CLCN1 Molecular Characterization in 19 South-Italian Patients With Dominant and Recessive Type of Myotonia Congenita.

Myotonia congenita is a genetic disease characterized by impaired muscle relaxation after forceful contraction (myotonia). It is caused by mutations in the CLCN1 gene, encoding the voltage-gated chloride channel of skeletal muscle, ClC-1. According to the pattern of inheritance, two distinct clinical forms have been described, Thomsen disease, inherited as an autosomal dominant trait and Becker disease inherited as an autosomal recessive trait. We report genetic and clinical data concerning 19 patients-13 familial and six isolated cases-all but one originating from the Campania Region, in southern Italy. Twelve patients (63.2%) present Becker type myotonia and 7 (36.8%) Thomsen type. Sex ratio M:F in Becker type is 6:6, while in Thomsen myotonia 4:3. The age of onset of the disease ranged from 2 to 15 years in Becker patients, and from 4 to 20 years in Thomsen. Overall 18 mutations were identified, 10 located in the coding part of the gene (exons 1, 3, 4, 5, 7, 8, 13, 15, 21, 22), and four in the intron part (introns 1, 2, 10, 18). All the exon mutations but two were missense mutations. Some of them, such as c.2551 G > A, c.817G > A and c.86A > C recurred more frequently. About 70% of mutations was inherited with an autosomal recessive pattern, two (c.86A and c.817G>A) with both mechanisms. Three novel mutations were identified, never described in the literature: p.Gly276Ser, p.Phe486Ser, and p.Gln812*, associated with Becker phenotype. Furthermore, we identified three CLCN1 mutations-c.86A>C + c.2551G > A, c.313C > T + c.501C > G and 899G > A + c.2284+5C > T, two of them inherited in cis on the same allele, in three unrelated families. The concomitant occurrence of both clinical pictures-Thomsen and Becker-was observed in one family. Intra-familial phenotypic variability was observed in two families, one with Becker phenotype, and one with Thomsen disease. In the latter an incomplete penetrance was hypothesized.

The variability of SMCHD1 gene in FSHD patients: evidence of new mutations.

In this study, we investigated the sequence of (Structural Maintenance of Chromosomes flexible Hinge Domain containing 1) SMCHD1 gene in a cohort of clinically defined FSHD (facioscapulohumeral muscular dystrophy) patients in order to assess the distribution of SMCHD1 variants, considering the D4Z4 fragment size in terms of repeated units (RUs; short fragment: 1-7 RU, borderline: 8-10RU and normal fragment: >11RU). The analysis of SMCHD1 revealed the presence of 82 variants scattered throughout the introns, exons and 3'untranslated region (3'UTR) of the gene. Among them, 64 were classified as benign polymorphisms and 6 as VUS (variants of uncertain significance). Interestingly, seven pathogenic/likely pathogenic variants were identified in patients carrying a borderline or normal D4Z4 fragment size, namely c.182_183dupGT (p.Q62Vfs*48), c.2129dupC (p.A711Cfs*11), c.3469G>T (p.G1157*), c.5150_5151delAA (p.K1717Rfs*16) and c.1131+2_1131+5delTAAG, c.3010A>T (p.K1004*), c.853G>C (p.G285R). All of them were predicted to disrupt the structure and conformation of SMCHD1, resulting in the loss of GHKL-ATPase and SMC hinge essential domains. These results are consistent with the FSHD symptomatology and the Clinical Severity Score (CSS) of patients. In addition, five variants (c.*1376A>C, rs7238459; c.*1579G>A, rs559994; c.*1397A>G, rs150573037; c.*1631C>T, rs193227855; c.*1889G>C, rs149259359) were identified in the 3'UTR region of SMCHD1, suggesting a possible miRNA-dependent regulatory effect on FSHD-related pathways. The present study highlights the clinical utility of next-generation sequencing (NGS) platforms for the molecular diagnosis of FSHD and the importance of integrating molecular findings and clinical data in order to improve the accuracy of genotype-phenotype correlations.

Are there real benefits to implanting cardiac devices in patients with end-stage dilated dystrophinopathic cardiomyopathy? Review of literature and personal results.

