scholarly journals Maple syrup urine disease in Brazilian patients: variants and clinical phenotype heterogeneity

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
Adriana Aparecida Marques ◽  
...  

Abstract Background Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disease caused by deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by BCKDHA, BCKDHB, DBT, and DLD genes. MSUD is predominantly caused by Variants in BCKDHA, BCKDHB, and DBT genes encoding the E1α, E1β, and E2 subunits of BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD by identifying the point variants in BCKDHA, BCKDHB, and DBT genes in a cohort of Brazilian MSUD patients and to describe their phenotypic heterogeneity. It is a descriptive cross-sectional study with 21 MSUD patients involving molecular genotyping by Sanger sequencing. Results Eight new variants predicted as pathogenic were found between 30 variants (damaging and non-damaging) identified in the 21 patients analyzed: one in the BCKDHA gene (p.Tyr120Ter); five in the BCKDHB gene (p.Gly131Val, p.Glu146Glnfs * 13, p.Phe149Cysfs * 9, p.Cys207Phe, and p.Lys211Asn); and two in the DBT gene (p.Glu148Ter and p.Glu417Val). Seventeen pathogenic variants were previously described and five variants showed no pathogenicity according to in silico analysis. Conclusion Given that most of the patients received late diagnoses, the study results do not allow us to state that the molecular features of MSUD variant phenotypes are predictive of clinical severity.

2019 ◽  
Author(s):  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
Adriana Aparecida Marques ◽  
...  

Abstract Background: Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disease caused by deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by BCKDHA, BCKDHB, DBT, and DLD genes. MSUD is predominantly caused by Variants in BCKDHA, BCKDHB, and DBT genes encoding the E1α, E1β, and E2 subunits of BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD by identifying the point variants in BCKDHA, BCKDHB, and DBT genes in a cohort of Brazilian MSUD patients and to describe their phenotypic heterogeneity. It is a descriptive cross-sectional study with 21 MSUD patients involving PCR and sequencing. Results: Nine new variants predicted as pathogenic were found between 30 variants identified in the 21 patients analyzed: two in the BCKDHA gene (p.Gly56Arg, and p.Tyr120Ter); five in the BCKDHB gene (p.Gly131Val, p.Glu146Glnfs*13, p.Phe149Cysfs*9, p.Cys207Phe, and p.Lys211Asn); and two in the DBT gene (p.Glu148Ter and p.Glu417Val). Seventeen pathogenic variants were previously described and four variants showed no pathogenicity according to in silico analysis. Conclusion: Given that most of the patients received late diagnoses, the study results do not allow us to state that the molecular features of MSUD variant phenotypes are predictive of clinical severity.


2020 ◽  
Author(s):  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
Adriana Aparecida Marques ◽  
...  

Abstract Background: Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disease caused by deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by BCKDHA, BCKDHB, DBT, and DLD genes. MSUD is predominantly caused by Variants in BCKDHA, BCKDHB, and DBT genes encoding the E1α, E1β, and E2 subunits of BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD by identifying the point variants in BCKDHA, BCKDHB, and DBT genes in a cohort of Brazilian MSUD patients and to describe their phenotypic heterogeneity. It is a descriptive cross-sectional study with 21 MSUD patients involving molecular genotyping by Sanger sequencing. Results: Eight new variants predicted as pathogenic were found between 30 variants (damaging and non-damaging) identified in the 21 patients analyzed: one in the BCKDHA gene (p.Tyr120Ter); five in the BCKDHB gene (p.Gly131Val, p.Glu146Glnfs*13, p.Phe149Cysfs*9, p.Cys207Phe, and p.Lys211Asn); and two in the DBT gene (p.Glu148Ter and p.Glu417Val). Seventeen pathogenic variants were previously described and five variants showed no pathogenicity according to in silico analysis. Conclusion: Given that most of the patients received late diagnoses, the study results do not allow us to state that the molecular features of MSUD variant phenotypes are predictive of clinical severity.


2020 ◽  
Author(s):  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
Adriana Aparecida Marques ◽  
...  

Abstract Background: Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disease caused by deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by BCKDHA, BCKDHB, DBT, and DLD genes. MSUD is predominantly caused by Variants in BCKDHA, BCKDHB, and DBT genes encoding the E1α, E1β, and E2 subunits of BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD by identifying the point variants in BCKDHA, BCKDHB, and DBT genes in a cohort of Brazilian MSUD patients and to describe their phenotypic heterogeneity. It is a descriptive cross-sectional study with 21 MSUD patients involving molecular genotyping by Sanger sequencing. Results: Eight new variants predicted as pathogenic were found between 30 variants (damaging and non-damaging) identified in the 21 patients analyzed: one in the BCKDHA gene (p.Tyr120Ter); five in the BCKDHB gene (p.Gly131Val, p.Glu146Glnfs*13, p.Phe149Cysfs*9, p.Cys207Phe, and p.Lys211Asn); and two in the DBT gene (p.Glu148Ter and p.Glu417Val). Seventeen pathogenic variants were previously described and five variants showed no pathogenicity according to in silico analysis. Conclusion: Given that most of the patients received late diagnoses, the study results do not allow us to state that the molecular features of MSUD variant phenotypes are predictive of clinical severity.


2020 ◽  
Author(s):  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
Adriana Aparecida Marques ◽  
...  

