{"title":"Current understanding and treatment of cardiac and skeletal muscle pathology in laminin-α2 chain-deficient congenital muscular dystrophy","authors":"Q. Nguyen, K. Lim, T. Yokota","doi":"10.2147/TACG.S187481","DOIUrl":"https://doi.org/10.2147/TACG.S187481","url":null,"abstract":"Abstract Congenital muscular dystrophy (CMD) is a class of severe early-onset muscular dystrophies affecting skeletal/cardiac muscles as well as the central nervous system (CNS). Laminin-α2 chain-deficient congenital muscular dystrophy (LAMA2 MD), also known as merosin-deficient congenital muscular dystrophy type 1A (MDC1A), is an autosomal recessive CMD characterized by severe muscle weakness and degeneration apparent at birth or in the first 6 months of life. LAMA2 MD is the most common congenital muscular dystrophy, affecting approximately 4 in 500,000 children. The most common cause of death in early-onset LAMA2 MD is respiratory tract infection, with 30% of them dying within the first decade of life. LAMA2 MD is caused by loss-of-function mutations in the LAMA2 gene encoding for the laminin-α2 chain, one of the subunits of laminin-211. Laminin-211 is an extracellular matrix protein that functions to stabilize the basement membrane and muscle fibers during contraction. Since laminin-α2 is expressed in many tissue types including skeletal muscle, cardiac muscle, Schwann cells, and trophoblasts, patients with LAMA2 MD experience a multi-systemic clinical presentation depending on the extent of laminin-α2 chain deficiency. Cardiac manifestations are typically associated with a complete absence of laminin-α2; however, recent case reports highlight cardiac involvement in partial laminin-α2 chain deficiency. Laminin-211 is also expressed in the brain, and many patients have abnormalities on brain imaging; however, mental retardation and/or seizures are rarely seen. Currently, there is no cure for LAMA2 MD, but various therapies are being investigated in an effort to lessen the severity of LAMA2 MD. For example, antisense oligonucleotide-mediated exon skipping and CRISPR-Cas9 genome editing have efficiently restored the laminin-α2 chain in mouse models in vivo. This review consolidates information on the clinical presentation, genetic basis, pathology, and current treatment approaches for LAMA2 MD.","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"12 1","pages":"113 - 130"},"PeriodicalIF":3.1,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2147/TACG.S187481","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43560479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Zastrozhin, V. Skryabin, S. S. Miroshkin, E. Bryun, D. Sychev
{"title":"Pharmacogenetics of alcohol addiction: current perspectives","authors":"M. Zastrozhin, V. Skryabin, S. S. Miroshkin, E. Bryun, D. Sychev","doi":"10.2147/TACG.S206745","DOIUrl":"https://doi.org/10.2147/TACG.S206745","url":null,"abstract":"Abstract Genetics of alcohol addiction is currently a contradictive and complex field, where data in the most studies reflect methods’ limitations rather than meaningful and complementary results. In our review, we focus on the genetics of alcohol addiction, leaving genetics of acute alcohol intoxication out of the scope. A review of the literature on pharmacogenetic biomarkers development for the pharmacotherapy personalization reveals that today the evidence base concerning these biomarkers is still insufficient. In particular, now the researches with the design of randomized controlled trials and meta-analysis investigating the effect of the SNPs as biomarkers on the therapy efficacy are available for naltrexone only. For other medications, there are only a few studies in small samples. It decreases the possibilities to implement the pharmacogenetic algorithms for the pharmacotherapy personalization in patients with alcohol use disorders (AUD). In view of the importance of the precision approaches development not in addiction medicine only, but in other fields of medicine also to increase the efficacy and safety of the therapy, studies on pharmacogenetic biomarkers development for the medications used in patients with AUD (eg, naltrexone, disulfiram, nalmefene, acamprosate, etc.) remain relevant to this day.","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"12 1","pages":"131 - 140"},"PeriodicalIF":3.1,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2147/TACG.S206745","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42892515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ashley M Lane, Jerome T McKay, Herbert L Bonkovsky
{"title":"Advances in the management of erythropoietic protoporphyria - role of afamelanotide.","authors":"Ashley M Lane, Jerome T McKay, Herbert L Bonkovsky","doi":"10.2147/TACG.S122030","DOIUrl":"10.2147/TACG.S122030","url":null,"abstract":"<p><p>Erythropoietic protoporphyria (EPP) and the phenotypically similar disease X-linked protoporphyria (XLPP) are inherited cutaneous porphyrias characterized clinically by acute non-blistering photosensitivity, intolerance to sunlight, and significantly reduced quality of life. They are due to marked overproduction of protoporphyrin (PP) chiefly by erythroblasts and reticulocytes. In EPP, the underlying genetic defect is in the ferrochelatase gene, which encodes the final enzyme in the heme synthetic pathway. In XLPP, the genetic defect is a gain-of-function mutation, usually a four-base deletion, in the gene that encodes the enzyme 5-aminolevulinic acid synthase-2, the first and rate-controlling enzyme of heme synthesis in developing red blood cells. The excess PP causes acute and painful photosensitivity, being activated by light in the long ultraviolet to blue spectrum (380-420 nm, the Soret band). Although several treatments have been proposed, presently no very