Clinical outcomes after 4.5 years of eliglustat therapy for Gaucher disease type 1: Phase 3 ENGAGE trial final results.

Eliglustat, an oral substrate reduction therapy, is approved for eligible adults with Gaucher disease type 1. In the Phase 3 ENGAGE trial of previously untreated adults with Gaucher disease type 1, eliglustat-treated patients had statistically significant improvements in organ volumes and hematologic parameters compared with placebo in the 9-month primary analysis. We report final outcomes by time on eliglustat among all patients who participated in the ENGAGE trial and extension. No patient deteriorated clinically or withdrew due to adverse events; 39/40 patients entered the open-label extension period and 34/40 (85%) remained in the trial until completion or switching to commercial eliglustat after its approval (2.3-6 years). Clinically meaningful improvements in Gaucher disease manifestations were seen in all patients concomitant with reductions in pathological lipid substrate levels (glucosylceramide and glucosylsphingosine). Among patients with 4.5 years of eliglustat exposure, mean spleen volume decreased by 66% (from 17.1 to 5.8 multiples of normal [MN], n = 13), mean liver volume decreased by 23% (from 1.5 to 1.1 MN, n = 13), mean hemoglobin increased 1.4 g/dl (from 11.9 to 13.4 g/dl, n = 12), mean platelet count increased by 87% (from 67.6 to 122.6 × 109 /L, n = 12), median chitotriosidase decreased by 82% (from 13 394 to 2312 nmol/h/ml, n = 11), median glucosylceramide decreased by 79% (from 11.5 to 2.4 µg/ml, n = 11), median glucosylsphingosine decreased by 84% (from 518.5 to 72.1 ng/ml, n = 10), and mean spine T-score increased from -1.07 (osteopenia) to -0.53 (normal) (n = 9). The magnitude of improvement in Gaucher disease manifestations and biomarkers over time was similar among the full trial cohort. Eliglustat was well-tolerated and led to clinically significant improvements in previously untreated patients with Gaucher disease type 1 during 4.5 years of treatment.

High Frequency of Cardiovascular Complications in Tunisian Kawasaki Disease Patients: Need for a Further Awareness.

BACKGROUND: The outcome of Kawasaki disease (KD) depends on cardiovascular complications (CVCs). OBJECTIVES: This study aimed to explore diagnostic features and CVCs in Tunisian patients with KD. METHODS: In total, 33 Tunisian patients (age, 2.9 ± 2.2 years) fulfilling the diagnosis criteria of KD, were retrospectively reviewed. Nonparametric tests were used to compare the two groups with regards to coronary complications (CCs). RESULTS: Diagnosis of KD was established at day 11 ± 5.1 from the beginning of the fever. Apyrexia was obtained in an average of 29 h after completion of intravenous immunoglobulin. CVCs were identified in 52% of cases: CC in 15 patients (giant aneurysm >8 mm in five patients) and non-CCs in 6 patients (severe in three patients). CCs were more frequently associated with the male sex (p = 0.037), fever lasting >8 days (p = 0.028) and longer time to apyrexia (p = 0.031). CONCLUSION: In Tunisia, better knowledge and monitoring of KD are warranted.

Outcomes after 18 months of eliglustat therapy in treatment-naïve adults with Gaucher disease type 1: The phase 3 ENGAGE trial.

Eliglustat, an oral substrate reduction therapy, is a first-line treatment for adults with Gaucher disease type 1 (GD1) who are poor, intermediate, or extensive CYP2D6 metabolizers (>90% of patients). In the primary analysis of the Phase 3 ENGAGE trial (NCT00891202), eliglustat treatment for 9 months resulted in significant reductions in spleen and liver volumes and increases in hemoglobin concentration and platelet count compared with placebo. We report 18-month outcomes of patients who entered the trial extension period, in which all patients received eliglustat. Of 40 trial patients, 39 entered the extension period, and 38 completed 18 months. Absolute values and percent change over time were determined for spleen and liver volume, hemoglobin concentration, platelet count, bone mineral density, bone marrow burden, and Gaucher disease biomarkers. For patients randomized to eliglustat in the double-blind period, continuing treatment with eliglustat for 9 more months resulted in incremental improvement of all disease parameters. For patients randomized to placebo in the double-blind period, eliglustat treatment during the 9-month, open-label period resulted in significant decrease of spleen and liver volumes and significant increase of hemoglobin and platelets, with a similar rate of change to patients who had received eliglustat in the double-blind period. Eliglustat treatment was also associated with improvement in bone marrow burden score, bone mineral density, and established biomarkers of Gaucher disease, including reduction of the bioactive lipid, glucosylsphingosine. These findings underscore the efficacy of eliglustat in treatment-naïve patients. Eliglustat was well-tolerated, and there were no new safety concerns with longer-term exposure.

