Mutation Spectrum of GAA Gene in Pompe Disease: Current Knowledge and Results of an Italian Study.

Studying a patient with Pompe disease (PD) is like opening Pandora's box. The specialist is faced with numerous clinical features similar to those of several diseases, and very often the symptoms are well hidden and none is associated with this rare disease. In recent years, scientific interest in this disease has been growing more and more, but still no symptom is recognized as key to a correct diagnosis of it, nor is there any specific disease marker to date. New diagnostic/therapeutic proposals on disease allow for the diffusion of knowledge of this pathology for timely diagnosis of the patient. Due to unawareness and difficulty in diagnosis, many adults with PD are diagnosed with great delay. In this article, we report and discuss current knowledge of PD and provide new data from work conducted on a cohort of 2934 Italian subjects recruited in recent years. A genetic analysis of the GAA gene was performed on patients with significant clinical signs and pathological enzyme activity to define the genetic profile of subjects. This identified 39 symptomatic PD subjects with low acid alpha-glucosidase enzyme activity and the presence of two causative mutations in GAA gene regions. Furthermore, 22 subjects with genetic variants of uncertain significance (GVUS) were identified.

Diagnosis of Fabry Disease Using Alpha-Galactosidase A Activity or LysoGb3 in Blood Fails to Identify Up to Two Thirds of Female Patients.

Anderson-Fabry disease is a lysosomal storage disorder caused by mutations in the GLA gene, which encodes the enzyme α-galactosidase A. The GLA gene is located on the X-chromosome, causing an X-linked pathology: due to lyonization, female patients usually manifest a variable symptomatology, ranging from asymptomatic to severe phenotypes. The confirmation of the clinical diagnosis of Fabry disease, achieved by measuring α-galactosidase A activity, which is usually the first test used, shows differences between male and female patients. This assay is reliable in male patients with causative mutations in the GLA gene, in whom the enzymatic activity is lower than normal values; on the other hand, in female Fabry patients, the enzymatic activity is extremely variable between normal and pathological values. These fluctuations are also found in female patients' blood levels of globotriaosylsphingosine (LysoGb3) for the same reason. In this paper, we present a retrospective study conducted in our laboratories on 827 Fabry patients with causative mutations in the GLA gene. Our results show that 100% of male patients had α-galactosidase A activity below the reference value, while more than 70% of female patients had normal values. It can also be observed that almost half of the female patients with pathogenic mutations in the GLA gene showed normal values of LysoGb3 in blood. Furthermore, in women, blood LysoGb3 values can vary over time, as we show in a clinical case presented in this paper. Both these tests could lead to missed diagnoses of Fabry disease in female patients, so the analysis of the GLA gene represents the main diagnostic test for Fabry disease in women to date.

Gaucher disease prevalence in 600 patients affected by monoclonal gammopathy of undetermined significance.

BACKGROUND: Gaucher disease (GD) is a rare autosomal recessive inherited disorder caused by the lysosomal enzyme acid ß-glucosidase deficiency. Many patients experience a critical delay in the diagnosis of up to 8-10 years due to its rarity and variability in signs and symptoms, with the consultation of several specialists. PATIENTS AND METHODS: This prospective observational study analyzed the prevalence of GD in 600 patients with monoclonal gammopathy of uncertain significance (MGUS) from January 2018 until February 2022. RESULTS: The mean age of participants was 66 years, with a mean monoclonal component of 0.58 g/dL. In 433 MGUS patients with available data, anemia (hemoglobin level < 10 g/dL) was present in 31 patients (7%), and thrombocytopenia (platelet count <100.000/mm3 ) in 24 (5.5%). Of 600 MGUS patients tested for acid ß-glucosidase enzyme activity, 7 patients (1.2%) had activity below 2.5 nmol/h/mL. In comparison, GBA gene analysis was executed in 110 patients. It revealed 4 patients (0.7%) affected by GD (3 patients with compound heterozygous mutation and 1 with homozygous mutation), with a prevalence of 1 every 150 MGUS patients. Furthermore, 12 out of the remaining 106 evaluated patients (11%) were carriers of a single heterozygous mutation while having regular enzyme activity. CONCLUSIONS: The clinical heterogeneity of GD and frequent lack of awareness among physicians often lead to diagnostic delays and severe clinical manifestations. The role of MGUS in the presence of at least one clinical sign, such as low platelet count, organomegaly, bone pain, or bleeding tendency, could aid in initiating GD screening with DBS, thus reducing the period between symptom onset and the diagnosis of this rare disease.