effective treatment exists for EPP or XLPP. Afamelanotide (Scenesse<sup>®</sup>) is a first-in-class synthetic analog of α-melanocyte stimulating hormone. Afamelanotide mimics the naturally occurring hormone to increase skin pigmentation by increasing melanin production in melanocytes, resulting in increased sunlight tolerance in those with EPP/XLPP. Afamelanotide is currently approved for use in the European Union and Switzerland, and it is under review in the United States by the Food and Drug Administration for use in patients with EPP/XLPP. This paper provides a review of the clinical characteristics and current therapies for EPP/XLPP. We discuss the pharmacology, clinical efficacy, safety, and tolerability of afamelanotide and summarize the results of several key Phase II and III clinical trials. These data indicate that afamelanotide is a promising therapy for those with these debilitating diseases.</p>","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"9 1","pages":"179-189"},"PeriodicalIF":3.1,"publicationDate":"2016-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2147/TACG.S122030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68481392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Romdhane Rekaya, Shannon Smith, El Hamidi Hay, Nourhene Farhat, Samuel E Aggrey
{"title":"Analysis of binary responses with outcome-specific misclassification probability in genome-wide association studies.","authors":"Romdhane Rekaya, Shannon Smith, El Hamidi Hay, Nourhene Farhat, Samuel E Aggrey","doi":"10.2147/TACG.S122250","DOIUrl":"10.2147/TACG.S122250","url":null,"abstract":"<p><p>Errors in the binary status of some response traits are frequent in human, animal, and plant applications. These error rates tend to differ between cases and controls because diagnostic and screening tests have different sensitivity and specificity. This increases the inaccuracies of classifying individuals into correct groups, giving rise to both false-positive and false-negative cases. The analysis of these noisy binary responses due to misclassification will undoubtedly reduce the statistical power of genome-wide association studies (GWAS). A threshold model that accommodates varying diagnostic errors between cases and controls was investigated. A simulation study was carried out where several binary data sets (case-control) were generated with varying effects for the most influential single nucleotide polymorphisms (SNPs) and different diagnostic error rate for cases and controls. Each simulated data set consisted of 2000 individuals. Ignoring misclassification resulted in biased estimates of true influential SNP effects and inflated estimates for true noninfluential markers. A substantial reduction in bias and increase in accuracy ranging from 12% to 32% was observed when the misclassification procedure was invoked. In fact, the majority of influential SNPs that were not identified using the noisy data were captured using the proposed method. Additionally, truly misclassified binary records were identified with high probability using the proposed method. The superiority of the proposed method was maintained across different simulation parameters (misclassification rates and odds ratios) attesting to its robustness.</p>","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"9 ","pages":"169-177"},"PeriodicalIF":3.1,"publicationDate":"2016-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138056/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140289093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Novel treatment options for lysosomal acid lipase deficiency: critical appraisal of sebelipase alfa.","authors":"Kim Su, Emma Donaldson, Reena Sharma","doi":"10.2147/TACG.S86760","DOIUrl":"10.2147/TACG.S86760","url":null,"abstract":"<p><p>Lysosomal acid lipase deficiency (LAL-D) is a rare disorder of cholesterol metabolism with an autosomal recessive mode of inheritance. The absence or deficiency of the LAL enzyme gives rise to pathological accumulation of cholesterol esters in various tissues. A severe LAL-D phenotype manifesting in infancy is associated with adrenal calcification and liver and gastrointestinal involvement with characteristic early mortality. LAL-D presenting in childhood and adulthood is associated with hepatomegaly, liver fibrosis, cirrhosis, and premature atherosclerosis. There are currently no curative pharmacological treatments for this life-threatening condition. Supportive management with lipid-modifying agents does not ameliorate disease progression. Hematopoietic stem cell transplantation as a curative measure in infantile disease has mixed success and is associated with inherent risks and complications. Sebelipase alfa (Kanuma) is a recombinant human LAL protein and the first enzyme replacement therapy for the treatment of LAL-D. Clinical trials have been undertaken in infants with rapidly progressive LAL-D and in children and adults with later-onset LAL-D. Initial data have shown significant survival benefits in the infant group and improvements in biochemical parameters in the latter. Sebelipase alfa has received marketing authorization in the United States and Europe as long-term therapy for all affected individuals. The availability of enzyme replacement therapy for this rare and progressive disorder warrants greater recognition and awareness by physicians.</p>","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"9 1","pages":"157-167"},"PeriodicalIF":3.1,"publicationDate":"2016-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5074735/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68482200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karen Sánchez, Elizabeth de Mendonca, Xiorama Matute, I. Chaustre, M. Villalón, Howard Takiff