A de-novo large deletion of 2.8 kb produced in the ABCD1 gene causing adrenoleukodystrophy disease.

X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder caused by mutations in the ABCD1 gene, which encodes an ATP-binding cassette transporter protein, ALDP. The disease is characterized by increased concentrations of very long chain fatty acids (VLCFAs) in plasma, adrenal, testicular, and nerve tissues. For this study, our objective was to conduct clinical, molecular, and genetic studies of a Tunisian patient with X-ALD. The diagnosis was based on clinical indications, biochemical analyses, typical brain-scan patterns, and molecular biology; the molecular analyses were based on PCR, long-range PCR, and sequencing. The molecular analysis by long-range PCR and direct sequencing of the ABCD1 gene showed the presence of a de-novo 2794 bp deletion covering the whole of exon 2. Using bioinformatics tools, we demonstrate that the large deletion is located in a region rich with Alu sequences. Furthermore, we suggest that the AluJb sequence could be the cause of the large deletion of intron 1, exon 2, and intron 2, and the creation of a premature stop codon within exon 3. This report is the first report in which we demonstrate the breakpoints and the size of a large deletion in a Tunisian with X-ALD.

Effect of oral eliglustat on splenomegaly in patients with Gaucher disease type 1: the ENGAGE randomized clinical trial.

IMPORTANCE: Gaucher disease type 1 is characterized by hepatosplenomegaly, anemia, thrombocytopenia, and skeletal disease. A safe, effective oral therapy is needed. OBJECTIVE: To determine whether eliglustat, a novel oral substrate reduction therapy, safely reverses clinical manifestations in untreated adults with Gaucher disease type 1. DESIGN, SETTING, AND PARTICIPANTS: Phase 3, randomized, double-blind, placebo-controlled trial conducted at 18 sites in 12 countries from November 2009 to July 2012 among eligible patients with splenomegaly plus thrombocytopenia and/or anemia. Of 72 patients screened, 40 were enrolled. INTERVENTIONS: Patients were stratified by spleen volume and randomized 1:1 to receive eliglustat (50 or 100 mg twice daily; n = 20) or placebo (n = 20) for 9 months. MAIN OUTCOMES AND MEASURES: The primary efficacy end point was percentage change in spleen volume in multiples of normal from baseline to 9 months; secondary efficacy end points were change in hemoglobin level and percentage changes in liver volume and platelet count. RESULTS: All patients had baseline splenomegaly and thrombocytopenia (mostly moderate or severe), most had mild or moderate hepatomegaly, and 20% had mild anemia. Least-square mean spleen volume decreased by 27.77% (95% CI, -32.57% to -22.97%) in the eliglustat group (from 13.89 to 10.17 multiples of normal) vs an increase of 2.26% (95% CI, -2.54% to 7.06%) in the placebo group (from 12.50 to 12.84 multiples of normal) for an absolute treatment difference of -30.03% (95% CI, -36.82% to -23.24%; P < .001). For the secondary end points, the least-square mean absolute differences between groups all favored eliglustat, with a 1.22-g/dL increase in hemoglobin level (95% CI, 0.57-1.88 g/dL; P < .001), 6.64% decrease in liver volume (95% CI, -11.37% to -1.91%; P = .007), and 41.06% increase in platelet count (95% CI, 23.95%-58.17%; P < .001). No serious adverse events occurred. One patient in the eliglustat group withdrew (non-treatment related); 39 of the 40 patients transitioned to an open-label extension study. CONCLUSIONS AND RELEVANCE: Among previously untreated adults with Gaucher disease type 1, treatment with eliglustat compared with placebo for 9 months resulted in significant improvements in spleen volume, hemoglobin level, liver volume, and platelet count. The clinical significance of these findings is uncertain, and more definitive conclusions about clinical efficacy and utility will require comparison with the standard treatment of enzyme replacement therapy as well as longer-term follow-up. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00891202.

