Daniela Antuzzi

Prevalence of Fabry Disease in Female Patients With Late-Onset Hypertrophic Cardiomyopathy

Background—Fabry disease (FD) has been recognized as the cause of left ventricular hypertrophy in 6% of men with late-onset hypertrophic cardiomyopathy (HCM). Although FD is considered a recessive X-linked disorder, affected women are increasingly reported. The aim of our study was to determine the prevalence of FD in female patients with HCM. Methods and Results—Thirty-four consecutive women (mean age, 50±13.6 years) who received an ECG and echocardiographic diagnosis of HCM were submitted to an invasive cardiac study that included a biventricular endomyocardial biopsy. Tissue samples were analyzed for histology and electron microscopy. Peripheral blood activity of &agr;-galactosidase (&agr;-Gal) A was assessed in all patients. None of them had a family history of FD. Histology and electron microscopy showed in 4 patients (12%; mean age, 51.5±3.9 years) the presence of cell vacuoles characterized by the accumulation of glycolipid material organized in concentric lamellar structures, diagnostic for FD. In the remaining patients, histology was consistent with HCM. In all the female carriers, the heart was the only organ clinically involved in the disease, showing concentric hypertrophy in 2 patients, asymmetric hypertrophy in 1, and apical hypertrophy in 1. The &agr;-Gal A enzymatic activity was 44±14% of control values. Genetic analysis showed the presence of &agr;-Gal A gene mutation in all 4 cases. Conclusions—FD may account for up to 12% of females with late-onset HCM. Those heterozygous for FD with left ventricular hypertrophy are potential candidates for enzyme enhancement/replacement therapy.

GM1 gangliosidosis and Morquio B disease: an update on genetic alterations and clinical findings

GM1 gangliosidosis and Morquio B syndrome, both arising from beta-galactosidase (GLB1) deficiency, are very rare lysosomal storage diseases with an incidence of about 1:100,000-1:200,000 live births worldwide. Here we report the beta-galactosidase gene (GLB1) mutation analysis of 21 unrelated GM1 gangliosidosis patients, and of 4 Morquio B patients, of whom two are brothers. Clinical features of the patients were collected and compared with those in literature. In silico analyses were performed by standard alignments tools and by an improved version of GLB1 three-dimensional models. The analysed cohort includes remarkable cases. One patient with GM1 gangliosidosis had a triple X syndrome. One patient with juvenile GM1 gangliosidosis was homozygous for a mutation previously identified in Morquio type B. A patient with infantile GM1 gangliosidosis carried a complex GLB1 allele harbouring two genetic variants leading to p.R68W and p.R109W amino acid changes, in trans with the known p.R148C mutation. Molecular analysis showed 27 mutations, 9 of which are new: 5 missense, 3 microdeletions and a nonsense mutation. We also identified four new genetic variants with a predicted polymorphic nature that was further investigated by in silico analyses. Three-dimensional structural analysis of GLB1 homology models including the new missense mutations and the p.R68W and p.R109W amino acid changes showed that all the amino acid replacements affected the resulting protein structures in different ways, from changes in polarity to folding alterations. Genetic and clinical associations led us to undertake a critical review of the classifications of late-onset GM1 gangliosidosis and Morquio B disease.

IDUA mutational profiling of a cohort of 102 European patients with mucopolysaccharidosis type I: identification and characterization of 35 novel α-L-iduronidase (IDUA) alleles

Mutational analysis of the IDUA gene was performed in a cohort of 102 European patients with mucopolysaccharidosis type I. A total of 54 distinct mutant IDUA alleles were identified, 34 of which were novel including 12 missense mutations, 2 nonsense mutations, 12 splicing mutations, 5 micro‐deletions, 1 micro‐duplication 1 translational initiation site mutation, and 1 ‘no‐stop’ change (p.X654RextX62). Evidence for the pathological significance of all novel mutations identified was sought by means of a range of methodological approaches, including the assessment of evolutionary conservation, RT‐PCR/in vitro splicing analysis, MutPred analysis and visual inspection of the 3D‐model of the IDUA protein. Taken together, these data not only demonstrate the remarkable mutational heterogeneity characterizing type 1 mucopolysaccharidosis but also illustrate our increasing ability to make deductions pertaining to the genotype‐phenotype relationship in disorders manifesting a high degree of allelic heterogeneity.

