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D P Germain

Publications and source records attributed to D P Germain.

At least 19 recordsLinked to original sources
PubMed2006

Liquid chromatography on porous graphitic carbon with atmospheric pressure photoionization mass spectrometry and tandem mass spectrometry for the analysis of glycosphingolipids.

The study of several structural variations (the length, the degree of unsaturation and hydroxylation of the alkyl chains, the number and nature of osidic residues) helped understand the behaviour of neutral glycosphingolipids (GSLs) on porous graphitic carbon stationary phase (PGC). Atmospheric pressure photoionization mass spectrometry (APPI) and tandem mass spectrometry were used to perform the detection and the identification of molecular species in positive mode where [M+H](+) and [M-H(2)O+H](+) ions provided structural information on the fatty acid and the sphingoid base. The retention of GSLs increased with the hydrocarboneous volume of their alkyl chains and with the number of osidic residues in agreement with hydrophobic properties and polar retention effect of graphite, respectively. The presence of polar groups, such as OH-group or double bond within alkyl chains, decreased their retention. The coupling of chromatography on PGC with APPI tandem mass spectrometry detection appeared a powerful technique to discriminate isobaric molecules. Isobaric solutes differing by the position of two double bonds or by the repartition of hydrocarboneous skeleton were discriminated according to their chromatographic comportment or their mass spectrum, respectively. Among isobaric molecules, only few structures differing by the nature of osidic residue were not discriminated (i.e. glucosylceramide and galactosylceramide with similar ceramide skeleton were co-eluted and no difference in mass spectra was observed).

Atmospheric Pressure↗
PubMed2006

[The cochlea in Fabry disease: a sensorineural hearing loss model of vascular origin?].

PURPOSE: Fabry disease is an inborn error of metabolism due to a deficient activity of the lysosomal enzyme alpha-galactosidase A. The enzyme defect leads to the systemic accumulation of neutral glycosphingolipids in tissues, mainly in the vascular endothelium. STRONG POINT: The aim of this paper is to present a review of the auditory manifestations in Fabry disease, and to discuss hypothesis on the vascular origin of deafness. PERSPECTIVES: Sensorineural hearing loss in Fabry disease could be the first documented vascular pathology of the inner ear.

Cochlea↗
PubMed2006

[Neurological aspects of Fabry's disease].

Fabry disease is a rare X-linked disorder caused by deficient activity of the lysosomal enzyme alpha-galactosidase A. Progressive accumulation in lysosomes of the undegraded glycosphingolipids leads to a multi-system disease with dermatological, ocular, renal, cardiac, and neurological manifestations. Peripheral nerve involvement, neuropathic pain and chronic acroparesthesiae, are frequent and early-onset signs revealing the disease. They are due to the involvement of small nerve fiber, thus explaining the normality of electroneuromyography. Cochleo-vestibular and autonomic nervous system involvement is frequent. Besides rare aseptic meningitis, central nervous system involvement is essentially represented by cerebrovascular events (stroke, transient ischemic attack). Affecting essentially the posterior circulation, their etiologies have to be clarified: progressive stenosis of small vessels with globotriasocylceramide deposits, arterial remodeling, endothelial dysfunction, pro-thrombotic state, cerebral hypoperfusion consecutive to dysautonaumy, cardiac embolism. MRI shows numerous silent lesions, increasing with age, mainly in small perforant arteries (periventricular white matter, brainstem, cerebellum, basal ganglia). Pulvinar calcifications, due to an increase in cerebral hyperperfusion, could be specific of Fabry disease. Positon tomography analysis shows a reduced cerebral flow velocity and impaired cerebral autoregulation, secondary to the glycosphingolipid storage in vascular endothelial cells. Enzyme replacement therapy has to be carefully monitored.

Brain↗
PubMed2006

Phenotype variations in Gaucher disease.

The Gaucher phenotype is very complex and it cannot be simply evaluated on the basis of blood counts or splenomegaly, but by the analysis of all disease compartments. To establish the diagnosis of Gaucher disease, biochemical assay of glucocerebrosidase activity is the most reliable method. However, it can be supplemented by molecular diagnosis, which may be helpful to predict the severity and the rate of progression of clinical manifestations. The genotype-phenotype correlations are very complex with a high inter-individual variability in the severity of clinical manifestations within a same genotype. Genetic modifiers may play an important role in determining the eventual Gaucher phenotype. Despite of some devastating complications, which can arise with advancing age, Gaucher disease worsen progressively in the majority of patients homozygous for the N370S mutation. The analysis of the data of the International Collaborative Gaucher Group registry should provide a better understanding of the natural history of the Gaucher disease.

