- Email: [email protected]
Genetic profile of Brazilian patients with dystrophinopathies
Abstracts 2016 / Neuromuscular Disorders 26 (2016) S88–S212 expression, with high probability compatible with dystrophinopathy, was demonstrated in muscle biopsy. Initial analysis did not reveal a genetic mutation. At the age of five a hemizygote duplication of exon 56 of the DMD gene was revealed. At that time his endurance was slightly reduced, stair climbing was becoming a little more difficult and pseudohypertrophy of the lower legs was noted. At the age of seven, waddling gait and a positive Gowers’ sign was reported. He complained of episodes of intense pain and stiffness in his legs. He was started on glucocorticoids with motor improvement, and his motor abilities have remained relatively stable through the subsequent years. He developed rhabdomyolysis related to elective anaesthesia at the age of 12, when, unfortunately, inhalation agents were given. Thereafter he has had four episodes perceived as rhabdomyolysis of uncertain origin. He has a mild mental retardation and an individualised education plan. In his 12th year he experienced a period of quite severe depressive symptoms. During the last year he has had episodes of severe emotional and behavioural disturbance, often with anxiety, compulsion and depression, but also with aggression, agitation and near-psychotic traits. These episodes seem to appear in a cyclic pattern with no identifiable initiating events. Risperidone has been given with some effect. He is currently being weaned off glucocorticoids. The phenotype will be further discussed, also in relation to genotype. http://dx.doi.org/10.1016/j.nmd.2016.06.044
P.23 Russian experience of DMD genetic database D. Vlodavets 1,2, D. Reshetov 1,2, S. Artemieva 1,2, E. Litvinova 1,2, I. Shulyakova 1,2, O. Shidlovskaya 1,2, D. Kazakov 1,2, E. Belousova 1,2 1 Veltischev Clinical Pediatric Research Institute of Pirogov Russian National Research Medical University, Moscow, Russia; 2 Marlin Biotech LLC, Moscow, Russia We present a genetic database of DMD and BMD patients of Russian neuromuscular center. At present, our DNA genetic database includes more than 180 patients from all over Russia. Primary cell cultures database consists of 100 samples. Our data include information about 174 DMD and 6 BMD boys. We still have 29 patients with clear DMD clinical manifestations with no genetic confirmation (they have been excluded from this analysis). From a recent cohort of 151 patients with proved mutations in DMD gene we detected 32 (21,2%) patients with different point mutations, 20 (13,2%) patients with exons duplications and 99 (65,6%) with different exons deletions. Only 55 (36,4%) patients could be treated with different exon skipping technologies. In theory, it is possible to treat about 50% of DMD patients by exon skipping technologies and about 10% could be treated by technologies correcting point STOP-mutations, both aimed to restore reading frame of DMD gene. 51 exon skipping technology could be relevant for 13% of DMD boys, skipping exons 45 and 53 – 8% for each, 44 – 6%, 52, 50 and 43 – 4%, 55 and 8 – 2% for each. In our cohort this theory was proven only in quantity of patients with STOPmutations only, which occurred in 15 (9,9%) patients. Exon skipping applicability in our cohort was: for 51 – 15 (9,9%) patients, for 45 – 12 (7,9%), for 53 – 6 (3,9%) patients, for 44 – 12 (7,9%) patients, for 52 – 5 (3,3%), for 55 – 2 (1,32%) patients, for 8 – 1 (0,66%) patient, and for 50, 43 and 17 no one. We continue to add patients in our database with the goal of being ready for the emergence of new drugs. In new era of targeted treatment of genetic disorders it is very important to collect information in databases. http://dx.doi.org/10.1016/j.nmd.2016.06.045
P.24 Genetic profile of Brazilian patients with dystrophinopathies L. Sauma, P. Ducceschi, C. Iwabe-Marchese, T. Rosa, A. Nucci, M. França Jr Universidade Estadual de Campinas-UNICAMP, Campinas, Brazil Duchenne (DMD) and Becker (BMD) muscular dystrophies are the most frequent myopathies in children and caused by mutations in the DMD gene.
