[Contribution of the measurement of globotriaosylceramide in urine to the diagnosis and follow-up of Fabry disease]. / Intérêt du dosage du globotriaosylcéramide urinaire pour le diagnostic et le suivi du traitement de la maladie de Fabry.

Globotriaosylceramide (Gb(3)) has been measured in urine of 35 male hemizygotes and 66 female heterozygotes for Fabry disease (FD). In males, Gb(3) measurement allows to confirm the diagnosis which is based on deficient α-galactosidase A (α-Gal A) activity in leukocytes. Our results show that hemizygotes for classic FD have increased Gb(3) and C24/C18 isoforms ratio. Hemizygotes for FD variants have slightly elevated or normal Gb(3) and/or C24/C18 ratio. These variants often have a residual α-Gal A activity, and milder clinical signs. In females, urinary Gb(3) is more informative than α-Gal A activity in leukocytes. Our study shows that urinary Gb(3) (measurement and C24/C18 ratio) allows the diagnosis of 92 % of classical FD heterozygotes, and is often normal in variant FD heterozygotes. The diagnosis of FD heterozygote cannot be completely excluded even if urinary Gb(3) and α-Gal A in leukocytes are normal. Urinary Gb(3) can be used for therapeutic follow-up (enzyme replacement therapy) when increased.

[Contribution of genotyping in Fabry's disease]. / Apports du génotypage dans la maladie de Fabry.

Fabry's disease is an X-linked disorder due to mutations in the GLA gene encoding the lysosomal enzyme alpha-galactosidase A. Clinically, most patients present with the "classical" form, though "variant" forms with inaugural or preminent heart or kidney involvement have been described. Heterozygous women are most often symptomatic though generally less severely affected than men. We performed mutation analysis in 170 patients from 65 families and identified 55 different mutations. Our results confirm the wide molecular heterogeneity at this locus. Molecular study allows to confirm the diagnosis in male patients and the reliable diagnosis of heterozygous females in the family as biochemical tests (alpha-galactosidase A activity and urinary Gb(3) study) can be normal. However, in a few cases in which the index case is a female, it may remain difficult in the absence of an extensive familial study, to confirm (identification of a new missense the pathogenicity of which is unknown) or rule out (no gene alteration found) an heterozygote. Generally, genotype/phenotype correlations remain difficult as only a few mutations are more frequent. Furthermore, variations of the phenotype, even within the same family, suggest that other factors (genetic and epigenetic) could influence disease progression.

Phenotypic spectrum of fucosidosis in Tunisia.

Fucosidosis (OMIM 230000) is a rare autosomal recessive lysosomal disorder due to deficient α-L-fucosidase activity(EC 3.2.1.51), leading to the accumulation of fucose-containing glycolipids and glycoproteins in various tissues. This study contained the largest ever Tunisian survey of fucosidosis patients, diagnosed during the period 1987-2007. The clinical pictures and outcomes of these patients are compared with literature data. Ten patients (8 boys and 2 girls) from six unrelated families were diagnosed at a mean age of 29 ± 10.3 months. Six of the patients were diagnosed as having the more severe phenotype. The other four cases presented the low progressive phenotype. This distinction was determined by the presence or absence of angiokeratoma and age of death. For all of the patients in our survey, early motor development was more severely delayed than described in the literature. Six patients presented psychomotor decline during the second year of life. Clinical features consist of variable mental retardation (all patients), progressive spastic quadriplegia (6/10 cases), coarse facies (9/10 cases), growth retardation (7/9 cases), visceromegaly (3 cases), angiokeratoma corporis diffusum (4 cases), recurrent bronchopneumonias (all cases), seizures (4 cases) and variable degrees of dysostosis multiplex (all cases). Portal cavernoma, never described in the literature, was observed in one patient. The outcomes were severe in this survey, probably owing to restricted health care; death occurred in 6 of the 10 patients before age 10 years, following recurrent pulmonary infections and neurological deterioration. No intrafamilial variability was noted in the multiplex families. The clinical presentation and outcomes of some of these patients were consistent with the continuous clinical spectrum of severity in fucosidosis attested by most clinical studies.

Dilative arteriopathy and basilar artery dolichoectasia complicating late-onset Pompe disease.

