Anna Modoni

Screening of ARHSP-TCC patients expands the spectrum of SPG11 mutations and includes a large scale gene deletion.

Autosomal recessive spastic paraplegia with thinning of corpus callosum (ARHSP‐TCC) is a complex form of HSP initially described in Japan but subsequently reported to have a worldwide distribution with a particular high frequency in multiple families from the Mediterranean basin. We recently showed that ARHSP‐TCC is commonly associated with mutations in SPG11/KIAA1840 on chromosome 15q. We have now screened a collection of new patients mainly originating from Italy and Brazil, in order to further ascertain the spectrum of mutations in SPG11, enlarge the ethnic origin of SPG11 patients, determine the relative frequency at the level of single Countries (i.e., Italy), and establish whether there is one or more common mutation. In 25 index cases we identified 32 mutations; 22 are novel, including 9 nonsense, 3 small deletions, 4 insertions, 1 in/del, 1 small duplication, 1 missense, 2 splice‐site, and for the first time a large genomic rearrangement. This brings the total number of SPG11 mutated patients in the SPATAX collection to 111 cases in 44 families and in 17 isolated cases, from 16 Countries, all assessed using homogeneous clinical criteria. While expanding the spectrum of mutations in SPG11, this larger series also corroborated the notion that even within apparently homogeneous population a molecular diagnosis cannot be achieved without full gene sequencing.

Cognitive impairment in myotonic dystrophy type 1 (DM1) : A longitudinal follow-up study

ObjectiveTo characterize the progression of the cognitive involvement in patients affected by myotonic dystrophy type 1 (DM1) by a longitudinal neuropsychological follow-up study.MethodsIn a previous study we documented an ageing-related decline of frontal and temporal cognitive functions in juvenile/adult forms of DM1, irrespectively of the n(CTG) in leukocytes and the severity of muscle weakness. Here we present the results of a neuropsychological follow-up study performed in 34 out of 70 DM1 patients previously studied. Patients were divided into four groups according to their genotype (E1:50-150; E2:150-500; E3:500-1000; E4: >1000 CTG). The neuropsychological test battery included MMSE, memory, linguistic, level, praxis, attentional and frontal-executive tasks. Statistical analysis was performed by One way MANOVA with repeated measures analysis and by Wilcoxon match paired test.ResultsThe whole group of patients showed a significant deterioration in linguistic functions, together with a tendency towards decline in executive abilities, confirming a predominant involvement of cognitive functions subserved by fronto-temporal areas. We found no significant correlation between the progression of cognitive decline and the n(CTG) in leukocytes. Moreover, we observed that patients belonging to E2 group, with the highest mean age, got scores lower than E3 patients, with particular regard both to linguistic and executive tasks.ConclusionsThese data support our previous hypothesis that the cognitive damage is confined to frontotemporal functions in adult DM1 patients, with a tendency towards a decline with aging.

An Italian family with inclusion-body myopathy and frontotemporal dementia due to mutation in the VCP gene

Mutations of the valosin‐containing protein gene (VCP) are responsible for autosomal‐dominant hereditary inclusion‐body myopathy associated with frontotemporal dementia and Pagets disease of bone. We identified the p.R155C missense mutation in the VCP gene segregating in an Italian family with three affected siblings, two of whom had a progressive myopathy associated with dementia, whereas one exhibited a progressive myopathy and preclinical signs of Pagets disease of bone. Our study demonstrates that VCP mutations are found in patients of Italian background and may lead to a variable clinical phenotype even within the same kinship. Muscle Nerve, 2007

A new mtDNA mutation associated with a progressive encephalopathy and cytochrome c oxidase deficiency

Article abstract The authors describe a novel pathogenic G5540A transition in the mitochondrial transfer RNA (tRNA)Trp gene of a sporadic encephalomyopathy characterized by spinocerebellar ataxia. Clinical features also included neurosensorial deafness, peripheral neuropathy, and dementia. Biochemistry revealed a severe reduction of cytochrome c oxidase (COX) activity. Single-fiber PCR demonstrated higher levels of mutant genomes in COX-negative ragged red fibers than in normal fibers. These findings confirm that COX is more susceptible than other respiratory chain complexes to mutations in the mitochondrial tRNATrp gene.