Diagnosing Fabry nephropathy: the challenge of multiple kidney disease.

Fabry disease (FD) is an X-linked inherited lysosomal disorder due to a deficiency of the enzyme alpha-galactosidase A (α-gla) due to mutations in the GLA gene. These mutations result in plasma and lysosome accumulation of glycosphingolipids, leading to progressive organ damage and reduced life expectancy. Due to the availability of specific disease-modifying treatments, proper and timely diagnosis and therapy are essential to prevent irreversible complications. However, diagnosis of FD is often delayed because of the wide clinical heterogeneity of the disease and multiple organ involvement developing in variable temporal sequences. This observation is also valid for renal involvement, which may manifest with non-specific signs, such as proteinuria and chronic kidney disease, which are also common in many other nephropathies. Moreover, an additional confounding factor is the possibility of the coexistence of FD with other kidney disorders. Thus, suspecting and diagnosing FD nephropathy in patients with signs of kidney disease may be challenging for the clinical nephrologist. Herein, also through the presentation of a unique case of co-occurrence of autosomal dominant polycystic kidney disease and FD, we review the available literature on cases of coexistence of FD and other renal diseases and discuss the implications of these conditions. Moreover, we highlight the clinical, laboratory, and histological elements that may suggest clinical suspicion and address a proper diagnosis of Fabry nephropathy.

Late-Onset Pompe Disease with Normal Creatine Kinase Levels: The Importance of Rheumatological Suspicion.

Pompe disease (PD), also defined as acid maltase deficiency, is a rare autosomal recessive disease that causes glycogen accumulation due to a deficiency of the lysosomal enzyme acid α-glucosidase. An excessive amount of undisposed glycogen causes progressive muscle weakness throughout the body. It particularly affects skeletal muscles and the nervous system, especially in the late-onset phase. Here, we present a clinical case of late-onset PD (LOPD) with normal CK (creatinine kinase) values treated after a misdiagnosis of demyelinating motor polyneuropathy and chronic inflammatory neuropathy. The suspicion of possible fibromyalgia induced the patient to seek a rheumatology consultation, and the investigations performed led to the diagnosis of PD. The patient was investigated for genetic and enzymatic studies. PD was diagnosed using the α-glucosidase assay on DBS. In LOPD, clinical manifestations, such as muscle weakness, exercise intolerance, myalgia, or even high hyperCKemia, often appear as nonspecific and may mimic a wide variety of other muscle disorders, such as limb muscle dystrophies, congenital, metabolic, or inflammatory myopathies. In our case, the patient had CK values in the normal range but with continued complaints typical of PD. An analysis of enzyme activity revealed a pathologic value, and genetic analysis identified the c.-32-13T>G mutation in homozygosis. The association of the pathological enzyme value and mutation in homozygosity with LOPD led to a familial segregation study. Our results contribute to the characterization of PD in Italy and support the importance of rheumatologic attention. This suggests further studies are needed to define the broad clinical and pathological spectrum observed in this disease.

Parapelvic cysts, a distinguishing feature of renal Fabry disease.

Background: Fabry's disease (FD) is a rare, multi-organ lysosomal disease, caused by the deficiency of the enzyme α-galactosidase A, and is difficult to diagnose. Although parapelvic cysts (PC) were previously associated with FD, their prevalence and significance are unclear. Methods: The present study aimed to: (i) evaluate, by renal ultrasound, the real prevalence of PC and of their determinants in a multicentre, nationwide cohort of FD patients (n = 173, Study 1) and (ii) ascertain whether a greater accuracy of PC detection improved their identification, in FD patients from a single centre (n = 67, Study 2). In both studies, for each FD patient, an age- and renal function-matched subject was selected for comparison (1:1). Results: In Study 1, PC were detected in 28.9% of FD subjects and in only 1.1% of control subjects (P < 0.001). The presence of other renal abnormalities did not differ between the groups, nor differences exist in the main demographic and laboratory parameters between the groups. In Study 2, the greater accuracy of ultrasound increased PC prevalence from 29.8% to 43.3% in the same subjects (P < 0.05). In both studies, no correlation was detected between PC and the main demographic, clinical and biochemical parameters, including use of enzyme replacement therapy (P < 0.1, minimum value). Finally, no difference existed between FD patients with and without PC. Conclusions: The present study suggests that the presence of PC in renal patients should alert physicians to consider the diagnosis of FD, primarily in subjects with an unclear family history of renal disease and in the presence of other stigmata of the disease.