Cardiomyopathy associated with dystrophinopathies - Duchenne muscular Dystrophy (DMD), Becker muscular dystrophy (BMD), X-linked dilated cardiomyopathy (XL-CM) and cardiomyopathy of Duchenne/Becker (DMD/BMD carriers - is an almost constant manifestation of these neuromuscular disorders and contribute significantly to their morbidity and mortality. Dystrophinopathic cardiomyopathy is the result of the dystrophin protein deficiency at the myocardium level, parallel to that occurring at the skeletal muscle level. Typically, cardiomyopathy begins as a "presymptomatic" stage in the first decade of life and evolves in a stepwise manner toward an end-stage dilated cardiomyopathy. Nearly complete replacement of the myocardium by fibrous and fatty connective tissue results in an irreversible cardiac failure, characterized by a further reduction of ejection fraction (EF < 30%) and frequent episodes of acute heart failure (HF). The picture of a severe dilated cardiomyopathy with intractable heart failure is typical of dystrophinopathies. Despite an appropriate pharmacological treatment, this condition is irreversible because of the extensive loss of myocites. Heart transplantation is the only curative therapy for patients with end-stage heart failure, who remain symptomatic despite an optimal medical therapy. However there is a reluctance to perform heart transplantation (HT) in these patients due to the scarcity of donors and the concerns that the accompanying myopathy will limit the benefits obtained through this therapeutic option. Therefore the only possibility to ameliorate clinical symptoms, prevent fatal arrhythmias and cardiac death in dystrophinopathic patients could be the implantation of intracardiac device (ICD) or resynchronizing devices with defibrillator (CRT-D). This overview reports the personal series of patients affected by DMD and BMD and DMD carriers who received ICD or CRT-D system, describe the clinical outcomes so far published and discuss pro and cons in the use of such devices.

Cardiac diseases as a predictor warning of hereditary muscle diseases. The case of laminopathies.

Mutations in the LMNA gene are associated with a wide spectrum of disease phenotypes, ranging from neuromuscular, cardiac and metabolic disorders to premature aging syndromes. Skeletal muscle involvement may present with different phenotypes: limb-girdle muscular dystrophy type 1B or LMNA-related dystrophy; autosomal dominant Emery-Dreifuss muscular dystrophy; and a congenital form of muscular dystrophy, frequently associated with early onset of arrhythmias. Heart involvement may occur as part of the muscle involvement or independently, regardless of the presence of the myopathy. Notably conduction defects and dilated cardiomyopathy may exist without a muscle disease. This paper will focus on cardiac diseases presenting as the first manifestation of skeletal muscle hereditary disorders such as laminopathies, inspired by two large families with cardiovascular problems long followed by conventional cardiologists who did not suspect a genetic muscle disorder underlying these events. Furthermore it underlines the need for a multidisciplinary approach in these disorders and how the figure of the cardio-myo-geneticist may play a key role in facilitating the diagnostic process, and addressing the adoption of appropriate prevention measures.

The mortality effects of changing public funding for home health care: An empirical analysis of Medicare home health care in the United States.

In light of population aging, it is important to understand whether limiting public in-kind transfers to the elderly affects elderly mortality. I focus on home health care-a popular in-kind transfer-and I exploit variation in the Medicare home health care reimbursement that arose in 1997 in the United States to study whether cuts to government coverage of home health care affected elderly mortality. Under the identifying assumptions of the DID model, I find that the cuts affected total mortality for some men but not women, suggesting that changes in home health care can affect elderly mortality and differences in mortality between men and women. For men aged between 65 and 74, the Interim Payment System was associated with an increase in mortality equal to 0.6%, an effect in absolute value comparable to the mortality response to a one percentage point change in unemployment rates and within the range of other estimates of the impact of health insurance on elderly mortality.

Therapeutic approach with Ataluren in Duchenne symptomatic carriers with nonsense mutations in dystrophin gene. Results of a 9-month follow-up in a case report.