Angiokeratoma: Decision-making aid for the diagnosis of Fabry disease

Isolated angiokeratomas are common benign cutaneous lesions, generally deemed unworthy of further investigation. In contrast, diffuse angiokeratomas should alert the physician to a possible diagnosis of Fabry disease, a rare X‐linked lysosomal storage disorder, characterized by α‐galactosidase deficiency. Glycosphingolipids accumulate in cells throughout the body resulting in progressive multi‐organ failure. Difficulties are encountered when trying to interpret the significance of angiokeratomas because they may also occur in other lysosomal storage disorders and rarely in an isolated manner in Fabry disease. We present an algorithm for the classification of angiokeratomas which might prove useful for the diagnosis and management of Fabry disease. Assessment of the clinical features and location of the lesions, personal and family history, skin biopsy, dermoscopy and electron microscopy imaging are sequential steps in the diagnostic process. Assessing the deficiency of α‐galactosidase enzyme activity is essential to confirm the diagnosis in males, while mutation analysis is always needed in females. Potentially this algorithm can change the current approach to patients when Fabry disease is suspected, thus improving the diagnostic strategy and management of this disorder. It remains to be decided whether the use of an algorithm might reduce the number of genetic consultations. As evidence has shown the efficacy of enzyme replacement therapy in halting progression of the disease before the onset of irreversible organ damage, it is advisable to aim at an early diagnosis in order to achieve timely initiation of effective treatment with benefits for patients and appropriate use of medical resources.

Functional assessment of Aδ and C fibers in patients with Fabry's disease

The pathophysiology of neuropathic pain in Fabrys disease (FD) is still largely unknown. Seven FD patients were studied by laser evoked potentials (LEPs) to assess the function of the Aδ and C fibers. Laser pulses were delivered on the skin of the hand and perioral region at painful intensity to record LEPs related to Aδ‐fiber inputs and at nonpainful intensity to obtain LEPs related to C‐fiber inputs. When the perioral region was stimulated, a vertex positive component was recorded with a mean latency of 260.3 ms and 376 ms after Aδ‐ and C‐fiber stimulation, respectively. The mean Aδ‐LEP amplitude was significantly lower in FD patients (N1/P1 mean values were 2.8 μV and 4.5 μV after hand and face stimulation, respectively, compared to 4 μV and 8.9 μV for controls; N2/P2 mean values were 8.2 μV and 11.1 μV after hand and face stimulation, respectively, and 16.7 μV and 22.3 μV in controls). Unlike the healthy subjects, 6 FD patients, suffering from neuropathic pain, showed a late positive potential related to C‐fiber function (mean latency, 377.1 ms) also after facial stimulation at painful intensity, suggesting a relative overflow of C‐fiber input, which may be relevant in the pathophysiology of pain in this disease. Muscle Nerve, 2004

Fabry disease: polymorphic haplotypes and a novel missense mutation in the GLA gene

Ferri L, Guido C, la Marca G, Malvagia S, Cavicchi C, Fiumara A, Barone R, Parini R, Antuzzi D, Feliciani C, Zampetti A, Manna R, Giglio S, Della Valle CM, Wu X, Valenzano KJ, Benjamin ER, Donati MA, Guerrini R, Genuardi M, Morrone A. Fabry disease: polymorphic haplotypes and a novel missense mutation in the GLA gene.