Velaglucerase alfa enzyme replacement therapy compared with imiglucerase in patients with Gaucher disease.

Enzyme replacement therapy for Gaucher disease (GD) has been available since 1991. This study compared the efficacy and safety of velaglucerase alfa with imiglucerase, the previous standard of care. A 9-month, global, randomized, double-blind, non-inferiority study compared velaglucerase alfa with imiglucerase (60 U/kg every other week) in treatment-naïve patients aged 3-73 years with anemia and either thrombocytopenia or organomegaly. The primary endpoint was the difference between groups in mean change from baseline to 9 months in hemoglobin concentration. 35 patients were randomized: 34 received study drug (intent-to-treat: 17 per arm), 20 were splenectomized. Baseline characteristics were similar in the two groups. The per-protocol population included 15 patients per arm. The mean treatment difference for hemoglobin concentration from baseline to 9 months (velaglucerase alfa minus imiglucerase) was 0.14 and 0.16 g/dL in the intent-to-treat and per-protocol populations, respectively. The lower bound of the 97.5% one-sided confidence interval in both populations lay within the pre-defined non-inferiority margin of -1.0 g/dL, confirming that velaglucerase alfa is non-inferior to imiglucerase. There were no statistically significant differences in the secondary endpoints. Most adverse events were mild to moderate. No patient receiving velaglucerase alfa developed antibodies to either drug, whereas four patients (23.5%) receiving imiglucerase developed IgG antibodies to imiglucerase, which were cross-reactive with velaglucerase alfa in one patient. This study demonstrates the efficacy and safety of velaglucerase alfa compared with imiglucerase in adult and pediatric patients with GD clinically characterized as Type 1. Differences in immunogenicity were also observed.

Molecular characterization of X-linked adrenoleukodystrophy in a Tunisian family: identification of a novel missense mutation in the ABCD1 gene.

BACKGROUND: X-linked adrenoleukodystrophy (X-ALD) is a recessive neurodegenerative disorder that affects the brain's white matter and is associated with adrenal insufficiency. It is characterized by an abnormal function of the peroxisomes, which leads to an accumulation of very long-chain fatty acids (VLCFA) in plasma and tissues, especially in the cortex of the adrenal glands and the white matter of the central nervous system, causing demyelinating disease and adrenocortical insufficiency (Addison's disease). X-ALD is caused by a mutation in the ABCD1 gene (ATP-binding cassette, subfamily D, member 1), which encodes the adrenoleukodystrophy protein involved in the transport of fatty acids into the peroxisome for degradation. OBJECTIVE: We report here a disease-related variant in the ABCD1 gene in a 19-year-old Tunisian boy with childhood cerebral adrenoleukodystrophy. METHODS: The diagnosis was based on clinical symptoms, high levels of VLCFA in plasma, typical MRI pattern and molecular analysis. RESULTS: Molecular analysis by direct sequencing of the ABCD1 gene showed the presence of a novel missense mutation c.284C>A (p.Ala95Asp) occurring in the transmembrane domain in the proband, his mother and his sister. CONCLUSION: Using bioinformatic tools we suggest that this novel variant may have deleterious effects on adrenoleukodystrophy protein structure and function.

Fulminant Neonatal Liver Failure in MPV 17-Related Mitochondrial DNA Depletion Syndrome.