Risk of arrhythmias in myotonic dystrophy: trial design of the RAMYD study.

Objective Myotonic dystrophy type 1 (DM1) is the most frequent muscular dystrophy in adults. DM1 is a multisystem disorder also affecting the heart with an increased incidence of sudden death, which has been explained with the common impairment of the conduction system often requiring pacemaker implantation; however, the occurrence of sudden death despite pacemaker implantation and the observation of major ventricular arrhythmias generated the hypothesis that ventricular arrhythmias may play a causal role as well. The aim of the study was to assess the 2-year cumulative incidence and the value of noninvasive and invasive findings as predictive factors for sudden death, resuscitated cardiac arrest, ventricular fibrillation, sustained ventricular tachycardia and severe sinus dysfunction or high-degree atrioventricular block. Methods/design More than 500 DM1 patients will be evaluated at baseline with a clinical interview, 12-lead ECG, 24-h ECG and echocardiogram. Conventional and nonconventional indications to electrophysiological study, pacemaker, implantable cardioverter defibrillator or loop recorder implantation have been developed. In the case of an indication to electrophysiological study, pacemaker, implantable cardioverter defibrillator or loop recorder implant at baseline or at follow-up, the patient will be referred for the procedure. At the end of 2-year follow-up, all candidate prognostic factors will be tested for their association with the endpoints. Trial registration: ClinicalTrials.gov ID NCT00127582. Conclusion The available evidence supports the hypothesis that both bradyarrhythmias and tachyarrhythmias may cause sudden death in DM1, but the course of cardiac disease in DM1 is still unclear. We expect that this large, prospective, multicenter study will provide evidence to improve diagnostic and therapeutic strategies in DM1.

Chronic autoimmune autonomic neuropathy responsive to immunosuppressive therapy

Autoimmune autonomic neuropathy refers to a group of autoimmune disorders characterized by the failure of both sympathetic and parasympathetic systems,1 related to the presence of autoantibodies against neuronal ganglionic acetylcholine (AChR) receptors.2 These antibodies are detectable in the serum of about 30% of patients with paraneoplastic-acquired autoimmune autonomic neuropathy and in 50% of patients with idiopathic subacute autoimmune autonomic neuropathy.3 We describe a 59-year-old woman who presented 6 months after the gradual development of severe dysautonomia, characterized by recurrent orthostatic syncope, dry mouth, early satiety, constipation, and urinary retention. Family history was negative and she denied any viral illness preceding the onset of the above symptoms. The results of physical examination showed her blood pressure to be 115/70 mm Hg in a supine position, but fell to 80/50 mm Hg in a sitting position; the patient was unable to stand upright for more than a few seconds because of a fainting sensation. Pupillary responses to light were torpid; however, the remaining neurologic examination was normal. Routine blood tests, including glucose determination, were normal. X-ray gastrointestinal transit evaluation after barium ingestion documented markedly delayed gut motility …

Alternative splicing alterations of Ca2+ handling genes are associated with Ca2+ signal dysregulation in myotonic dystrophy type 1 (DM1) and type 2 (DM2) myotubes.

The pathogenesis of myotonic dystrophy type 1 (DM1) and type 2 (DM2) has been related to the aberrant splicing of several genes, including those encoding for ryanodine receptor 1 (RYR1), sarcoplasmatic/endoplasmatic Ca2+‐ATPase (SERCA) and α1S subunit of voltage‐gated Ca2+ channels (Cav1.1). The aim of this study is to determine whether alterations of these genes are associated with changes in the regulation of intracellular Ca2+ homeostasis and signalling.

Alternative splicing alterations of Ca(2+) handling genes are associated with Ca(2+) signal dysregulation in DM1 and DM2 myotubes

The pathogenesis of myotonic dystrophy type 1 (DM1) and type 2 (DM2) has been related to the aberrant splicing of several genes, including those encoding for ryanodine receptor 1 (RYR1), sarcoplasmatic/endoplasmatic Ca2+‐ATPase (SERCA) and α1S subunit of voltage‐gated Ca2+ channels (Cav1.1). The aim of this study is to determine whether alterations of these genes are associated with changes in the regulation of intracellular Ca2+ homeostasis and signalling.