Cardiac and skeletal myopathy in Fabry disease: a clinicopathologic correlative study

Summary Skeletal muscle disturbances are commonly reported in patients with Fabry disease. Whether they derive from cardiac dysfunction or direct muscle involvement is still unclear. Clinical, noninvasive, and invasive cardiac and muscle studies, including an endomyocardial and muscle biopsy, were obtained in 12 patients (mean age, 42.1 ± 12.6 years; range, 24-58 years) with Fabry disease. In the youngest patients (group A, 4 men aged <35 years), results of cardiac and skeletal noninvasive studies were normal, except for reduced velocities in tissue Doppler imaging. Histologic examination indicated that muscle myocytes were unaffected, whereas muscle vessels showed the presence of mild glycosphingolipid accumulation in endothelial and smooth muscle cells. In the heart, cardiomyocytes and endothelial and smooth muscle cells of intramural cardiac vessels were involved by the disease. The oldest patients (group B, 6 men and 2 women aged >35 years) showed ultrasound muscle disarray and electromyography signs of myopathy, increased left ventricular mass, and normal cardiac function. Histologic examination showed that muscle myocytes contained mild glycosphingolipid accumulation compared with severe engulfment of cardiomyocytes. Moreover, similar infiltration of myocardial and muscle intramural vessels, causing lumen narrowing and fibrofatty tissue replacement, was observed. Direct muscle involvement occurs in patients with Fabry disease. It is milder and delayed compared with that in the heart. The difference in organ function and the need of residual α-galactosidase A activity are the likely causes.

Inhibition of cardiomyocyte lysosomal activity in hydroxychloroquine cardiomyopathy

hydroxychloroquine cardiomyopathy Andrea Frustaci ⁎, Emanuela Morgante , Daniela Antuzzi , Matteo Antonio Russo , Cristina Chimenti a,e a Department of Cardiology, La Sapienza University, Italy b National Institute of Infectious Diseases L. Spallanzani, Italy c Department of Pathology and Experimental Medicine La Sapienza University, Italy d Department of Pediatrics, Catholic University, Italy e IRCCS San Raffaele La Pisana, Rome, Italy

Two novel mutations in the gene for human α-mannosidase that cause α-mannosidosis

Summary: Mutation analysis performed on two Italian patients with α-mannosidosis allowed the identification of two new mutations, IVS20−2A>G and 322–323insA. The patients were both homozygous for these mutations. The first mutation causes skipping of exon 21, whereas the second causes a frameshift introducing a stop codon at position 160 of the amino acid sequence.

Serum interleukin-18 in children with Henoch-Schonlein purpura: a promising marker of disease activity?

Henoch-Schönlein purpura (HSp) is the most common systemic vasculitis of childhood with typical skin involvement and concurrent signs involving joints, gastrointestinal tract, and kidney. HSp pathogenesis is still far from being completely understood, though a knotty cytokine complex is believed to contribute to its intimate processes. The aim of our evaluation is to establish the relationship between serum levels of interleukin (IL)-18 and disease outcome and establish its feasibility to provide a marker of disease activity or even a prognostic tool in clinical practice. We examined clinical/laboratory variables and serum IL-18 in 17 children hospitalized during a year for HSp, diagnosed by EULAR/PRINTO/PRES criteria; the same patients were re-evaluated after 6 months. All results were compared with 25 age-matched healthy controls. IL-12 and IL-6 were also evaluated in a cohort of the same patients and compared with controls. General and clinical variables (sex, edema of the extremities, gastrointestinal or renal complications, relapses and renal involvement at 6 months) had no relationship with cytokine levels. Serum IL-18 and IL-6 levels were found significantly increased at diagnosis in HSp patients when compared with healthy controls. After 6 months, serum IL-18 and IL-12 levels were significantly decreased in patients, while IL-12 and IL-6 levels were significantly increased compared to healthy controls. Though preliminary and expecting further confirmation on a larger sample, our data support the conclusion that serum IL-18 levels reflect HSp activity.