BACKGROUND: Strokes related to intracranial aneurysm or arteriopathy have been reported in a few patients with late-onset Pompe disease. These reports suggested that cerebral vessel involvement could be an underrecognized complication of this disease. METHODS: We report cerebral artery involvement in three French patients with late-onset Pompe disease. RESULTS: The first patient died at age 35 years from complications of a giant fusiform aneurysm of the basilar artery, and her 34-year-old sister showed evidence of dolichoectatic basilar artery on magnetic resonance angiography. A dilative arteriopathy complicated with carotid artery dissection was diagnosed in the third patient, aged 50 years. Two patients are currently being treated with enzyme replacement therapy (alglucosidase alfa), and regular angiographic follow-up showed the absence of progression of vascular abnormalities in one of them. CONCLUSION: These observations, combined with previously reported cases, confirm that Pompe disease should be recognized as a predisposing condition to dilative arteriopathy and cerebral aneurysm formation, although the real incidence of these vascular complications remains unknown.

[Molecular analysis of the p.Asn 370 Ser mutation in Gaucher disease]. / Analyse moléculaire de la mutation p.Asn 370 Ser dans la maladie de Gaucher.

Gaucher disease is one of the most prevalent lysosomal disorders. In this present study, we report a diagnostic strategy of type 1 Gaucher disease. The application of combined methods in molecular biology allowed us to analyse the p.Asn 370 Ser mutation. The affected individual activity is very low. First, we have to used the enzymatic digestion method. Then, we have to identified the mutation by the refractory mutation system technique using specific primers for the p.Asn 370 Ser mutation. These analyses are supplemented by the direct sequencing in order to seek and confirm this mutation. Finally, the absence of the 55 pb deletion in exon 9 among corroborated the presence of the homozygous genotype of this p.Asn 370 Ser in the patient DNA.

Methods for a prompt and reliable laboratory diagnosis of Pompe disease: report from an international consensus meeting.

Pompe disease is an autosomal recessive disorder of glycogen metabolism caused by a deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA). It presents at any age, with variable rates of progression ranging from a rapidly progressive course, often fatal by one-year of age, to a more slowly, but nevertheless relentlessly progressive course, resulting in significant morbidity and premature mortality. In infants, early initiation of enzyme replacement therapy is needed to gain the maximum therapeutic benefit, underscoring the need for early diagnosis. Several new methods for measuring GAA activity have been developed. The Pompe Disease Diagnostic Working Group met to review data generated using the new methods, and to establish a consensus regarding the application of the methods for the laboratory diagnosis of Pompe disease. Skin fibroblasts and muscle biopsy have traditionally been the samples of choice for measuring GAA activity. However, new methods using blood samples are rapidly becoming adopted because of their speed and convenience. Measuring GAA activity in blood samples should be performed under acidic conditions (pH 3.8-4.0), using up to 2 mM of the synthetic substrate 4-methylumbelliferyl-alpha-D-glucoside or glycogen (50 mg/mL), in the presence of acarbose (3-9 microM) to inhibit the isoenzyme maltase-glucoamylase. The activity of a reference enzyme should also be measured to confirm the quality of the sample. A second test should be done to support the diagnosis of Pompe disease until a program for external quality assurance and proficiency testing of the enzymatic diagnosis in blood is established.

[Hurler syndrome. Early diagnosis and successful enzyme replacement therapy: a new therapeutic approach. Case report]. / Mucopolysaccharidose de type I: intérêt d'un diagnostic et d'une enzymothérapie substitutive précoces. A propos d'un cas.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder due to alpha-L-iduronidase deficiency. Its severe prognosis has been significantly improved by enzyme replacement therapy using recombinant human alpha-L-iduronidase (laronidase). We report the case of a boy who was diagnosed at 19 months of age with Hurler's disease, the most severe form of MPS I, and received thereafter a treatment by laronidase, resulting in clinical and biological improvement. The aim of this case report is to draw physicians' attention on the presenting signs of Hurler's disease, in order to enable an earlier diagnosis, increasing the treatment's benefits.

[Biochemical and molecular diagnosis of Gaucher disease in Tunisia]. / Diagnostic biochimique et moléculaire de la maladie de Gaucher en Tunisie.