Adult↗
PubMed2006

Therapeutic goals in Gaucher disease.

Evidence-based therapeutic goals have been developed by several European and American experts in Gaucher disease in order to attempt to reverse the entire Type 1 Gaucher phenotype, prevent complications, improve quality of life and prevent life-threatening complications. Patients with Gaucher disease will benefit by maximum enzyme replacement treatment (ERT) efficiency if it is given at the optimal time i.e. generally during the asymptomatic phase of the disease. Currently, Cerezyme is the standard of care for all severities of type 1 Gaucher disease due to its high efficiency at ameliorating bleeding tendencies, reversing organomegaly and part of skeletal damages and eliminating bone crises. ERT has also demonstrated a remarkable safety profile with tolerability at 3 years greater than 99%. Treatment of Gaucher disease is a long-life treatment that the patient should not interrupt without a careful monitoring of the disease evolution.

1-Deoxynojirimycin↗
PubMed2004

Optimisation of the separation of four major neutral glycosphingolipids: application to a rapid and simple detection of urinary globotriaosylceramide in Fabry disease.

A simple method for the separation of the four major neutral glycosphingolipids, present in all human tissue, was developed. This gradient normal phase-HPLC method utilises a polyvinyl alcohol bonded stationary phase and an evaporative light-scattering detection (ELSD). Screening pure solvents in a binary gradient elution mode allowed, in a first step, to assess the behaviour of the studied solutes and to select the solvents for further mobile phase optimisation. The proportion of the remaining solvents was defined to reach a maximal resolution. The reduction of the analysis time and the enhancement of the signal were obtained by optimising the gradient slope and the flow-rate. Optimal levels of triethylamine and formic acid (TEA-FA) for the enhancement of the evaporative light scattering detector response were established at 0.1% (v/v). Thus, the optimal conditions for the separation of the four glycosphingolipids was obtained with a gradient elution from a 100% chloroform to a 100% acetone:methanol (90:10 (v/v)) mobile phase at 0.2 ml min-1, using a 10% min-1 gradient slope. Finally, this method was applied to detect the excess of one of the neutral sphingolipids, namely globotriaosylceramide (Gb3) in the urine of patients affected with Fabry disease. A liquid-liquid extraction of the sediments obtained from an aliquot of only ten ml of urine proved sufficient to detect the excess of Gb3 present in both hemizygote and heterozygote patients. In all, the ability of our method to detect abnormal amounts of Gb3 in urinary sediments could allow the diagnosis of weakly symptomatic Fabry patients in large screening programs

Chromatography, High Pressure Liquid↗
PubMed2004

[Gaucher disease: clinical, genetic and therapeutic aspects].

Gaucher disease (GD) is one of the most prevalent lysosomal storage disorders and one of the rare genetic diseases for which therapy is now available. Partial deficiency of glucocerebrosidase is associated with parenchymal disease of the liver, spleen, and bone marrow with concomitant anaemia and thrombocytopenia in non-neuronopathic, type 1, Gaucher disease. Severe deficiency of glucocerebrosidase caused by disabling mutation is additionally associated with neurological manifestations in the less common type 2 and type 3 Gaucher diseases. Outside of the Ashkenazi Jewish community, a high molecular diversity is observed. Clarification of genotype-phenotype relationship and the identification of modifier loci that impact on Gaucher disease phenotypes remain a critical area for research. Recombinant glucocerebrosidase (imiglucerase) is an effective mean of treating type 1 Gaucher disease and should be initiated early on in life. Amelioration of hepatosplenomegaly and of haematological manifestations is usually apparent within six months. Bone disease responds more slowly. Imiglucerase has recently been approved for the treatment of type 3 Gaucher disease. Enzyme replacement therapy cannot reverse the neurological deficits in type 2 or type 3 Gaucher disease. This should prompt further research on substrate deprivation and gene therapy.

Gaucher Disease↗
PubMed2004

Gaucher's disease: a paradigm for interventional genetics.