Mitochondrial depletion syndromes are well established causes of liver failure in infants. Hepatocerebral variant related to MPV17 gene defect is characterized by infantile onset of progressive liver failure, developmental delay, neurological manifestations, lactic acidosis, hypoglycemia, and mtDNA depletion in liver tissue. We report a hepatocerebral variant of mitochondrial DNA depletion syndrome in a neonate who presented with septic shock picture, hypoglycemia, jaundice, hypotonia, and rotatory nystagmus. Family history was significant for consanguinity and a brother who died at the age of 4 months. Investigations showed mild liver function derangement contrasting with severe coagulopathy, hyperlactatemia, and generalized aminoaciduria. The brain MRI was normal. Next generation sequencing (NGS) panel identified a MPV17 gene missense homozygous pathogenic variant. The infant expired at the age of 2 weeks with refractory ascites. This case illustrates a challenging diagnosis causing liver failure and death in neonatal period. Genetic testing of mitochondrial DNA depletion syndromes should be a part of liver failure workup in addition to other treatable disorders presenting with encephalo-hepatopathy in infancy.

To What Extent Does Arginine Reduce the Risk of Developing Necrotizing Enterocolitis?

Necrotizing enterocolitis (NEC) and neonatal sepsis are polar opposite diseases that are commonly encountered in the NICU. Concerning the frequency of these pathologies, NEC is regarded as being a much rarer condition, whereas neonatal sepsis is slightly more commonly encountered. However, neonatal sepsis can present with varying clinical presentations and, if caught late, can be detrimental to the patient. Many different modes of therapies have been studied for both conditions at different levels of pathologies, from a microscopic to a macroscopic level, leading to an assessment of treatment approaches. With the different ongoing treatment protocols being studied, one such therapy under investigation that does stand out is the use of L-arginine in both conditions. The L-arginine, being an essential amino acid, has many basic biological roles in developing neonates. It mainly involves the production of nitric oxide (NO), a potent vasodilator, which is particularly important in the development of vasculature in almost every organ. In premature infants, poorly developed vasculature makes them more susceptible to injury, therefore increasing the risk of diseases such as NEC and the severity of diseases such as neonatal sepsis. By assessing the uses of L-arginine and its application towards treating conditions like NEC and neonatal sepsis, we aim to identify its potential benefits as a treatment and its potential applications in clinical practice by understanding its basic functions and role in the pathophysiology of NEC and neonatal sepsis.

[A novel mutation in PEX 26 gene in Zellweger syndrome: a case report]. / Syndrome de Zellweger par une nouvelle mutation du gène PEX 26.

BACKGROUND: Zellweger syndrome is the most severe phenotype of the peroxisome biogenesis disorders caused by mutations in PEX genes. PEX 1, 6 and 26 genes are most frequently implicated. Clinical phenotype can't predict the mutated gene. AIM: To report a novel mutation in the PEX 26 gene in infant with typical Zellweger syndrome. CASE REPORT: the infant was the second child to consanguineous parents; the 1st child was dead with neonatal hypotonia. At two month of age, we noted a severe hypotonia and growth failure, characteristic facial dysmorphic features and cryptorchidism. Sensorial investigations showed optic atrophy. Cerebral tomography revealed white matter hypodensity. Radiological examination revealed calcific stippling of the patellas. The clinical diagnosis was supported by measurement of plasma very-long-chain fatty acids, with elevated C24:0/C22:0, C26:0/C22:0 ratios and decreased docosanoic acid peak. The diagnosis was confirmed by dosage of DHAP-AT activity in fibroblasts which was very low. Ultrastructural examinations showed the presence of peroxisomal ghosts. Genetic analysis demonstrated a new mutation in PEX 26 gene.The death occurred at the age of 8 months of refractor epilepsy and apneas. CONCLUSION: The poor prognosis of ZS incites paediatricians to consider this disorder in etiological investigations of precocious hypotonia. Biochemical diagnosis, available in Tunisia, offers opportunity of prenatal diagnosis in affected families.

[Rosai -Dorfman disease: a two cases report]. / La maladie de Rosai ­ Dorfman : a propos de deux observations.