Our study was carried out at a family from the Sahel (Tunisia). The father (index case) and his two children (son and daughter). The father beta-glucocerebrosidase (GCB) activity showing a deficit. These biochemical analyses are supplemented by molecular studies: enzymatic digestion and the direct sequencing. Two mutations were analysed, the p.Asn 370 Ser and the p.Leu 444 Pro. The DNA sequencing confirmed the presence of the homozygous genotype of this p.Asn 370 Ser in the father DNA and the heterozygous one in the two children DNA. It has no detection of the 55 pb deletion in exon 9 among all the specimens of DNA treated. The mutation p.Asn 370 Ser is associated with Gaucher disease type 1 correlated of a total absence of neurological involvements.

[Late diagnosis of a McArdle disease's case (type V glycogenosis)]. / Diagnostic tardif d'une maladie de McArdle (glycogénose de type V).

McArdle's disease is a metabolic myopathy characterized by a myophosphorylase deficiency resulting in an inability to degrade glycogen stores. We report the case of a 48 years old patient who complained since adolescence of rest and exercise myalgias and presented a chronic increased plasma creatine kinase activity. First, a maximal exercise test was performed. This test demonstrated a quasi lack of rise of respiratory exchange ratio and of blood lactate, possibly due to a glycogenolytic/glycolytic pathway deficiency. Second, a biopsy of vastus lateralis muscle was performed using Bergström needle. As expected, the analysis of mitochondrial function was normal. The in vitro screening test of the glycogenolysis/glycolysis pathway showed a lack of lactate production in presence of glycogen substrate. The study of muscular metabolism of glycogen revealed a glycogen accumulation and a decrease of active and total phosphorylase activities. These data allowed us to diagnose a type V glycogenosis, or McArdle's disease. The patient appeared heterozygous for the most frequent mutation (p.R50X).

[Mucopolysaccharidosis type I: identification of alpha-L-iduronidase mutations in Tunisian families]. / La mucopolysaccharidose de type I: identification des mutations du gène alpha-L-iduronidase dans des familles tunisiennes.

UNLABELLED: Mucopolysaccharidosis type I (MPS I) is a lysosomal disease due to mutations in the gene encoding alpha-l-iduronidase (IDUA) leading to variable clinical phenotypes with progressive severe organomegaly, bone and neurological involvement in the most severe forms. The aim of our study was to propose in Tunisia a strategy of molecular and prenatal diagnosis of the MPS I. POPULATION AND METHODS: Our study was carried out on 8 MPS I patients recruited from different Tunisian regions and issued from 5 unrelated families. All the patients were offspring of consanguineous marriages. RESULTS: The clinical and biological study led to diagnose 5 Hurler patients and 3 Hurler-Scheie patients. Three IDUA mutations were identified by molecular analysis within 6 different families: a novel mutation p.F602X and 2 already described mutations p.P533R and p.R628X. DISCUSSION: MPS I is a heterogeneous disease characterized by variability of the phenotypes. The missense mutation p.P533R associated with the intermediate phenotype was the most frequent in the Tunisian but also in the Moroccan population. In Tunisia, the incidence of p.P533R mutation seems to be associated with the high frequency of consanguineous marriages. CONCLUSION: The identification of known MPS I mutations (p.P533R and p.R628X) and of the novel mutation p.F602X permits reliable genetic counselling of at-risk relatives and molecular prenatal diagnosis.

[Diagnostic strategy of mucopolysaccharidosis type I in Tunisia]. / La mucopolysaccharidose de type I: stratégie diagnostique en Tunisie.

A Tunisian patient affected by mucopolysaccharidosis (MPS) was investigated for a biological analysis (quantitative and qualitative glycosaminoglycans (GAG) screening). We have also done an enzymatic determination of alpha-L-iduronidase activity (IDUA). The most common mutation (p.Gln 70 X, p.Trp 402X and p.Pro 533 Arg) were researched by an enzymatic restriction and sequencing of the IDUA gene. Enzymatic and urinary diagnostics suggested a MPS I phenotype. The patient investigated had the mutation p.Pro 533 Arg in the homozygous status, whereas his parents were heterozygous for this mutation.

