Mutation detection by analysis of DNA heteroduplexes in TILLING populations of diploid species

In the beginning of mutation research, mutations could only be detected indirectly through the analysis of the phenotypic alterations that they caused. The detection of mutations at the DNA level became possible with the development of sequencing methods. Nowadays, there are many different methods and strategies that have been created for mutation detection, both in natural and mutagenised populations. The strategies differ in accuracy and sensitivity, as well as in the laboratory facilities, time, costs and efforts that are required. The majority of them involve the pooling of DNA samples and the amplification of a gene (fragment) of interest followed by heteroduplex formation. One of the popular strategies for mutation identification takes advantage of the specific endonuclease (e.g. CEL I) that recognises and cuts heteroduplexes precisely at the 3′ position of the mismatch site. The cleaved fragments are usually visualised through electrophoresis in a polyacrylamide gel using LI-COR sequencers, but agarose electrophoresis may also be used for this purpose, although with less sensitivity. A different mutation identification strategy, which is based on the high-resolution melting (HRM) technique, may be the method of choice when working with a short gene or a gene fragment whose length optimally does not exceed 400 bp

Severe infantile hypotonia with ethylmalonic aciduria: Case report

An 8-month-old girl was admitted to an outpatient clinic with significant hypotonia and weakness. Organic acid analysis in urine revealed a significant increase in ethylmalonic acid. A deoxyribonucleic analysis revealed the presence of a 625G>A (G-to-A substitution at nucleotide 625) variant short-chain acyl-coenzyme A dehydrogenase gene polymorphism. With the clinical, biochemical and molecular findings, short-chain acyl-coenzyme A dehydrogenase deficiency was suspected. Because 625G>A and 511C>T (C-to-T substitution at nucleotide 511) genetic variations are also present in 14% of the general population, these are considered to be genetic sensitivity variations rather than causing a disease themselves and to result in possible short-chain acyl-coenzyme A dehydrogenase deficiency in the presence of environmental factors such as fever and hunger as well as cellular, biochemical, and other genetic factors. It was stressed that severe infantile hypotonia could also be the only manifestation of ethylmalonic aciduria spectrum disorders. \ua9 2008 Sage Publication

A 7-YEAR-OLD BOY WITH HAND TREMORS AND A NOVEL MUTATION FOR L-2-HYDROXYGLUTARIC ACIDURIA

L-2-hydroxyglutaric aciduria (L2HGA), which is a rare autosomal recessive metabolic disorder caused by mutations in the encoding L2HGDH gene. Neurological symptoms are the main predominant clinical signs. The distinctive feature is the specific multifocal lesion of the white matter detected on magnetic resonance imaging (MRI). A 7-year-old male patient of Turkish origin was admitted to the hospital because of hand tremors. Physical examination revealed macrocephaly, intention tremors, walking disability and ataxic gait. Urine organic acid analysis showed increased excretion of L-2-hydroxyglutaric acid (L2HG acid). Analysis of the L2HGDH gene revealed a novel homozygous c.368A>G, p. (Tyr123Cys) mutation. L-2-hydroxyglutaric aciduria is a cerebral organic aciduria that may lead to various neurological complications. Early recognition of symptoms of L2HGA is important for initiation of supportive therapy that may slow down the progression of the disease

EFFICACY AND SAFETY OF SEBELIPASE ALFA IN CHILDREN AND ADULTS WITH LYSOSOMAL ACID LIPASE DEFICIENCY: RESULTS OF A PHASE 3 TRIAL

50th International Liver Congress of the European-Association-for-the-Study-of-the-Liver -- APR 22-26, 2015 -- Vienna, AUSTRIAWOS: 000362830900402European Assoc Study Live

Mucopolysaccharidosis type IIID: 12 new patients and 15 novel mutations.

Contains fulltext : 89263.pdf (publisher's version ) (Closed access)Mucopolysaccharidosis III D (Sanfilippo disease type D, MPS IIID) is a rare autosomal recessive lysosomal storage disorder previously described in only 20 patients. MPS IIID is caused by a deficiency of N-acetylglucosamine-6-sulphate sulphatase (GNS), one of the enzymes required for the degradation of heparan sulphate. So far only seven mutations in the GNS gene have been reported. The clinical phenotype of 12 new MPS IIID patients from 10 families was studied. Mutation analysis of GNS was performed in 16 patients (14 index cases). Clinical signs and symptoms of the MPS IIID patients appeared to be similar to previously described patients with MPS III. Early development was normal with onset of behavioral problems around the age of 4 years, followed by developmental stagnation, deterioration of verbal communication and subsequent deterioration of motor functions. Sequence analysis of the coding regions of the gene encoding GNS (GNS) resulted in the identification of 15 novel mutations: 3 missense mutations, 1 nonsense mutation, 4 splice site mutations, 3 frame shift mutations, 3 large deletions and 1 in-frame small deletion. They include the first missense mutations and a relatively high proportion of large rearrangements, which warrants the inclusion of quantitative techniques in routine mutation screening of the GNS gene.1 mei 201