{"title":"Analysis of the CFTR gene in Venezuelan cystic fibrosis patients, identification of six novel cystic fibrosis-causing genetic variants","authors":"Karen Sánchez, Elizabeth de Mendonca, Xiorama Matute, I. Chaustre, M. Villalón, Howard Takiff","doi":"10.2147/TACG.S78241","DOIUrl":"https://doi.org/10.2147/TACG.S78241","url":null,"abstract":"The mutations in the CFTR gene found in patients with cystic fibrosis (CF) have geographic differences, but there are scant data on their prevalence in Venezuelan patients. This study determined the frequency of common CFTR gene mutations in a group of Venezuelan patients with CF. The 27 exons of the CFTR gene from 110 Venezuelan patients in the National CF Program were amplified and sequenced. A total of 36 different mutations were identified, seven with frequencies greater than 1%: p.Phe508del (27.27%), p.Gly542* (3.18%), c.2988+1G>A (3.18%), p.Arg334Trp (1.36%), p.Arg1162* (1.36%), c.1-8G>C (1.36%), and p.[Gly628Arg;Ser1235Arg](1.36). In 40% of patients, all with a clinical diagnosis of CF, no mutations were found. This report represents the largest cohort of Venezuelan patients with CF ever examined, and includes a wider mutation panel than has been previously studied in this population. Mutations common in Southern European populations predominate, and several new mutations were discovered, but no mutations were found in 40% of the cohort.","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"9 1","pages":"33 - 38"},"PeriodicalIF":3.1,"publicationDate":"2016-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2147/TACG.S78241","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68481858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Candidate genes of idiopathic pulmonary fibrosis: current evidence and research.","authors":"Wei Zhou, Yaping Wang","doi":"10.2147/TACG.S61999","DOIUrl":"https://doi.org/10.2147/TACG.S61999","url":null,"abstract":"<p><p>Idiopathic pulmonary fibrosis (IPF) is a group of common and lethal forms of idiopathic interstitial pulmonary disease. IPF is characterized by a progressive decline in lung function with a median survival of 2-3 years after diagnosis. Although the pathogenesis of the disease remains unknown, genetic predisposition could play a causal role in IPF. A set of genes have been identified as candidate genes of IPF in the past 20 years. However, the recent technological advances that allow for the analysis of millions of polymorphisms in different subjects have deepened the understanding of the genetic complexity of IPF susceptibility. Genome-wide association studies and whole-genome sequencing continue to reveal the genetic loci associated with IPF risk. In this review, we describe candidate genes on the basis of their functions and aim to gain a better understanding of the genetic basis of IPF. The discovered candidate genes may help to clarify pivotal aspects in the diagnosis, prognosis, and therapies of IPF. </p>","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"9 ","pages":"5-13"},"PeriodicalIF":3.1,"publicationDate":"2016-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4745857/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140194734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Hoyle, M. Isfort, J. Roggenbuck, D. Arnold, C. hoyle
{"title":"The genetics of Charcot–Marie–Tooth disease: current trends and future implications for diagnosis and management","authors":"J. Hoyle, M. Isfort, J. Roggenbuck, D. Arnold, C. hoyle","doi":"10.2147/TACG.S69969","DOIUrl":"https://doi.org/10.2147/TACG.S69969","url":null,"abstract":"Charcot–Marie–Tooth (CMT) disease is the most common hereditary polyneuropathy and is classically associated with an insidious onset of distal predominant motor and sensory loss, muscle wasting, and pes cavus. Other forms of hereditary neuropathy, including sensory predominant or motor predominant forms, are sometimes included in the general classification of CMT, but for the purpose of this review, we will focus primarily on the forms associated with both sensory and motor deficits. CMT has a great deal of genetic heterogeneity, leading to diagnostic considerations that are still rapidly evolving for this disorder. Clinical features, inheritance pattern, gene mutation frequencies, and electrodiagnostic features all are helpful in formulating targeted testing algorithms in practical clinical settings, but these still have shortcomings. Next-generation sequencing (NGS), combined with multigene testing panels, is increasing the sensitivity and efficiency of genetic testing and is quickly overtaking targeted testing strategies. Currently, multigene panel testing and NGS can be considered first-line in many circumstances, although obtaining initial targeted testing for the PMP22 duplication in CMT patients with demyelinating conduction velocities is still a reasonable strategy. As technology improves and cost continues to fall, targeted testing will be completely replaced by multigene NGS panels that can detect the full spectrum of CMT mutations. Nevertheless, clinical acumen is still necessary given the variants of uncertain significance encountered with NGS. Despite the current limitations, the genetic diagnosis of CMT is critical for accurate prognostication, genetic counseling, and in the future, specific targeted therapies. Although whole exome and whole genome sequencing strategies have the power to further elucidate the genetics of CMT, continued technological advances are needed.","PeriodicalId":39131,"journal":{"name":"Application of Clinical Genetics","volume":"8 1","pages":"235 - 243"},"PeriodicalIF":3.1,"publicationDate":"2015-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2147/TACG.S69969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68481709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}