S97
Little is known about the genetic profile of DMD/BMD in Brazilian patients. This information is important because mutation-specific genetic therapies are shortly coming. To characterize the genetic profile of Brazilian patients with DMD/BMD, we selected all patients with molecular diagnosis of dystrophinopathies followed at UNICAMP neuromuscular outpatient clinic between March 2015 and 2016. Each patient underwent molecular investigation that included MLPA and gene sequencing (small mutations). For those variants not previously reported, we looked at the available SNP and mutation databases (1000 genomes consortium, ExAC, NCBI and Ensembl) and also performed in silico analyses using different tools (Mutation taster, Polyphen2, Sift). We collected data on age at disease onset and duration and disease severity (using the MFM scale) in order to compare patients with large vs small mutations. We recruited 41 patients. Mean age at disease onset was 3.3 years (range 1–10); 19 patients were wheelchair users and 22 ambulant. Large deletions and duplications were found in 30 (73.2%) and point mutations in 9 (26.8%). In the later group, nonsense mutations were found in 3 patients from 2 unrelated families (7,3%) and frameshift mutations in 6 patients from 5 unrelated families (14.6%). We identify a novel intronic mutation (c.2803 + 5G > C) that was found in two brothers, one DMD other BMD phenotype. Genotype–phenotype analyses revealed no significant difference between patients with small vs large mutations in terms of disease progression and age at onset. Large deletions and duplications at the DMD gene are the most frequent genetic substrate in Brazilian patients. Small mutations were found in 26.8% of the patients. This profile is similar to that reported in European and North American cohorts. http://dx.doi.org/10.1016/j.nmd.2016.06.046
P.25 Variations in Duchenne muscular dystrophy clinical course in a multi-ethnic UK population: Are there potential influencing factors other than genetic modifiers? H. Roper, M. Hufton Birmingham Heartlands Hospital, Birmingham, UK Genetic modifiers have been identified as influencing disease course in Duchenne muscular dystrophy, particularly LTBP4 haplotype. In a single UK clinic population – serving a diverse multi-ethnic population with high levels of deprivation – we noted an apparent more severe clinical course in boys of south Asian ethnic origin and also an apparent tendency to refuse or defer steroid therapy. We explored these observations to see if they were borne out to indicate potentially modifiable factors. From 2005 to 2014, 71 children from 68 families were newly diagnosed with DMD. Their ethnic origin was white British 35, South Asian 23, white European 3, mixed heritage 7, other Asian 2, black African 1. Mean age at diagnosis (for those without known family history) was 45.5months; for white British 44.3 months (range 14–80) and for South Asians 50.2 months (range 5–98). 24 boys lost ambulation, 45 are still walking at age 4y5m – 15y9m (2 moved away). 10% of white British who had reached 9th birthday by the end of the study period had LOA whereas 53% of south Asian who had reached 9th birthday had LOA. Age starting steroids was similar in all groups; about 25% had a delay in starting steroids of >6 months; 17% of south Asians declined steroids compared to 10% white British. 47% of south Asians stopped steroids compared to 19% of white British. For the whole group, those most deprived – in the bottom 20% socioeconomically – did worse (none in the top 20% had LOA by 9y whereas 54% of the bottom 20% had LOA by 9y) but there was no difference in steroid usage and the more socially deprived 20% were diagnosed earlier and started steroids earlier. 64% of white British were in the lower 50% socioeconomically, compared to 71% of South Asians. 20% of white British were in the bottom 20% socioeconomically, compared to 47% of the South Asians. http://dx.doi.org/10.1016/j.nmd.2016.06.047
P.23 Russian experience of DMD genetic database D. Vlodavets 1,2, D. Reshetov 1,2, S. Artemieva 1,2, E. Litvinova 1,2, I. Shulyakova 1,2, O. Shidlovskaya 1,2, D. Kazakov 1,2, E. Belousova 1,2 1 Veltischev Clinical Pediatric Research Institute of Pirogov Russian National Research Medical University, Moscow, Russia; 2 Marlin Biotech LLC, Moscow, Russia We present a genetic database of DMD and BMD patients of Russian neuromuscular center. At present, our DNA genetic database includes more than 180 patients from all over Russia. Primary cell cultures database consists of 100 samples. Our data include information about 174 DMD and 6 BMD boys. We still have 29 patients with clear DMD clinical manifestations with no genetic confirmation (they have been excluded from this analysis). From a recent cohort of 151 patients with proved mutations in DMD gene we detected 32 (21,2%) patients with different point mutations, 20 (13,2%) patients with exons duplications and 99 (65,6%) with different exons deletions. Only 55 (36,4%) patients could be treated with different exon skipping technologies. In theory, it is possible to treat about 50% of DMD patients by exon skipping technologies and about 10% could be treated by technologies correcting point STOP-mutations, both aimed to restore reading frame of DMD gene. 51 exon skipping technology could be relevant for 13% of DMD boys, skipping exons 45 and 53 – 8% for each, 44 – 6%, 52, 50 and 43 – 4%, 55 and 8 – 2% for each. In our cohort this theory was proven only in quantity of patients with STOPmutations only, which occurred in 15 (9,9%) patients. Exon skipping applicability in our cohort was: for 51 – 15 (9,9%) patients, for 45 – 12 (7,9%), for 53 – 6 (3,9%) patients, for 44 – 12 (7,9%) patients, for 52 – 5 (3,3%), for 55 – 2 (1,32%) patients, for 8 – 1 (0,66%) patient, and for 50, 43 and 17 no one. We continue to add patients in our database with the goal of being ready for the emergence of new drugs. In new era of targeted treatment of genetic disorders it is very important to collect information in databases. http://dx.doi.org/10.1016/j.nmd.2016.06.045
P.24 Genetic profile of Brazilian patients with dystrophinopathies L. Sauma, P. Ducceschi, C. Iwabe-Marchese, T. Rosa, A. Nucci, M. França Jr Universidade Estadual de Campinas-UNICAMP, Campinas, Brazil Duchenne (DMD) and Becker (BMD) muscular dystrophies are the most frequent myopathies in children and caused by mutations in the DMD gene.