Newborn screening for lysosomal storage disorders by tandem mass spectrometry in North East Italy.

BACKGROUND: Lysosomal storage diseases (LSDs) are inborn errors of metabolism resulting from 50 different inherited disorders. The increasing availability of treatments and the importance of early intervention have stimulated newborn screening (NBS) to diagnose LSDs and permit early intervention to prevent irreversible impairment or severe disability. We present our experience screening newborns in North East Italy to identify neonates with Mucopolysaccharidosis type I (MPS I) and Pompe, Fabry, and Gaucher diseases. METHODS: Activities of acid ß-glucocerebrosidase (ABG; Gaucher), acid α-glucosidase (GAA; Pompe), acid α-galactosidase (GLA; Fabry), and acid α-L-iduronidase (IDUA; MPS-I) in dried blood spots (DBS) from all newborns during a 17-month period were determined by multiplexed tandem mass spectrometry (MS/MS) using the NeoLSD® assay system. Enzymatic activity cutoff values were determined from 3500 anonymous newborn DBS. In the screening study, samples were retested if the value was below cutoff and a second spot was requested, with referral for confirmatory testing and medical evaluation if a low value was obtained. RESULTS: From September 2015 to January 2017, 44,411 newborns were screened for the four LSDs. We recalled 40 neonates (0.09%) for collection of a second DBS. Low activity was confirmed in 20, who had confirmatory testing. Ten of 20 had pathogenic mutations: two Pompe, two Gaucher, five Fabry, and one MPS-I. The incidences of Pompe and Gaucher diseases were similar (1/22,205), with Fabry disease the most frequent (1/8882) and MPS-I the rarest (1/44411). The combined incidence of the four disorders was 1/4411 births. CONCLUSIONS: Simultaneously determining multiple enzyme activities by MS/MS, with a focus on specific biochemical markers, successfully detected newborns with LSDs. The high incidence of these disorders supports this screening program.

Systematic DNA Study for Fabry Disease in the End Stage Renal Disease Patients from a Southern Italy Area.

BACKGROUND/AIMS: Fabry disease (FD) is a lysosomal storage disorder characterized by pervasive renal involvement. However, this disease is underdiagnosed in patient with chronic kidney disease (CKD), including those with end stage renal disease (ESRD), so their investigation represents an unexploited opportunity for early diagnosis of the disease and for its identification in relatives of affected patients. METHODS: We investigated Fabry disease in a clinical and biological database including ESRD patients of unknown cause in a geographical area with 2 million residents. The study was based on state of art GLA gene sequencing and was extended to relatives of affected ESRD patients. RESULTS: Among ESRD patients qualified for enrollment into this study, a previously undiagnosed young man harboring the mutation p.I91T was identified. The study of the proband's family led to the identification of 8 additional cases. In another ESRD male patient, we identified the functional polymorphism p.D313Y. Furthermore, in 55 ESRD patients (24.2%) we found intronic polymorphisms of uncertain functional relevance in the non-coding regions of the GLA gene. CONCLUSION: A comprehensive survey of ESRD patients in a geographical area of 2 million residents identified one undiagnosed case of Fabry disease and led to the identification of 8 additional cases among his relatives. Screening protocols starting from the dialysis population and upstream extended to families of affected individuals may be an effective strategy to maximize the early identification of subjects with Fabry disease.

Mutations in the GLA Gene and LysoGb3: Is It Really Anderson-Fabry Disease?