BACKGROUND: Rosai-Dorfman disease (RDD) is a benign lymphoproliferatif disorder characterized by cervical lymphadenopathies with a consistent risk of airways' compression and esthetical prejudice. Extra nodal localizations are also described. AIM: To report two pediatric cases of RDD. CASES: the first case concerned a patient with a prolonged nodal involvement of RDD. Remission seems to be natural although it coincided with a sulfaméthoxazole- triméthoprime therapy. The second case illustrated an extranodal form of RDD localized in soft tissue and paranasal sinus with extension to nasal cavity which were corticodependant. CONCLUSION: RDD is usually a benign disorder. Particular localizations, lack of effective therapy and the high risk of recurrence are important issues in this rare affection.

Congenital hyperinsulinism: review of 12 Tunisian cases.

BACKGROUND: Congenital hyperinsulinism in infancy (CHI) is a heterogeneous disorder with respect to genetics and response to therapy. Data on CHI are sporadic in North African population. AIM: To characterize the clinical features and outcome of 12 Tunisian patients with CHI. METHODS: data of patients diagnosed with CHI during the period 1989-2007 were retrospectively analyzed. Diagnosis was considered whenever hyperinsulinemia ≥ 10µ UI/ml was concomitant to hypoglycemia < 3mmol/l and/or high insulin to glucose ratio > 0.3 and/or positif glucagon test. Transient causes of hypoglycemia, adrenal and growth hormone deficiency were excluded. RESULTS: There were nine infants diagnosed at a median age of 17 months and three newborns. Permanent hyperammoniemia, found in one patient, guided to leucine-sensitive hyperinsulinism. Seven patients presented with seizures, two with psychomotor delay and one with recurrent malaises. Among 42 assays of plasmatic insulin, when in hypoglycemia, 40% only were ≥ 10µU/ml. Three patients resisted to diazoxide and underwent subtotal pancreatectomy complicated by diabetes mellitus in two cases and persistent hypoglycemia in one patient. Histological examination concluded to diffuse hyperplasia of pancreatic cells. Diazoxide was discontinued in four out the eight responders' patients. Four patients died, seven patients developed variable degrees of mental retardation and five suffered from epilepsy. CONCLUSION: Early onset forms were, as reported in the literature, mostly resistant to medical therapy. The high proportion of neurological sequelae is related to diagnosis delay or to a late surgery. We focus on the importance of a precocious diagnosis and aggressive treatment of hypoglycemia.

Fucosidosis in Tunisian patients: mutational analysis and homology-based modeling of FUCA1 enzyme.

BACKGROUND: Fucosidosis is an autosomal recessive lysosomal storage disease caused by defective alpha-L-fucosidase (FUCA1) activity, leading to the accumulation of fucose-containing glycolipids and glycoproteins in various tissues. Clinical features include angiokeratoma, progressive psychomotor retardation, neurologic signs, coarse facial features, and dysostosis multiplex. METHODS: All exons and flanking intron regions of FUCA1 were screened by direct sequencing to identify mutations and polymorphisms in three unrelated families with fucosidosis. Bioinformatics tools were then used to predict the impacts of novel alterations on the structure and function of proteins. Furthermore, the identified mutations were localized onto a 3D structure model using the DeepView Swiss-PdbViewer 4.1 software, which established a function-structure relationship of the FUCA1 proteins. RESULTS: Four novel mutations were identified in this study. Two patients (P1 and P2) in Families 1 and 2 who had the severe phenotype were homoallelic for the two identified frameshift mutations p.K57Sfs*75 and p.F77Sfs*55, respectively. The affected patient (P3) from Family 3, who had the milder phenotype, was heterozygous for the novel missense mutation p.G332E and the novel splice site mutation c.662+5g>c. We verified that this sequence variation did not correspond to a polymorphism by testing 50 unrelated individuals. Additionally, 16 FUCA1 polymorphisms were identified. The structure prediction analysis showed that the missense mutation p.G332E would probably lead to a significant conformational change, thereby preventing the expression of the FUCA1 protein indeed; the 3D structural model of the FUCA1 protein reveals that the glycine at position 332 is located near a catalytic nucleophilic residue. This makes it likely that the enzymatic function of the protein with p.G332E is severely impaired. CONCLUSION: These are the first FUCA1 mutations identified in Tunisia that cause the fucosidosis disease. Bioinformatics analysis allowed us to establish an approximate structure-function relationship for the FUCA1 protein, thereby providing better genotype/phenotype correlation knowledge.