[Current development and usefulness of biomarkers for Gaucher disease follow up]. / Actualité et utilité des biomarqueurs pour le suivi de la maladie de Gaucher.

Gaucher's disease is due to glucocerebrosidase deficiency which is responsible for the accumulation of non degraded glucosylceramide within the lysosomes of macrophages: these "Gaucher cells", overloaded and alternatively activated, release in patient's plasma numerous compounds (cytokines, chemokines, hydrolases...) some of which contribute to the various tissue damages. Some of these compounds are surrogate biomarkers which contribute to the evaluation of disease severity, progression and stabilisation or regression during treatment. To date, the most interesting biomarkers are chitotriosidase and the chemokine CCL18/PARC, especially in chitotriosidase deficient patients. These biomarkers together with the clinical evaluation help to therapeutic choice (treatment by enzyme replacement therapy or substrate reduction therapy) and initiation decision, response follow-up and dose adjustments. Biomarkers should be assessed every 12 months together with clinical evaluation in patients not receiving specific treatments. An assessment every 3 months is recommended during the first year of treatment. Then when clinical goals have been achieved, the frequency can be reduced to every 12 months if the therapeutic scheme is not modified.

Genetic heterogeneity of the GLDC gene in 28 unrelated patients with glycine encephalopathy.

Glycine encephalopathy, or nonketotic hyperglycinaemia (NKH; Mckusick 238300) is a severe autosomal recessive disease due to a defect in the glycine cleavage system (GCS), which is a complex of four subunits: P-, T-, H- and L-proteins. A P-protein (glycine decarboxylase or GLDC) deficiency was reported in about 80% of NKH patients. We performed mutation analysis of the complete coding sequence of the GLDC gene in 28 unrelated patients with neonatal NKH using denaturing high-performance liquid chromatography (DHPLC) and sequencing. Forty different gene alterations were identified, confirming the large molecular heterogeneity of the GLDC gene. Eighteen alterations were clearly disease-causing: two large deletions, four one-base deletions (c.28delC, c.1175delC, c.2186delC, c.2422delA), one 1-base insertion (c.1002_1003insT), one 4-base insertion (c.1285_1286insCAAA), one insertion/deletion (c.2153_2155delinsTCCTGGTTTA), five nonsense mutations (p.E153X, p.R236X, p.E270X, p.R337X, p.R424X) and four splice site mutations (c.861+1G > T, c.1402-1C > G, c.2316-1G > A, c.2919+1G > A). Additionally, we identified one intronic mutation outside the consensus splice sites (c.2838+5G > A) and 21 nucleotide substitutions leading to amino acid change (including three previously described mutations: p.T269M, p.R461Q, p.G771R), the pathogenicity of which should be confirmed by expression studies (p.S132W, p.Y138F, p.G171A, p.T187K, p.R212K, p.T269M, p.R373W, p.I440N, p.R461Q, p.N533Y, p.C644F, p.H651R, p.V705M, p.N732K, p.G771R, p.H775R, p.T830M, p.A841P, p.D880V, p.S957P and p.R966G). Mutation analysis allowed us to identify sequence alterations in both alleles for 19 patients and in one allele for 7 patients One patient was carrying three mutations (p.Y138F, p.T269M and p.E153X) and one patient was carrying two amino acid substitutions on the same allele (p.V705M and p.R212K) and an unidentified mutation on the other allele. No mutation could be found in two patients, suggesting possible defects in the H-protein or gene alterations that could not be identified by our technique. The potential use of genotype determination for prenatal diagnosis is emphasized.

Early diagnosis of mucopolysaccharidosis III A with a nonsense mutation and two de novo missense mutations in SGSH gene.

An early presentation of heparan N-sulphatase (SGSH) deficiency (mucopolysaccharidosis IIIA, MPS IIIA) with a prominent and isolated hepato-splenomegaly is described. Molecular analysis detected a nonsense mutation (Y40X) and two de novo missense mutations (E300V; Q307P).

Clinical, morphological, and molecular aspects of sialic acid storage disease manifesting in utero.