Anderson-Fabry disease (FD) is a rare, progressive, multisystem storage disorder caused by the partial or total deficit of the lysosomal enzyme α-galactosidase A (α-Gal A). It is an X-linked, lysosomal enzymopathy due to mutations in the galactosidase alpha gene (GLA), encoding the α-Gal A. To date, more than 900 mutations in this gene have been described. In our laboratories, the study of genetic and enzymatic alterations related to FD was performed in about 17,000 subjects with a symptomatology referable to this disorder. The accumulation of globotriaosylsphingosine (LysoGb3) was determined in blood of positives. Exonic mutations in the GLA gene were detected in 471 patients (207 Probands and 264 relatives): 71.6% of mutations were associated with the classic phenotype, 19.8% were associated with the late-onset phenotype, and 8.6% of genetic variants were of unknown significance (GVUS). The accumulation of LysoGb3 was found in all male patients with a mutation responsible for classic or late-onset FD. LysoGb3 levels were consistent with the type of mutations and the symptomatology of patients. α-Gal A activity in these patients is absent or dramatically reduced. In recent years, confusion about the pathogenicity of some mutations led to an association between non-causative mutations and FD. Our study shows that the identification of FD patients is possible by associating clinical history, GLA gene analysis, α-Gal A assay, and blood accumulation of LysoGB3. In our experience, LysoGB3 can be considered a reliable marker, which is very useful to confirm the diagnosis of Fabry disease.

Desensitization of olipudase alfa-induced anaphylaxis in a child with chronic neurovisceral acid sphingomyelinase deficiency.

Olipudase alfa is indicated for the non-central nervous system manifestations of Acid sphingomyelinase deficiency (ASMD). Anaphylaxis is a very rare and life-threatening adverse reaction described for this drug. Here, we report the case of a 2-year-old boy affected by chronic neurovisceral ASMD who experienced signs of hypersensitivity reactions to olipudase alfa since the administered dose of 1 mg/kg during dose escalation and a proper anaphylactic reaction during the second administration of the target therapeutic dose of 3 mg/kg. The treatment was stopped for 15 weeks and then a 7-step desensitization protocol with the infused dose of 0.03 mg/kg was applied. Subsequent gradual dose escalation was resumed, successfully reaching the dose of 0.3 mg/kg. Moreover, biochemical, and radiological disease indexes, which were increased during treatment discontinuation, have gradually improved since the restart of treatment. However, at the second administration of the dose of 0.6 mg/kg, the patient experienced another adverse drug reaction with facial urticarial rash and bronchospasm, requiring the administration of adrenaline, methylprednisolone, and inhaled salbutamol. This case report highlights the need to customize the olipudase alfa desensitization protocol according to individual tolerance and raises the issue of achieving the established therapeutic target in the most sensitive children. Synopsis: We report a case of anaphylaxis to olipudase alfa in a child affected by chronic neurovisceral Acid sphingomyelinase deficiency (ASMD) and describe a 7-step desensitization procedure. This procedure, with the total administered dose of 0.03 mg/kg, followed by gradual dose escalation, allowed to reach the dose of 0.3 mg/kg without adverse reactions; however, at the second administration of the dose of 0.6 mg/kg our patient presented another adverse reaction suggesting the need of a different desensitization strategy.

Gaucher Disease or Acid Sphingomyelinase Deficiency? The Importance of Differential Diagnosis.