[Phenotype and mutational spectrum in Tunisian pediatric gaucher disease]. / Phénotype clinique et spectre mutationnel de la maladie de Gaucher pédiatrique en Tunisie.

BACKGROUND: Gaucher disease (GD) is a sphingolipidosis with heterogeneous phenotypic expression. The vital and / or functional prognosis may be threatened by an early visceral severe involvement in type 1 or a neurological degeneration in the more rarest neuroneupathic forms. The phenotypic and genotypic data regarding Gaucher disease are poorly known in Maghrebian countries; they are even less for pediatric forms. THE AIM of the study is to highlight the specific phenotypic and genotypic changing among the widest Gaucher pediatric cohort in the Tunisian population. METHODS: a restrospective study of a sample oh children in voluved by gaucher disease. RESULTS: Twenty one cases of GD were identified, divided into 13 cases with type 1, 5 with type 3 and 3 children with acute neurological form. The first symptoms occurred before 1 year age in one third of patients with type IGD. The clinical phenotype was severe according to the high severity score index and proportion of growth retardation. Portal hypertension was found in 8 patients. Three type 3 GD patients died before occurrence of the neurological signs. The phenotype was intermediate between the classic type 2 GD and its perinatal lethal variant. Three patients were treated with enzyme replacement therapy and 4 others had allogenic bone marrow transplantation with a favorable outcome. Three mutations dominate the genotypic spectrum of GD in this cohort. Additionally to the N370 mutation, L444P and RecNciI mutations seem to occur more frequently compared to the GD forms presenting in adulthood. CONCLUSION: This data confirm the particular severity of Gaucher disease manifesting in childhood. This was enhanced through the high frequency of severe mutations. Further studies on largest cohort are needed to more clarify the phenotypic and genotypic features of Gaucher disease in Tunisia.

Incidence of mucopolysaccharidoses in Tunisia.

BACKGROUND: The mucopolysaccharidoses (MPS) are a devastating heterogenous group of lysosomal storage disorders. AIM: To evaluate the epidemiological profile of MPS in Tunisia. METHODS: we conducted a retrospective epidemiological survey covering the period 1970-2005. Multiple sources were used to identify affected patients. RESULTS: Ninety six confirmed MPS cases were collected from 132 suspected cases found in the surveyed data. Of the ninety six confirmed cases, 20% were from multiplex families. Consanguinity was found in 83% of the families. The crude rate for all types of mucopolysaccharidoses was 2.3 cases in 100,000 live births. The prevalence of MPS type I, III and IV, those most frequently occurring in the collected data, were estimated at 0.63, 0.7 and 0.45 per 100,000 live births, respectively. The cumulative incidence of MPS type VI (0.3 per 105 live births) was higher than reported in European countries; but, it is likely that... CONCLUSION: The reported frequency of all types of MPS in Tunisia is underestimated.

[Enzyme replacement therapy for Gaucher paediatric disease: the only Tunisian experience]. / Traitement enzymatique substitutif de la maladie de Gaucher chez l'enfant: premiere experience Tunisienne.

AIM: We report through the first Tunisian experience with enzyme replacement therapy, the goals and consensus recommendations for treatment and monitoring of paediatric non neuronopathic Gaucher disease. METHODS: Three children with Gaucher disease undergone enzyme replacement therapy with Cerezyme for severe visceral and/or bone involvement. Visceral, hematologic, bone, and growth parameters were assessed initially and under treatment. RESULTS: Two children presented with severe visceral or hematologic picture. One patient had myocardiopathy and primitive portal hypertension and another was diagnosed with cirrhosis related to Gaucher disease. Recurrent avascular necrosis and osteoporosis have justified treatment in another child. All patients received an initial dose of 60U/Kg/2 weeks. We have seen a gradual disappearance of hepatosplenomegaly and a rapid normalisation of hematological parameters in two patients. A resistance to treatment indicated splenectomy in one patient. The improvement in bone mineral density was slower. A significant growth gain was observed in patients with growth retardation. No patient had developed Cerezyme antibodies. CONCLUSION: Despite its effectiveness and safety demonstrated in these children, enzyme replacement therapy remains inaccessible because of its cost for emerging countries. The allogeneic bone marrow is an alternative therapy to encourage and to propose precociously for severe paediatric forms of Gaucher disease.