BACKGROUND: Sialic acid storage diseases (SASDs) are caused by the defective transport of free sialic acid outside the lysosome. Apart from the Salla presentation in Finland, SASD is a very rare form of lysosomal storage disease (LSD) with approximately 35 cases, all diagnosed after birth, having been reported worldwide. We report a series of 12 French patients with very early manifestations, including eight fetuses diagnosed in utero. RESULTS: Ultrasound examination, fetal autopsy, or clinical examination showed prominent ascites, rarely progressing to complete hydrops, and highlighted the early severity of bone disease. Dramatic increase of free sialic acid in various biological samples confirmed the diagnosis in all cases. Storage staining affinities and storage distribution in placenta and fetal organs allowed differential diagnosis from other LSDs but cannot differentiate between SASD, sialidosis, and galactosialidosis. Fourteen different mutations were identified, showing the molecular heterogeneity of SASD in the French population. We found that the previously described p.Y306X mutation generated two different transcripts, and we identified seven novel mutations: three deletions (del exon 7, del exons10+11 and c.1296delT), one splice site mutation (c.1350+1G-->T) one nonsense mutation (p.W339X), and two missense mutations (p.R57C and p.G127E). CONCLUSIONS: The severity of our patients' genotypes is in agreement with their phenotypes but not with the importance and early appearance of the very frequent in utero manifestations. Minimal fetal disease in some patients and a reported case of heterogeneity of fetal involvement within a family suggest that factors other than the genotype influence fetal manifestations.

Localisation of a gene for mucopolysaccharidosis IIIC to the pericentromeric region of chromosome 8.

Mucopolysaccharidosis type IIIC (MPS IIIC, or Sanfilippo syndrome C) is a rare lysosomal storage disorder caused by a deficiency of acetyl-coenzyme A:alpha-glucosaminide-N-acetyltransferase. Patients develop progressive neuropsychiatric problems, mental retardation, hearing loss, and relatively minor visceral manifestations. The pattern of transmission is consistent with an autosomal recessive mode of inheritance. The aim of this study was to find a locus for MPS IIIC using a homozygosity mapping approach. A genomewide scan was performed on DNA from 27 affected individuals and 17 of their unaffected relatives. Additional patients were recruited, and DNA was obtained from a total of 44 affected individuals and 18 unaffected family members from 31 families from 10 countries. A working candidate interval was defined by looking for excess homozygosity in patients compared with their relatives. Additional markers were genotyped in regions of interest. Linkage analysis was performed to support the informal analysis. Inspection of the genomewide scan data showed apparent excess homozygosity in patients compared with their relatives for markers on chromosome 8. Additional genotyping identified 15 consecutive markers (from D8S1051 to D8S2332) in an 8.3 cM interval for which the genotypes of affected siblings were identical in state. A maximum multipoint lod score of 10.61 was found at marker D8S519. A locus for MPS IIIC maps to an 8.3 cM (16 Mbp) interval in the pericentromeric region of chromosome 8.

[Application of tandem mass spectrometry to neonatal screening of inherited metabolic diseases: focus on present developments]. / La spectrométrie de masse en tandem appliquée au dépistage néonatal des maladies héréditaires du métabolisme: le point sur les utilisations actuelles.

The recent evolution of tandem mass spectrometry allows to diagnose more than twenty inherited metabolic diseases within a single blood spot. Nowadays, it is technically possible to screen newborns for most of fatty acid oxidation, organic acid and amino acid disorders. An important number of prospective pilot studies, using tandem mass spectrometry, have been done worldwide. However, several technical, economical, medical and ethical problems are raised by these applications. This review is intended to focus on this technology and to resume results from the main international studies.

[Analysis of 12 cases of McArdle's disease diagnosed after 30 years]. / Maladie de MacArdle diagnostiquée après 30 ans : à propos de 12 cas.

