A novel synonymous KMT2B variant in a patient with dystonia causes aberrant splicing

BACKGROUND: Heterozygous KMT2B variants are a common cause of dystonia. A novel synonymous KMT2B variant, c.5073C>T (p.Gly1691=) was identified in an individual with childhood-onset progressive dystonia. METHODS: The splicing impact of c.5073C>T was assessed using an in vitro exon-trapping assay. The genomic region of KMT2B exons 23-26 was cloned into the pSpliceExpress plasmid between exon 2 and 3 of the rat Ins2 gene. The c.5073C>T variant was then introduced through site-directed mutagenesis. The KMT2B wild-type and c.5073C>T plasmids were transfected separately into HeLa cells and RNA was extracted 48 hours after transfection. The RNA was reverse transcribed to produce cDNA, which was PCR amplified using primers annealing to the flanking rat Ins2 sequences. RESULTS: Sanger sequencing of the PCR products revealed that c.5073C>T caused a novel splice donor site and therefore a 5-bp deletion of KMT2B exon 23 in mature mRNA, leading to a coding frameshift and premature stop codon (p.Lys1692AsnfsTer7). CONCLUSION: To our knowledge, this is the first report of a KMT2B synonymous variant associated with dystonia. Reassessment of synonymous variants may increase diagnostic yield for inherited disorders including monogenic dystonia. This is of clinical importance, given the generally favourable response to deep brain stimulation for KMT2B-related dystonia

Alternative laronidase dose regimen for patients with mucopolysaccharidosis I: a multinational, retrospective, chart review case series

Background: Enzyme replacement therapy (ERT) with laronidase (recombinant human alpha-L-iduronidase, Aldurazyme (R)) is indicated for non-neurological signs and symptoms of mucopolysaccharidosis type I (MPS I). The approved laronidase dose regimen is weekly infusions of 0.58mg/kg, however, patients and caregivers may have difficulty complying with the weekly regimen. We examined clinical outcomes, tolerability, compliance, and satisfaction in a series of patients who switched to every other week infusions. Methods: This multinational, retrospective, chart review case series analyzed data from 20 patients who had undergone ERT with laronidase 0.58mg/kg weekly for more than one year, and who then switched to 1.2mg/kg every other week. Results: The majority of patients had attenuated MPS I phenotypes (9 with Hurler-Scheie and 8 with Scheie syndromes) and 3 patients had severe MPS I (Hurler syndrome). Most patients presented with organomegaly (17/ 20), umbilical and/or inguinal hernia (16/20), cardiac abnormalities (17/20), musculoskeletal abnormalities (19/20), and neurological and/or developmental deficits (15/20). Following laronidase treatment, signs stabilized or improved. No deterioration or reversal of clinical outcome was noted in any patient who switched from the weekly dose of 0.58mg.kg to 1.2mg/kg every other week. There were no safety issues during the duration of every other week dosing. Patient compliance and satisfaction with the dosing regimen were greater with every other week dosing than weekly dosing. Conclusions: An alternative dose regimen of 1.2mg/kg laronidase every other week was well tolerated and clinically similar to the standard dose for patients who were stabilized with weekly 0.58 mg/kg for one year or more. When an individualized approach to laronidase therapy is necessary, every other week dosing may be an alternative for patients with difficulty receiving weekly infusions.Sanofi GenzymeSanofi Genzyme, Cambridge, MA, USAFiocruz MS, Inst Nacl Saude Mulher Crianca & Adolescente Fern, BR-21045900 Rio De Janeiro, BrazilUniv Fed Bahia, Dept Pediat, Serv Genet Med, Salvador, BA, BrazilHosp Clin Alegre, Med Genet Serv, Porto Alegre, RS, BrazilComenius Univ, Childrens Hosp, Dept Pediat 2, Bratislava, SlovakiaWestmead Hosp, Dept Med Genet, Sydney, NSW, AustraliaUniv Sydney, Sydney, NSW 2006, AustraliaUniv Fed Sao Paulo, Dept Pediat, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Pediat, Sao Paulo, BrazilWeb of Scienc

Whole genome sequencing for the genetic diagnosis of heterogenous dystonia phenotypes

Introduction: Dystonia is a clinically and genetically heterogeneous disorder and a genetic cause is often difficult to elucidate. This is the first study to use whole genome sequencing (WGS) to investigate dystonia in a large sample of affected individuals. Methods: WGS was performed on 111 probands with heterogenous dystonia phenotypes. We performed analysis for coding and non-coding variants, copy number variants (CNVs), and structural variants (SVs). We assessed for an association between dystonia and 10 known dystonia risk variants. Results: A genetic diagnosis was obtained for 11.7% (13/111) of individuals. We found that a genetic diagnosis was more likely in those with an earlier age at onset, younger age at testing, and a combined dystonia phenotype. We identified pathogenic/likely-pathogenic variants in ADCY5 (n = 1), ATM (n = 1), GNAL (n = 2), GLB1 (n = 1), KMT2B (n = 2), PRKN (n = 2), PRRT2 (n = 1), SGCE (n = 2), and THAP1 (n = 1). CNVs were detected in 3 individuals. We found an association between the known risk variant ARSG rs11655081 and dystonia (p = 0.003). Conclusion: A genetic diagnosis was found in 11.7% of individuals with dystonia. The diagnostic yield was higher in those with an earlier age of onset, younger age at testing, and a combined dystonia phenotype. WGS may be particularly relevant for dystonia given that it allows for the detection of CNVs, which accounted for 23% of the genetically diagnosed cases. © 2019 The Author