S97
Little is known about the genetic profile of DMD/BMD in Brazilian patients. This information is important because mutation-specific genetic therapies are shortly coming. To characterize the genetic profile of Brazilian patients with DMD/BMD, we selected all patients with molecular diagnosis of dystrophinopathies followed at UNICAMP neuromuscular outpatient clinic between March 2015 and 2016. Each patient underwent molecular investigation that included MLPA and gene sequencing (small mutations). For those variants not previously reported, we looked at the available SNP and mutation databases (1000 genomes consortium, ExAC, NCBI and Ensembl) and also performed in silico analyses using different tools (Mutation taster, Polyphen2, Sift). We collected data on age at disease onset and duration and disease severity (using the MFM scale) in order to compare patients with large vs small mutations. We recruited 41 patients. Mean age at disease onset was 3.3 years (range 1–10); 19 patients were wheelchair users and 22 ambulant. Large deletions and duplications were found in 30 (73.2%) and point mutations in 9 (26.8%). In the later group, nonsense mutations were found in 3 patients from 2 unrelated families (7,3%) and frameshift mutations in 6 patients from 5 unrelated families (14.6%). We identify a novel intronic mutation (c.2803 + 5G > C) that was found in two brothers, one DMD other BMD phenotype. Genotype–phenotype analyses revealed no significant difference between patients with small vs large mutations in terms of disease progression and age at onset. Large deletions and duplications at the DMD gene are the most frequent genetic substrate in Brazilian patients. Small mutations were found in 26.8% of the patients. This profile is similar to that reported in European and North American cohorts. http://dx.doi.org/10.1016/j.nmd.2016.06.046
P.25 Variations in Duchenne muscular dystrophy clinical course in a multi-ethnic UK population: Are there potential influencing factors other than genetic modifiers? H. Roper, M. Hufton Birmingham Heartlands Hospital, Birmingham, UK Genetic modifiers have been identified as influencing disease course in Duchenne muscular dystrophy, particularly LTBP4 haplotype. In a single UK clinic population – serving a diverse multi-ethnic population with high levels of deprivation – we noted an apparent more severe clinical course in boys of south Asian ethnic origin and also an apparent tendency to refuse or defer steroid therapy. We explored these observations to see if they were borne out to indicate potentially modifiable factors. From 2005 to 2014, 71 children from 68 families were newly diagnosed with DMD. Their ethnic origin was white British 35, South Asian 23, white European 3, mixed heritage 7, other Asian 2, black African 1. Mean age at diagnosis (for those without known family history) was 45.5months; for white British 44.3 months (range 14–80) and for South Asians 50.2 months (range 5–98). 24 boys lost ambulation, 45 are still walking at age 4y5m – 15y9m (2 moved away). 10% of white British who had reached 9th birthday by the end of the study period had LOA whereas 53% of south Asian who had reached 9th birthday had LOA. Age starting steroids was similar in all groups; about 25% had a delay in starting steroids of >6 months; 17% of south Asians declined steroids compared to 10% white British. 47% of south Asians stopped steroids compared to 19% of white British. For the whole group, those most deprived – in the bottom 20% socioeconomically – did worse (none in the top 20% had LOA by 9y whereas 54% of the bottom 20% had LOA by 9y) but there was no difference in steroid usage and the more socially deprived 20% were diagnosed earlier and started steroids earlier. 64% of white British were in the lower 50% socioeconomically, compared to 71% of South Asians. 20% of white British were in the bottom 20% socioeconomically, compared to 47% of the South Asians. http://dx.doi.org/10.1016/j.nmd.2016.06.047