptake returned to normal.

Antisulfatide antibody and neuropathy in a patient with Gaucher's disease

We report the presence of antisulfatide antibodies in a patient with type I Gaucher's disease and peripheral neuropathy. The association of Gaucher's disease with hypergammaglobulinemia and monoclonal gammopathy is well documented whereas its association with peripheral neuropathy is rare. We discuss whether antibodies directed against the sulfatide antigen are related to Gaucher's disease or are a coincidental association.