Gaucher's disease (GD) is one of the most prevalent lysosomal storage disorders (LSDs) and a rare genetic disease for which specific therapy is now available. GD is an autosomal, recessive, inborn error of glycosphingolipid metabolism, due to a deficiency in the enzyme acid beta-glucosidase. Partial deficiency of acid beta-glucosidase is associated with parenchymal disease of the liver, spleen, and bone marrow with concomitant anemia and thrombocytopenia in non-neuronopathic, type 1 GD. Severe deficiency of glucocerebrosidase caused by severe mutations is additionally associated with neurological manifestations in the less common type 2 and type 3 GD subtypes. Outside of the Ashkenazi Jewish community, a high molecular diversity is observed. Clarification of genotype/phenotype relationship and the identification of modifier loci that impact on GD phenotypes remains a critical area for research. Enzyme replacement therapy (ERT) is proven to be safe and effective in the treatment of type 1 GD, establishing imiglucerase as the current standard of care. Amelioration of hepatosplenomegaly and of hematological manifestations is usually apparent within 6-12 months, whereas the bone disease responds more slowly. ERT cannot reverse the neurological deficits in type 2 or type 3 GD. Small molecule inhibitors of glucosylceramide synthase are being developed for substrate reduction therapy. Other potential therapeutic options such as chaperon-mediated enzyme enhancement therapy and gene therapy are being explored.

Gaucher Disease↗
PubMed2003

Fabry disease: a functional and anatomical study of cardiac manifestations in 20 hemizygous male patients.

Fabry disease (FD, OMIM 301500) is an X-linked disorder of glycosphingolipid metabolism resulting from the deficient activity of alpha-galactosidase A, a lysosomal acid hydrolase, leading to progressive lysosomal accumulation of incompletely metabolized neutral glycosphingolipids. Cardiac involvement is frequent. The objective of this study was to characterize the cardiac abnormalities in male patients affected with classic Fabry disease and define the context in which the clinicians were able to make the diagnosis. Clinical evaluation, laboratory tests, electrocardiography (ECG) and echocardiography were performed in 20 hemizygous men (mean age 39 years, range 12-65 years). The context of diagnosis was obtained by review of patients' charts. Left ventricular hypertrophy (LVH) and/or concentric remodeling were found in 12 patients (60%). Structural changes in mitral and aortic valves were found in 25% and 10% of cases, respectively. The sensitivity of the ECG Romhilt-Estes score for LVH was high (80%). Short PR interval (40%), ST segment abnormalities and conduction delay were frequent on ECG. Left ventricular mass index, ECG scores for LVH and systolic pulmonary pressure correlated positively with age. There was no relation between classic vascular risk factors and coronary artery disease, transient ischemic attack (TIA) or stroke. Diagnosis of Fabry disease was frequently suggested by nephrologists, dermatologists or geneticists. Echocardiograph and ECG abnormalities are frequently observed in patients with Fabry disease. Cardiologists should be aware of the diagnosis of Fabry disease in patients presenting with LVH, concentric remodeling, mitral and aortic valve thickening on echocardiography, short PR interval and conduction defects on ECG.

Adolescent↗
PubMed2002

Endothelial markers and homocysteine in patients with classic Fabry disease.

AIM: Fabry disease is an X-linked inborn error of glycosphingolipid metabolism due to the deficient activity of alpha-galactosidase A, a lysosomal enzyme. It is a multisystem disorder characterized by progressive renal insufficiency, with added morbidity from cardio- and cerebrovascular involvement. The recent availability of genetically engineered enzyme offers an effective targeted treatment approach, but also emphasizes the need for surrogate markers to delineate organ damage and monitor the efficacy of enzyme replacement therapy (ERT). METHODS: Multiple endothelial factors and plasma homocysteine concentrations were investigated in 12 consecutive hemizygous males with classic Fabry disease and 15 controls as part of an exhaustive baseline evaluation prior to ERT. RESULTS: Compared with the controls, plasma concentrations of homocysteine were significantly (p < 0.01) higher in patients with Fabry disease in the absence of chronic renal failure or vitamin deficiency. Plasma concentrations of vascular cell adhesion molecule-1 were also significantly (p < 0.05) higher in the patients, and there was a trend for decreased endothelin-1 levels. No difference was found in serum intercellular adhesion molecule-1, plasma P-selectin, serum E-selectin and plasma thrombomodulin between the patients and controls. CONCLUSIONS: The results do not reveal measurable evidence for endothelial and leukocyte activation that could reliably serve as surrogate markers for routine monitoring of the efficacy of ERT in patients with Fabry disease. While the exact origin and clinical significance of hyperhomocysteinaemia in Fabry disease remains to be studied in a larger cohort of patients carefully monitored for their concurrent medications, especially carbamazepine, we suggest that patients may benefit from folic acid or multivitamin therapy to treat this additional vascular risk factor, when present.