Duchenne muscular Dystrophy (DMD) is a X-linked degenerative disorder affecting skeletal muscles and myocardium caused by mutations in the dystrophin gene, mainly deletions and duplications. Point-mutations account for 13% and stop codon mutations are even more unfrequent. A drug treatment for patients with DMD caused by stop codon gene mutations and still ambulant, has become recently available, based on the clear demonstration of its efficacy in slowing the course of the disease. The drug is able to read through the stop codon; furthermore it has the advantage of an oral administration and a better patient's compliance. We report a case of a still ambulant 27 year-old DMD symptomatic carrier with a stop-codon mutation in exon 53 (c.7792C > T; p.Gln2598Stop), who started the treatment with Ataluren at a dosage of 2,250 mg/die, reporting a prompt subjective improvement in muscle strength. Unfortunately two months after, the patient discontinued taking the drug for a traumatic femur fracture requiring surgical repair and prolonged rehabilitation. With the resumption of the drug intake in February 2018, the patient reported almost immediately an improvement in motor skills, including the possibility of recovering walking, first with support and then unsupported. These results seem even more encouraging, as Duchenne patients hardly recover the ability to walk following a fracture at this age and extend the possibility to treat with ataluren also the symptomatic Duchenne carriers who have nonsense dystrophin gene mutations. Furthermore the case here reported supports the concept that symptomatic DMD female carriers must enjoy the same therapeutic opportunities offered to males.

Management of cardiac involvement in muscular dystrophies: paediatric versus adult forms.

Muscular dystrophies are a group of genetic disorders characterized by muscle degeneration and consequent substitution by fat and fibrous tissue. Cardiac involvement is an almost constant feature in a great part of these diseases, as both primary myocardial involvement and secondary involvement due to respiratory insufficiency, pulmonary hypertension or reduced mobility. Primary myocardial involvement usually begins more precociously compared to the secondary involvement. In fact the first signs of cardiomyopathy can be observed in the first decade of life in muscular dystrophies with childhood onset and later in adult form of muscular dystrophies as myotonic dystrophy type 1. At least an annual cardiac follow-up is recommended in these patients including clinical and instrumental examination (ECG, 24h Holter monitoring, ECHO), to detect cardiac involvement. A more frequent monitoring may be required according to the type of cardiomyopathy and the patient's needs. In this short review practical guide-lines are shown for physicians routinely involved in the management of these patients.

Quantifying randomness in real networks.

Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks--the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain--and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs.

Clinical features of patients with dystrophinopathy sharing the 45-55 exon deletion of DMD gene.

Becker muscular dystrophy (BMD) was first described in 1953 by Emile Becker as a benign variant of Duchenne muscular Dystrophy (DMD). Compared with DMD, BMD is clinically more heterogeneous, with initial presentation in the teenage years and loss of ambulation beyond the age of 16 and a wide spectrum of clinical presentations, ranging from only myalgias and muscle cramps to exercise intolerance and myoglobinuria, asymptomatic elevation of serum creatin-kinase, or mild limb-girdle weakness and quadriceps myopathy. About 50% of patients become symptomatic by the age of 10 and the most part by the age of 20 years. However few patients can be free of symptoms till their fifties and cases of late-onset Becker Muscular Dystrophy have also been described. In this report we describe the clinical features of patients with dystrophinopathy sharing a deletion of exons 45-55, occasionally or retrospectively diagnosed. These data are important for both the prognostic aspects of children presenting this dystrophin gene mutation, and for the genetic counseling in these families (reassuring them on the benign course of the disease), and last but not least to keep in mind a diagnosis of BMD in asymptomatic adults with mild hyperckemia.

Macro-economic conditions and infant health: a changing relationship for black and white infants in the United States.

We study whether the relationship between the state unemployment rate at the time of conception and infant health, infant mortality and maternal characteristics in the United States has changed over the years 1980-2004. We use microdata on births and deaths for years 1980-2004 and find that the relationship between the state unemployment rate at the time of conception and infant mortality and birthweight changes over time and is stronger for blacks than whites. For years 1980-1989 increases in the state unemployment rate are associated with a decline in infant mortality among blacks, an effect driven by mortality from gestational development and birth weight, and complications of placenta while in utero. In contrast, state economic conditions are unrelated to black infant mortality in years 1990-2004 and white infant mortality in any period, although effects vary by cause of death. We explore potential mechanisms for our findings and, including mothers younger than 18 in the analysis, uncover evidence of age-related maternal selection in response to the business cycle. In particular, in years 1980-1989 an increase in the unemployment rate at the time of conception is associated with fewer babies born to young mothers. The magnitude and direction of the relationship between business cycles and infant mortality differs by race and period. Age-related selection into motherhood in response to the business cycle is a possible explanation for this changing relationship.