Background: Gaucher disease is a lysosomal storage disorder caused by functional glucocerebrosidase enzyme deficiency. Hepatosplenomegaly and hematological complications are found in both Gaucher disease and Acid Sphingomyelinase Deficiency, which is caused by acid sphingomyelinase dysfunction. The possible overlap in clinical presentation can cause diagnostic errors in differential diagnosis. For this reason, in patients with an initial clinical suspicion of Gaucher disease, we aimed to carry out a parallel screening of acid sphingomyelinase and glucocerebrosidase. Methods: Peripheral blood samples of 627 patients were collected, and enzymatic activity analysis was performed on both glucocerebrosidase and acid sphingomyelinase. The specific gene was studied in samples with null or reduced enzymatic activity. Specific molecular biomarkers helped to achieve the correct diagnosis. Results: In 98.7% of patients, normal values of glucocerebrosidase activity excluded Gaucher disease. In 8 of 627 patients (1.3%), the glucocerebrosidase enzymatic activity assay was below the normal range, so genetic GBA1 analysis confirmed the enzymatic defect. Three patients (0.5%) had normal glucocerebrosidase activity, so they were not affected by Gaucher disease, and showed decreased acid sphingomyelinase activity. SMPD1 gene mutations responsible for Acid Sphingomyelinase Deficiency were found. The levels of specific biomarkers found in these patients further strengthened the genetic data. Conclusions: Our results suggest that in the presence of typical signs and symptoms of Gaucher disease, Acid Sphingomyelinase Deficiency should be considered. For this reason, the presence of hepatosplenomegaly, thrombocytopenia, leukocytopenia, and anemia should alert clinicians to analyze both enzymes by a combined screening. Today, enzyme replacement therapy is available for the treatment of both pathologies; therefore, prompt diagnosis is essential for patients to start accurate treatment and to avoid diagnostic delay.

Increased glucosylsphingosine levels and Gaucher disease in GBA1-associated Parkinson's disease.

INTRODUCTION: Gaucher's disease (GD) is caused by biallelic mutations in the GBA1 gene, leading to reduced glucocerebrosidase (GCase) activity and substrate (glucosylceramide and glucosylsphingosine, GlcSph) accumulation. GBA1 variant carriers are at risk of Parkinson's disease (PD), but only those with biallelic mutations cross the threshold of GCase reduction, leading to substrate accumulation and GD. The link between GBA1 mutations, GD and PD is not fully understood. Here we aimed at reporting the results of a large PD population screening with dried blood spot tests for GD. METHODS: We measured GCase activity and GlcSph levels in 1344 PD patients with dried blood spot tests, and performed GBA1 genetic sequencing. RESULTS: While the GCase activity was reduced in GBA1-PD carriers compared to wild type PD, GlcSph was increased in GBA1-PD compared to GBA1-controls, regardless of the underlying type of GBA1 variant. 13.6 % and 0.4 % of PD patients had mono- or biallelic GBA1 mutations respectively. GCase deficiency, lipid accumulation and clinical manifestations of GD was detected in five PD patients with biallelic GBA1 mutations, of whom four had a risk combined with a GD causing variant. CONCLUSIONS: GlcSph appearing higher in PD may represent a reliable biomarker of the disease and deserves to be further investigated. This study highlights the importance of screening PD patients for possible underlying GD, which is a treatable condition that should not be missed. We diagnosed GD cases carrying a "risk" variant in one allele, which is an unprecedented finding deserving further investigation.

Identification of a novel and recurrent mutation in the SERPING1 gene in patients with hereditary angioedema.

Hereditary angioedema (HAE) due to C1 inhibitor (C1-INH) deficiency is an autosomal dominant disorder caused by mutations in SERPING1 gene. More than 200 different mutations are known, with high genetic heterogeneity and high frequency of private familial mutations. We analyzed for genetic mutations the C1-INH locus in 11 Sardinian families, revealing in seven subjects from four unrelated families the novel nonsense mutation S318X. This mutation, detected with unexpected high frequency, accounts for over a third of the here reported Sardinian families affected by HAE. The recurrence of a pathogenic mutation within the same geographical area is a unique finding, previously unreported in HAE due to C1-INH deficiency.

A classical phenotype of Anderson-Fabry disease in a female patient with intronic mutations of the GLA gene: a case report.