Adolescent↗
PubMed2002

Arterial remodelling in Fabry disease.

AIM: The enzymatic defect in Fabry disease results in the slow systemic deposition of uncleaved glycosphingolipids in the lysosomes of vascular endothelium and smooth muscle cells, leading to ischaemic strokes, cardiomyopathy and renal failure. Whereas it is known that Fabry disease affects small blood vessels, little is known about its effects on peripheral large arteries. We therefore set out to compare parameters of arterial wall structure and function in a cohort of patients with Fabry disease and an age-matched control group. METHODS: Large artery phenotype was non-invasively investigated in 21 hemizygous patients with Fabry disease and 24 age-matched male controls. Common carotid and radial artery diameter, intima-media thickness (IMT) and distensibility were determined with high-definition echotracking systems and aplanation tonometry. RESULTS: Patients with Fabry disease had a significant twofold increase in radial artery IMT and distensibility, independent of body surface area, age and mean blood pressure. In both groups, older age at the time of examination was significantly associated with larger radial artery IMT. The relationship between age and radial IMT was 2.3-fold higher in patients with Fabry disease than in controls (p < 0.01). Carotid IMT was mildly but significantly increased in patients with Fabry disease (+18%), whereas distensibility was unchanged. CONCLUSION: This study presents evidence of a major increase in arterial wall thickness and distensibility, measurable at the site of a medium-sized artery, in a cohort of patients with classic Fabry disease.

Adolescent↗
PubMed2001

Mutation analysis of the acid beta-glucosidase gene in a patient with type 3 Gaucher disease and neutralizing antibody to alglucerase.

The beneficial effects of macrophage-targeted glucocerebrosidase (alglucerase, Ceredase) in patients with Gaucher disease are well established. A minority of recipients develop transient non-neutralizing antibodies to the exogenous enzyme. A 7-year-old patient with type 3 Gaucher disease, whose clinical course began to deteriorate while receiving alglucerase developed a progressively increasing titer of IgG antibody, that blocked the catalytic activity of alglucerase. We investigated the acid beta-glucosidase genotype in this patient. Direct sequencing of both cDNA and genomic PCR products was used to characterize the mutations underlying acid beta-glucosidase deficiency. The patient was shown to be a compound heterozygote for a previously reported missense mutation (G377S), and a novel single nucleotide deletion (g5255delT). The transcript originating from the latter allele was undetectable in RT-PCR experiments. We report the first characterization of a GBA genotype associated with the development of neutralizing antibody to alglucerase, in a patient affected with type 3 Gaucher disease. Our results may help to shed light on the mechanisms underlying this phenomenon which, in the rare instances where it occurs, hampers the efficacy of enzyme replacement therapy.

Antibody Formation↗
PubMed2001

Safety and efficacy of recombinant human alpha-galactosidase A replacement therapy in Fabry's disease.