A novel homozygous missense mutation in the insulin receptor gene results in an atypical presentation of Rabson-Mendenhall syndrome.

Leprechaunism (Donohue syndrome) and Rabson-Mendenhall syndrome are caused by mutations in the insulin receptor gene and are associated with extreme insulin resistance. Clinically these syndromes appear to represent points on a continuum of severity of receptor dysfunction, rather than completely distinct syndromes. We investigated a Libyan infant with growth retardation, facial dysmorphism (elfin-like features), acanthosis nigricans and hirsutism. Fasting hypoglycaemia and postprandial hyperglycaemia with persistent hyperinsulinemia were found. A novel homozygous missense mutation was found in exon 2, resulting in a substitution of a glycine-132 for a serine in the INSR α-subunit (c.394G > A; p.Gly132Ser). At age ten, he developed diabetes mellitus. At age eleven, patient is still alive with mental retardation and severe growth retardation.

Molecular analysis in a GALNS study cohort of 15 Tunisian patients: description of a novel mutation.

BACKGROUND: Mucopolysaccharidosis type IVA (MPS IVA) is an autosomal recessive disease caused by the deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS). The purpose of this study was to analyze the GALNS mutations and the haplotypes associated. METHODS: Mutation screening of the GALNS gene was performed by direct sequence analysis using DNA samples from 15 unrelated Tunisian MPS IVA patients. We also analyzed the haplotypes associated with the novel mutation and with the other reported GALNS mutations. RESULTS: We have identified an unreported missense mutation p.D288G (c.863A > G) in one patient, the most frequently c.120 + 1G > A (IVS1 + 1G > A) mutation in eleven MPS IVA patients and three previously reported mutations p.G66R, p.A85T and p.R386C on the other MPS IVA patients. All the studied patients were homozygous for these identified mutations. Bioinformatics analysis predicted the novel mutation as being probably pathogenic. These findings with the unobserved p.D288G mutation in controls subjects, suggested that it is a disease-causing mutation, which was correlated with the severe phenotype observed in the patients. We have found that the two GALNS unreported and reported mutations, respectively p.D288G and p.R386C, were associated with a common and specific haplotype. CONCLUSION: Our results were in agreement with previous reports from Tunisia, suggesting, on one hand the genotype/phenotype correlations in MPS IVA patients and the other hand the haplotype analyses were useful for determination of mutation origin in Tunisian population.

Splicing defects in ABCD1 gene leading to both exon skipping and partial intron retention in X-linked adrenoleukodystrophy Tunisian patient.

X-linked adrenoleukodystrophy (X-ALD) affects the nervous system white matter and adrenal cortex secondary to mutations in the ABCD1 gene that encodes a peroxisomal membrane protein: the adrenoleukodystrophy protein. The disease is characterized by high concentrations of very long-chain fatty acids in plasma, adrenal, testicular and nervous tissues. Various types of mutations have been identified in the ABCD1 gene: point mutations, insertions, and deletions. To date, more than 40 point mutations have been reported at the splice junctions of the ABCD1 gene; only few functional studies have been performed to explore these types of mutations. In this study, we have identified de novo splice site mutation c.1780+2T>G in ABCD1 gene in an X-ALD Tunisian patient. Sequencing analysis of cDNA showed a minor transcript lacking exon 7 and a major transcript with a partial intron 7 retention due to activation of a new intronic cryptic splice site. Both outcomes lead to frameshifts with premature stop codon generation in exon 8 and intron 7 respectively. To the best of our knowledge, the current study demonstrates that a single splicing mutation affects the ABCD1 transcripts and the ALDP protein function.