BACKGROUND: Fabry disease (FD) is a hereditary metabolic disorder caused by the partial or total inactivation of a lysosomal hydrolase, the enzyme α-galactosidase A (GLA). This inactivation is responsible for the storage of undegraded glycosphingolipids in the lysosomes with subsequent cellular and microvascular dysfunction. The incidence of disease is estimated at 1:40,000 in the general population, although neonatal screening initiatives have found an unexpectedly high prevalence of genetic alterations, up to 1:3,100, in newborns in Italy, and have identified a surprisingly high frequency of newborn males with genetic alterations (about 1:1,500) in Taiwan. CASE PRESENTATION: We describe the case of a 40-year-old female patient who presented with transient ischemic attack (TIA), discomfort in her hands, intolerance to cold and heat, severe angina and palpitations, chronic kidney disease. Clinical, biochemical and molecular studies were performed. CONCLUSIONS: Reported symptoms, peculiar findings in a renal biopsy - the evidence of occasional lamellar inclusions in podocytes and mesangial cells - and left ventricular (LV) hypertrophy, which are considered to be specific features of FD, as well as molecular evaluations, suggested the diagnosis of a classical form of FD.We detected four mutations in the GLA gene of the patient: -10C>T (g.1170C>T), c.370-77_-81del (g.7188-7192del5), c.640-16A>G (g.10115A>G), c.1000-22C>T (g.10956C>T). These mutations, located in promoter and intronic regulatory regions, have been observed in several patients with manifestations of FD. In our patient clinical picture showed a multisystemic involvement with early onset of symptoms, thus suggesting that these intronic mutations can be found even in patients with classical form of FD.

Hemochromatosis Mimicked Gaucher Disease: Role of Hyperferritinemia in Evaluation of a Clinical Case.

Gaucher disease is a disorder of lysosomes caused by a functional defect of the glucocerebrosidase enzyme. The disease is mainly due to mutations in the GBA1 gene, which determines the gradual storage of glucosylceramide substrate in the patient's macrophages. In this paper, we describe the case of a 38-year-old man who clinically presented with hyperferritinemia, thrombocytopenia, leukopenia, anemia and mild splenomegaly; a diagnosis of hemochromatosis was made 10 years earlier. Re-evaluation of the clinical case led to a suspicion of Gaucher disease, which was confirmed by enzymatic analysis, which was found to be below the normal range, and genetic evaluation, which identified compound heterozygosity N370S/RecNciI. We know that patients suffering from Gaucher disease can also have high ferritin levels. Even if the mechanism underlying the changes in iron metabolism is not yet elucidated, the chronic mild inflammatory state present in these patients probably causes the storage of ferritin in macrophages, resulting in hyperferritinemia. Therefore, in the presence of few typical signs and symptoms of the disease should raise an alarm bell in the clinicians, inducing clinical suspicion of Gaucher disease. Misdiagnosis and diagnostic delay in metabolic diseases could cause irreversible organ damage and delay the start of specific therapy for these patients.

miR-126-3p and miR-21-5p as Hallmarks of Bio-Positive Ageing; Correlation Analysis and Machine Learning Prediction in Young to Ultra-Centenarian Sicilian Population.

Human ageing can be characterized by a profile of circulating microRNAs (miRNAs), which are potentially predictors of biological age. They can be used as a biomarker of risk for age-related inflammatory outcomes, and senescent endothelial cells (ECs) have emerged as a possible source of circulating miRNAs. In this paper, a panel of four circulating miRNAs including miR-146a-5p, miR-126-3p, miR-21-5p, and miR-181a-5p, involved in several pathways related to inflammation, and ECs senescence that seem to be characteristic of the healthy ageing phenotype. The circulating levels of these miRNAs were determined in 78 healthy subjects aged between 22 to 111 years. Contextually, extracellular miR-146a-5p, miR-126-3p, miR-21-5p, and miR-181a-5p levels were measured in human ECs in vitro model, undergoing senescence. We found that the levels of the four miRNAs, using ex vivo and in vitro models, progressively increase with age, apart from ultra-centenarians that showed levels comparable to those measured in young individuals. Our results contribute to the development of knowledge regarding the identification of miRNAs as biomarkers of successful and unsuccessful ageing. Indeed, they might have diagnostic/prognostic relevance for age-related diseases.

Can Be miR-126-3p a Biomarker of Premature Aging? An Ex Vivo and In Vitro Study in Fabry Disease.