Efficacy and safety of D,L-3-hydroxybutyrate (D,L-3-HB) treatment in multiple acyl-CoA dehydrogenase deficiency

PURPOSE: Multiple acyl-CoA dehydrogenase deficiency (MADD) is a life-threatening, ultrarare inborn error of metabolism. Case reports described successful D,L-3-hydroxybutyrate (D,L-3-HB) treatment in severely affected MADD patients, but systematic data on efficacy and safety is lacking.METHODS: A systematic literature review and an international, retrospective cohort study on clinical presentation, D,L-3-HB treatment method, and outcome in MADD(-like) patients.RESULTS: Our study summarizes 23 MADD(-like) patients, including 14 new cases. Median age at clinical onset was two months (interquartile range [IQR]: 8 months). Median age at starting D,L-3-HB was seven months (IQR: 4.5 years). D,L-3-HB doses ranged between 100 and 2600 mg/kg/day. Clinical improvement was reported in 16 patients (70%) for cardiomyopathy, leukodystrophy, liver symptoms, muscle symptoms, and/or respiratory failure. D,L-3-HB appeared not effective for neuropathy. Survival appeared longer upon D,L-3-HB compared with historical controls. Median time until first clinical improvement was one month, and ranged up to six months. Reported side effects included abdominal pain, constipation, dehydration, diarrhea, and vomiting/nausea. Median D,L-3-HB treatment duration was two years (IQR: 6 years). D,L-3-HB treatment was discontinued in 12 patients (52%).CONCLUSION: The strength of the current study is the international pooling of data demonstrating that D,L-3-HB treatment can be effective and safe in MADD(-like) patients.</p

Metastatic prostate cancer mimicking primary osteosarcoma of the jaw: an infrequent clinical case.

Prostate cancer metastasizing to the mandible is a rare occurrence. This case describes a patient whose presenting symptom was a painless swelling of the left mandible. Radiological investigation demonstrated a lesion within the left mandibular ramus, and subsequent biopsy confirmed the diagnosis of metastatic prostate cancer

A patient with recurrent disabling atrial fibrillation and Fabry cardiomyopathy successfully treated with single ring pulmonary vein isolation

Letter to the editor

Novel Mutations Found in Individuals with Adult-Onset Pompe Disease

Pompe disease, or glycogen storage disease II is a rare, progressive disease leading to skeletal muscle weakness due to deficiency of the acid &alpha;-1,4-glucosidase enzyme (GAA). The severity of disease and observed time of onset is subject to the various combinations of heterozygous GAA alleles. Here we have characterized two novel mutations: c.2074C&gt;T and c.1910_1918del, and a previously reported c.1082C&gt;G mutation of uncertain clinical significance. These mutations were found in three unrelated patients with adult-onset Pompe disease carrying the common c.-32-13T&gt;G mutation. The c.2074 C&gt;T nonsense mutation has obvious consequences on GAA expression but the c.1910_1918del (deletion of 3 amino acids) and c.1082C&gt;G missense variants are more subtle DNA changes with catastrophic consequences on GAA activity. Molecular and clinical analyses from the three patients corresponded with the anticipated pathogenicity of each mutation

Cognitive and psychological functioning in fabry disease

Fabry disease is an X-linked lysosomal storage disorder which can result in renal, cardiac, and cerebrovascular disease. Patients are at increased risk of stroke and neuroimaging studies note cerebrovascular pathology. This study provides a cognitive profile of a cohort of individuals with Fabry disease and investigates the impact of pain, age, renal, cardiac, and cerebrovascular functioning on cognition and psychological functioning. Seventeen Fabry patients (12 males) with ages ranging 25 to 60 years (M = 46.6+11.8), and 15 age-matched healthy controls (M = 46.2+12.7) were administered a comprehensive neuropsychological battery. Fabry males demonstrated slower speed of information processing, reduced performance on measures of executive functions (verbal generation, reasoning, problem solving, perseveration), were more likely to show clinically significant reductions, and were more likely to report symptoms of anxiety and depression. Conversely, Fabry females performed at a similar level to controls. Correlational analyses indicated a link between cognitive and clinical measures of disease severity.9 page(s

Klinefelter syndrome with fabry disease - a case of nondisjunction of the x-chromosome with sex-linked recessive mutation

A 52 year-old male with Klinefelter syndrome presented with chest tightness and rapid atrial fibrillation with hypotension. His echocardiogram demonstrated symmetrical left ventricular hypertrophy with minimal diastolic dysfunction. Subsequent investigations confirmed the diagnosis of Fabry cardiomyopathy. This is the first reported case of Klinefelter syndrome with homozygous sex-linked recessive mutation presenting primarily with cardiac manifestation