A novel KIF5A/SPG10 mutation in spastic paraplegia associated with axonal neuropathy.

JO N 2 84 0 5 % of the AD-HSP patients harbor mutations in less common genes (NIPA1/SPG6, KIF5A/SPG10, REEP1/SPG31, BSCL2/SPG17, ZFYVE27/SPG33, KIAA0196/SPG8, HSPD1/SPG13) with possible variations in frequency in different populations [5]. The remaining cases harbor mutations in as yet unknown genes. To determine the relative incidence of less common AD-HSP etiologies, we systematically screened for mutations in a cohort of 25 patients with documented AD-HSP and 50 apparently sporadic cases without prior linkage data information and in whom mutations or rearrangements in SPG4 had been excluded by reported methodologies [2]. SPG3A mutations had also been ruled out in 9 cases where onset was < 10 years. After obtaining written informed consent, we purified genomic DNA from peripheral blood using standard procedures. PCR amplification of exons and flanking intronic sequences using specific primer pairs was followed by dHPLC and direct sequencing of amplified fragments to analyze the coding regions of NIPA1/SPG6, KIF5A/SPG10, REEP1/SPG31, BSCL2/SPG17, HSPD1/SPG13. We identified a novel missense mutation in KIF5A/SPG10 in an Italian family (Fig. 1A). The proposita (II:01) was a 39 year-old woman. Her spastic gait was initially identified at the age of 30 years and has Alessandra Tessa Gabriella Silvestri Maria Fulvia de Leva Anna Modoni Paola S. Denora Marcella Masciullo M. Teresa Dotti Carlo Casali Mariarosa A. B. Melone Antonio Federico Alessandro Filla Filippo M. Santorelli

Single-fiber PCR in MELAS3243 patients: Correlations between intratissue distribution and phenotypic expression of the mtDNAA3243G genotype

We performed morphological, biochemical, and genetic studies, including single-fiber PCR (sf PCR), on muscle biopsies obtained from a mother and daughter with MELAS syndrome due to the A3243G transition of mitochondrial DNA (mtDNA). The severity of muscle involvement appeared quite distinct, in spite of the fact that both patients segregated similar mutant mtDNA levels on total muscle DNA. The daughter did not show any clinical muscle involvement: muscle biopsy revealed many ragged red fibers (RRFs) mostly positive for cytochrome-c oxidase (COX) activity. In contrast, her mother had developed a generalized myopathy without progressive external ophthalmoplegia (PEO), morphologically characterized by many COX-negative RRFs. Single-muscle fiber PCR demonstrated in both patients significantly higher percentages of wild-type mtDNA in normal fibers (daughter: 23.25 +/- 15.22; mother: 43.13 +/- 26.11) than in COX-positive RRFs (daughter: 11.25 +/- 5.22, P < 0.005; mother: 9.12 +/- 5.9, P < 0.001) and in COX-negative RRFs (daughter: 8.9 +/- 4.2, P < 0.001 mother: 4.8 +/- 2.8, P < 0.001). Wild-type mtDNA levels resulted higher also in COX-positive vs. COX-negative RRFs (daughter: P < 0.05; mother: P < 0.001). Our data confirm a direct correlation between A3243G levels and impairment of COX function at the single-muscle fiber level. Moreover, the evidence of a clinical myopathy in the patient with higher amounts of COX-negative RRFs bolsters the concept that a differential distribution of mutant mtDNAs at the cellular level may have effects on the clinical involvement of individual tissues. However, the occurrence of a similar morphological and biochemical muscle phenotype also in PEO(3243) patients suggests that other genetic factors involved in the interaction between mitochondrial and nuclear DNA, rather than the stochastic distribution of mtDNA genomes during embryogenesis, are primarily implicated in determining the various clinical expressions of the A3243G of mtDNA.