PURPOSE: McArdle's disease (MAD) or glycogen storage disease type V, usually starts in childhood or adolescence. Generally diagnosis is made before the early adulthood because patients present well defined syndrome and are constrained. METHOD: We retrospectively investigated all MAD cases diagnosed in the biochemical laboratory from Debrousse Hospital in Lyon, during 40 years (1962-2002). We then selected patients whose diagnosis had been made after 30 years. RESULTS: Fifteen patients answered our criteria but only 11 files could be analysed. A twelfth patient (service of internal medicine--Royan) supplemented the series. We sought the reasons of a late diagnosis: early age of beginning but few symptoms (7 cases), age of beginning higher than 20 years (5 cases including 3 after 45 years). The principal symptoms were muscular deficit and muscular pains (8 cases) and second wind phenomenon (7 cases). Creatinine phosphokinase level was constantly high. Ischemic effort test when it was carried out was constantly abnormal. Conversely electromyogram was often normal (5 cases). Several biopsies were necessary in a third of the cases to evoke the diagnosis, particularly among the patients with late onset symptoms. CONCLUSION: Diagnosis of metabolic MAD is generally easy if the interrogation finds inaugural symptoms in childhood or adolescence even if the patient consults very late in the life. The diagnosis can become much more difficult if it begins late in life (atypical symptoms, need for several muscular biopsy).

Perinatal-lethal Gaucher disease.

Gaucher disease is a lysosomal storage disease caused by glucocerebrosidase deficiency. Although purely visceral in most cases, some Gaucher disease patients have neurological signs. Signs of Gaucher disease appear after a symptom-free period, except in rare cases with fetal onset. The description of such cases was based mainly on single reports and siblings. We report here a series of perinatal-lethal Gaucher disease cases highlighting the specificity of this phenotype. We retrospectively studied eight original cases of proven Gaucher disease with fetal onset. Non-immune hydrops fetalis was present in all cases but one, and associated with hepatosplenomegaly, ichthyosis, arthrogryposis, and facial dysmorphy. The similarities between our cases and 33 previously described cases allow us to better delineate the perinatal-lethal Gaucher disease phenotype. Hydrops fetalis, in utero fetal death and neonatal distress are prominent features. When hydrops is absent, neurological involvement begins in the first week and leads to death within three months. Hepatosplenomegaly is a major sign, and associated with ichthyosis, arthrogryposis, and facial dysmorphy in some 35-43% of cases. Perinatal-lethal Gaucher disease is a specific entity defined by its particular course and signs that are absent in classical type 2 Gaucher disease. Our study provides clues to the diagnosis of this likely underdiagnosed condition, which must be biochemically confirmed in order to propose appropriate genetic counselling.

Outcome of 27 patients with Hurler's syndrome transplanted from either related or unrelated haematopoietic stem cell sources.

Over the last 15 years, we have performed a total of 30 haematopoietic stem cell transplants on 27 children suffering from Hurler's syndrome. These children were of median age 11 months at the time of diagnosis and 25 months at the time of transplantation. The phenotype was severe in 21 cases (78%). The donor was familial in 13 cases: nine genotypically identical, one phenotypically identical father and three HLA-mismatched donors. Unrelated donors were selected in 17 cases: four phenotypically identical and 13 with 1-4 HLA mismatches. The conditioning regimen generally consisted of busulphan 600 mg/m(2) plus cyclophosphamide (Endoxan) 260 mg/kg and cyclosporin with methotrexate for GvHD prophylaxis. Rabbit anti-thymocyte globulin (Thymoglobuline) was given for all unrelated or familial mismatched transplantations. The median nucleated cell dose infused was 6.00 x 10(8) TNC/kg. No bone marrow (apart from one) was T cell depleted. For first transplants, engraftment was observed in 23/27 patients (pts) (85%). Primary graft failure was observed in 4/27 patients (16%), two were retransplanted from an unrelated donor, one with success. Four patients have died. The primary cause of death was infection in three cases (TRM : 11%) and disease progression in one case, after primary graft failure. Of the 23 living patients, two have disease progression after graft failure and 21 (78%) have functional grafts with a favourable long-term outcome after a median follow-up of 4.7 years, having either full or mixed chimaerism. Among surviving patients with functional grafts, 13 (62%) were transplanted from unrelated donors of whom 10 (77 %) had HLA disparities. There was a remarkably low incidence of GvHD. In our experience, haematopoietic stem cell transplantation using an HLA-matched familial donor or an HLA-matched or -mismatched unrelated donor without T cell depletion or irradiation can achieve a favourable outcome in Hurler's syndrome, with improved cognitive function, but with a limited effect on the corneas and skeleton.