Fabry disease (FD) is a lysosomal storage disorder (LSD) characterized by lysosomal accumulation of glycosphingolipids in a wide variety of cytotypes, including endothelial cells (ECs). FD patients experience a significantly reduced life expectancy compared to the general population; therefore, the association with a premature aging process would be plausible. To assess this hypothesis, miR-126-3p, a senescence-associated microRNA (SA-miRNAs), was considered as an aging biomarker. The levels of miR-126-3p contained in small extracellular vesicles (sEVs), with about 130 nm of diameter, were measured in FD patients and healthy subjects divided into age classes, in vitro, in human umbilical vein endothelial cells (HUVECs) "young" and undergoing replicative senescence, through a quantitative polymerase chain reaction (qPCR) approach. We confirmed that, in vivo, circulating miR-126 levels physiologically increase with age. In vitro, miR-126 augments in HUVECs underwent replicative senescence. We observed that FD patients are characterized by higher miR-126-3p levels in sEVs, compared to age-matched healthy subjects. We also explored, in vitro, the effect on ECs of glycosphingolipids that are typically accumulated in FD patients. We observed that FD storage substances induced in HUVECs premature senescence and increased of miR-126-3p levels. This study reinforces the hypothesis that FD may aggravate the normal aging process.

Pompe disease: pathogenesis, molecular genetics and diagnosis.

Pompe disease (PD) is a rare autosomal recessive disorder caused by mutations in the GAA gene, localized on chromosome 17 and encoding for acid alpha-1,4-glucosidase (GAA). Currently, more than 560 mutations spread throughout GAA gene have been reported. GAA catalyzes the hydrolysis of α-1,4 and α-1,6-glucosidic bonds of glycogen and its deficiency leads to lysosomal storage of glycogen in several tissues, particularly in muscle. PD is a chronic and progressive pathology usually characterized by limb-girdle muscle weakness and respiratory failure. PD is classified as infantile and childhood/adult forms. PD patients exhibit a multisystemic manifestation that depends on age of onset.Early diagnosis is essential to prevent or reduce the irreversible organ damage associated with PD progression. Here, we make an overview of PD focusing on pathogenesis, clinical phenotypes, molecular genetics, diagnosis, therapies, autophagy and the role of miRNAs as potential biomarkers for PD.

Fabry disease and multiple sclerosis misdiagnosis: the role of family history and neurological signs.

Fabry disease (FD) is an X-linked inherited lysosomal storage disorder caused by α galactosidase A (α-gal A) deficiency. Central nervous system involvement and chronic white matter lesions are observed in both FD and multiple sclerosis (MS), which can confound the differential diagnosis. We analyzed the GLA gene, which encodes α-gal A, in 86 patients with clinical and neuroradiological findings consistent with MS to determine whether they had FD. We identified four women initially diagnosed with MS who had GLA mutations associated with FD. Our results indicate that family history besides neurological findings should be evaluated in patients with an uncertain diagnosis of MS. Also the involvement of organs outside the central nervous system can support the FD diagnosis.

A pilot study of circulating microRNAs as potential biomarkers of Fabry disease.

Patients suffering from Fabry disease (FD), a lysosomal storage disorder, show a broad range of symptoms and the diagnosis followed by the therapeutic decision remains a great challenge. The biomarkers available today have not proven to be useful for predicting the evolution of the disease and for assessing response to therapy in many patients. Here, we used high-throughput microRNA profiling methodology to identify a specific circulating microRNA profile in FD patients. We discovered a pattern of 10 microRNAs able to identify FD patients when compared to healthy controls. Notably, two of these: the miR199a-5p and the miR-126-3p are able to discriminate FDs from the control subjects with left ventricular hypertrophy, a frequent but non-specific FD symptom. These same microRNAs are also sensitive to enzyme replacement therapy showing variation in the subjects under treatment. Furthermore, two other microRNAs of the profile, the miR-423-5p and the miR-451a, seem useful to highlight cardiac involvement in FD patients. A literature and database search revealed that miR-199a-5p, miR-126-3p, miR-423-5p and miR-451a are known to be linked to pathological states that occur during the FD development. In particular, miR-199a-5p, and miR-126-3p are involved in endothelial dysfunction and miR-423-5p and miR-451a in myocardial remodeling. In conclusion, in this study we identified a common plasma microRNA profile in FD patients, useful not only for the correct classification of Fabry patients regardless of sex and age, but also to evaluate the response to therapy. Furthermore, our observations suggest that some microRNAs of this profile demonstrate prognostic qualities.