BACKGROUND: Fabry's disease, lysosomal alpha-galactosidase A deficiency, results from the progressive accumulation of globotriaosylceramide and related glycosphingolipids. Affected patients have microvascular disease of the kidneys, heart, and brain. METHODS: We evaluated the safety and effectiveness of recombinant alpha-galactosidase A in a multicenter, randomized, placebo-controlled, double-blind study of 58 patients who were treated every 2 weeks for 20 weeks. Thereafter, all patients received recombinant alpha-galactosidase A in an open-label extension study. The primary efficacy end point was the percentage of patients in whom renal microvascular endothelial deposits of globotriaosylceramide were cleared (reduced to normal or near-normal levels). We also evaluated the histologic clearance of microvascular endothelial deposits of globotriaosylceramide in the endomyocardium and skin, as well as changes in the level of pain and the quality of life. RESULTS: In the double-blind study, 20 of the 29 patients in the recombinant alpha-galactosidase A group (69 percent) had no microvascular endothelial deposits of globotriaosylceramide after 20 weeks, as compared with none of the 29 patients in the placebo group (P<0.001). Patients in the recombinant alpha-galactosidase A group also had decreased microvascular endothelial deposits of globotriaosylceramide in the skin (P<0.001) and heart (P<0.001). Plasma levels of globotriaosylceramide were directly correlated with clearance of the microvascular deposits. After six months of open-label therapy, all patients in the former placebo group and 98 percent of patients in the former recombinant alpha-galactosidase A group who had biopsies had clearance of microvascular endothelial deposits of globotriaosylceramide. The incidence of most treatment-related adverse events was similar in the two groups, with the exception of mild-to-moderate infusion reactions (i.e., rigors and fever), which were more common in the recombinant alpha-galactosidase A group. IgG seroconversion occurred in 88 percent of patients who received recombinant alpha-galactosidase A. CONCLUSIONS: Recombinant alpha-galactosidase A replacement therapy cleared microvascular endothelial deposits of globotriaosylceramide from the kidneys, heart, and skin in patients with Fabry's disease, reversing the pathogenesis of the chief clinical manifestations of this disease.

Adolescent↗
PubMed2001

Identification of novel polymorphisms in the pM5 and MRP1 (ABCC1) genes at locus 16p13.1 and exclusion of both genes as responsible for pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is an inherited systemic disorder of connective tissue, characterized by progressive calcification of the elastic fibers in the eye, the skin, and the cardiovascular system. The PXE locus has been mapped to chromosome 16p13.1, and was recently further refined to a 500 kb-region, containing four candidate genes : MRP1 (ABCC1), MRP6 (ABCC6), pM5, and two copies of an unknown gene, the later we subsequently found to be identical to the gene encoding the Nuclear Pore Interacting Protein (NPIP). In a comprehensive mutational screening, we have analysed the entire coding region of the pM5, MRP1, and NPIP genes in 7 patients affected with pseudoxanthoma elasticum, but failed to find evidence of disease-causing defects in any of these three genes. Five synonymous (G232G, P395P, A862A, G912G, D1106D), and five non synonymous (V404I, N458K, D490N, F1141I, G1195R) polymorphisms were found in the pM5 gene, for which we also corrected errors in the published cDNA sequence. Analysis of the MRP1 transcript lead to the discovery of two polymorphisms (T117M, S1512L). No variant was evidenced during our screening of the NPIP gene. Our data exclude the responsibility of the pM5, MRP1 and NPIP genes in PXE, and strongly suggest that mutations in the last remaining candidate gene, MRP6, which encodes a 1503 amino-acid ABC membrane transporter, are the genetic defect responsible for PXE.

ATP-Binding Cassette Transporters↗
PubMed2001

Co-occurrence and contribution of Fabry disease and Klippel-Trénaunay-Weber syndrome to a patient with atypical skin lesions.

Fabry disease (FD) is an X-linked recessive inborn error of glycosphingolipid metabolism. Among clinical symptoms, maculopapular skin lesions, known as angiokeratoma, most often appear on the lower abdomen, scrotum, and thighs, with a tendency toward bilateral symmetry. A 30-year-old male patient was referred to us for evaluation of a complex vascular and cutaneous malformation. Skin examination showed numerous angiokeratoma, which had developed only on the right part of the body, with a sharp delineation in the midline of the trunk. The diagnosis of FD was confirmed by demonstration of a decreased alpha-galactosidase A activity, and the patient was shown to be hemizygote for a missense mutation (R342Q) in the alpha-galactosidase A gene (GLA). This mutation was also demonstrated in DNA extracted from fibroblast cultures established from both affected and unaffected skin areas, thus excluding the hypothesis of somatic mosaicism or revertant mosaicism. Interestingly, the diagnosis of Klippel-Trénaunay-Weber syndrome (KTWS) was also made, through clinical and radiological investigations. This is the first report on the association between FD and KTWS. Karyotype analysis was normal. It is likely that the mixed vascular malformations of KTWS affecting capillary and venous systems have contributed to the unusual angiokeratoma distribution pattern observed in the patient.

Adult↗