A phase 3 trial of sebelipase alfa in lysosomal acid lipase deficiency

Background: Lysosomal acid lipase is an essential lipid-metabolizing enzyme that breaks down endocytosed lipid particles and regulates lipid metabolism. We conducted a phase 3 trial of enzyme-replacement therapy in children and adults with lysosomal acid lipase deficiency, an underappreciated cause of cirrhosis and severe dyslipidemia. Methods: In this multicenter, randomized, double-blind, placebo-controlled study involving 66 patients, we evaluated the safety and effectiveness of enzyme-replacement therapy with sebelipase alfa (administered intravenously at a dose of 1 mg per kilogram of body weight every other week); the placebo-controlled phase of the study was 20 weeks long and was followed by open-label treatment for all patients. The primary end point was normalization of the alanine aminotransferase level. Secondary end points included additional disease-related efficacy assessments, safety, and side-effect profile. Results: Substantial disease burden at baseline included a very high level of low-density lipoprotein cholesterol (≥190 mg per deciliter) in 38 of 66 patients (58%) and cirrhosis in 10 of 32 patients (31%) who underwent biopsy. A total of 65 of the 66 patients who underwent randomization completed the double-blind portion of the trial and continued with open-label treatment. At 20 weeks, the alanine aminotransferase level was normal in 11 of 36 patients (31%) in the sebelipase alfa group and in 2 of 30 (7%) in the placebo group (P = 0.03), with mean changes from baseline of -58 U per liter versus -7 U per liter (P<0.001). With respect to prespecified key secondary efficacy end points, we observed improvements in lipid levels and reduction in hepatic fat content (P<0.001 for all comparisons, except P = 0.04 for triglycerides). The number of patients with adverse events was similar in the two groups; most events were mild and were considered by the investigator to be unrelated to treatment. Conclusions: Sebelipase alfa therapy resulted in a reduction in multiple disease-related hepatic and lipid abnormalities in children and adults with lysosomal acid lipase deficiency. (Funded by Synageva BioPharma and others; ARISE ClinicalTrials.gov number, NCT01757184.

A Phase 3 Trial of Sebelipase Alfa in Lysosomal Acid Lipase Deficiency

BACKGROUND Lysosomal acid lipase is an essential lipid-metabolizing enzyme that breaks down endocytosed lipid particles and regulates lipid metabolism. We conducted a phase 3 trial of enzyme-replacement therapy in children and adults with lysosomal acid lipase deficiency, an underappreciated cause of cirrhosis and severe dyslipidemia. METHODS In this multicenter, randomized, double-blind, placebo-controlled study involving 66 patients, we evaluated the safety and effectiveness of enzyme-replacement therapy with sebelipase alfa (administered intravenously at a dose of 1 mg per kilogram of body weight every other week); the placebo-controlled phase of the study was 20 weeks long and was followed by open-label treatment for all patients. The primary end point was normalization of the alanine aminotransferase level. Secondary end points included additional disease-related efficacy assessments, safety, and side-effect profile. RESULTS Substantial disease burden at baseline included a very high level of low-density lipoprotein cholesterol (>= 190 mg per deciliter) in 38 of 66 patients (58\%) and cirrhosis in 10 of 32 patients (31\%) who underwent biopsy. A total of 65 of the 66 patients who underwent randomization completed the double-blind portion of the trial and continued with open-label treatment. At 20 weeks, the alanine aminotransferase level was normal in 11 of 36 patients (31\%) in the sebelipase alfa group and in 2 of 30 (7\%) in the placebo group (P = 0.03), with mean changes from baseline of -58 U per liter versus -7 U per liter (P<0.001). With respect to pre-specified key secondary efficacy end points, we observed improvements in lipid levels and reduction in hepatic fat content (P<0.001 for all comparisons, except P = 0.04 for triglycerides). The number of patients with adverse events was similar in the two groups; most events were mild and were considered by the investigator to be unrelated to treatment. CONCLUSIONS Sebelipase alfa therapy resulted in a reduction in multiple disease-related hepatic and lipid abnormalities in children and adults with lysosomal acid lipase deficiency. (Funded by Synageva BioPharma and others; ARISE ClinicalTrials.gov number, NCT01757184.