Abstract Background: Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disease caused by deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by BCKDHA , BCKDHB , DBT , and DLD genes. MSUD is predominantly caused by Variants in BCKDHA , BCKDHB , and DBT genes encoding the E1α, E1β, and E2 subunits of BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD by identifying the point variants in BCKDHA , BCKDHB , and DBT genes in a cohort of Brazilian MSUD patients and to describe their phenotypic heterogeneity. It is a descriptive cross-sectional study with 21 MSUD patients involving PCR and sequencing. Results: Nine new variants predicted as pathogenic were found between 30 variants identified in the 21 patients analyzed: two in the BCKDHA gene (p.Gly56Arg, and p.Tyr120Ter); five in the BCKDHB gene (p.Gly131Val, p.Glu146Glnfs*13, p.Phe149Cysfs*9, p.Cys207Phe, and p.Lys211Asn); and two in the DBT gene (p.Glu148Ter and p.Glu417Val). Seventeen pathogenic variants were previously described and four variants showed no pathogenicity according to in silico analysis. Conclusion: Given that most of the patients received late diagnoses, the study results do not allow us to state that the molecular features of MSUD variant phenotypes are predictive of clinical severity. Keywords: inborn errors of metabolism; maple syrup urine disease; branched-chain amino acids; valine; leucine; isoleucine.


2020 ◽  
Author(s):  
Diana Ruffato Resende Campanholi ◽  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
...  

Abstract Background: Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disorder caused by the deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by four genes: BCKDHA, BCKDHB, DBT, and DLD. MSUD is predominantly caused by mutations in the BCKDHA, BCKDHB, and DBT genes which encode the E1α, E1β, and E2 subunits of the BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD in a cohort of Chilean MSUD patients by identifying point mutations in the BCKDHA, BCKDHB, and DBT genes and to describe their impact on the phenotypic heterogeneity of these patients. This manuscript describes a cross-sectional study of 18 MSUD patients carried out using PCR and DNA sequencing.Results: Four novel pathogenic mutations were identified: one in BCKDHA (p.Thr338Ile), two in BCKDHB (p.Gly336Ser e p.Pro240Thr), and one in DBT (p.Gly406Asp). Four additional pathogenic mutations found in this study have been described previously.Conclusion: There were no correlations between the genotype and phenotype of the patients. Thus, if MSUD is diagnosed earlier, with a neonatal screening approach, it might be possible to establish genotype-phenotype relationships more efficiently.


2019 ◽  
Author(s):  
Diana Ruffato Resende Campanholi ◽  
Ana Vitoria Barban Margutti ◽  
Wilson Araújo Silva ◽  
Daniel Fantozzi Garcia ◽  
Greice Andreotti de Molfetta ◽  
...  

Abstract Background: Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disease caused by deficient activity of the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. BCKD is a mitochondrial complex encoded by four genes: BCKDHA, BCKDHB, DBT, and DLD. MSUD is predominantly caused by mutations in the BCKDHA, BCKDHB, and DBT genes encoding the E1α, E1β, and E2 subunits of the BCKD complex, respectively. The aim of this study was to characterize the genetic basis of MSUD by identifying point mutations in the BCKDHA, BCKDHB, and DBT genes in a cohort of Chilean MSUD patients, and to describe their phenotypic heterogeneity. It is a descriptive cross-sectional study with 18 MSUD patients was carried out using PCR and DNA sequencing. Results: Four new pathogenic mutations were identified in the 18 patients that were analyzed: one in BCKDHA (p.Thr338Ile); two in BCKDHB (p.Gly336Ser e p.Pro240Thr); and one in DBT (p.Gly406Asp). Four additional pathogenic mutations found in the analyzed patients have been described previously. Conclusion: There were no correlations observed between genotypes and phenotypes. Thus, if MSUD is diagnosed more promptly, such as in neonatal screening, it might be possible to establish genotype-phenotype relationships more efficiently. Keywords: inborn errors of metabolism; maple syrup urine disease; branched-chain amino acids; valine; leucine; isoleucine.


2016 ◽  
Vol 32 (1) ◽  
pp. 105-113 ◽  
Author(s):  
Maryam Abiri ◽  
Razieh Karamzadeh ◽  
Marziyeh Mojbafan ◽  
Mohammad Reza Alaei ◽  
Atefeh Jodaki ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaohua Fang ◽  
Xiaofan Zhu ◽  
Yin Feng ◽  
Ying Bai ◽  
Xuechao Zhao ◽  
...  

AbstractMaple syrup urine disease (MSUD) is a rare autosomal recessive disorder that affects the degradation of branched chain amino acids (BCAAs). Only a few cases of MSUD have been documented in Mainland China. In this report, 8 patients (4 females and 4 males) with MSUD from 8 unrelated Chinese Han families were diagnosed at the age of 6 days to 4 months. All the coding regions and exon/intron boundaries of BCKDHA, BCDKHB, DBT and DLD genes were analyzed by targeted NGS in the 8 MSUD pedigrees. Targeted NGS revealed 2 pedigrees with MSUD Ia, 5 pedigrees with Ib, 1 pedigree with MSUD II. Totally, 13 variants were detected, including 2 variants (p.Ala216Val and p.Gly281Arg) in BCKDHA gene, 10 variants (p.Gly95Ala, p.Ser171Pro, p.Phe175Leu, p.Arg183Trp, p.Lys222Thr, p.Arg285Ter, p.Arg111Ter, p.S184Pfs*46, p.Arg170Cys, p.I160Ffs*25) in BCKDHB gene, 1 variant (p.Arg431Ter) in DBT gene. In addition, 4 previously unidentified variants (p.Gly281Arg in BCKDHA gene, p.Ser171Pro, p.Gly95Ala and p.Lys222Thr in BCKDHB gene) were identified. NGS plus Sanger sequencing detection is effective and accurate for gene diagnosis. Computational structural modeling indicated that these novel variations probably affect structural stability and considered as likely pathogenic variants.


2006 ◽  
Vol 37 (03) ◽  
Author(s):  
V Boda ◽  
S Vlaho ◽  
S Dittrich ◽  
M Baz Bartels ◽  
S Parbel ◽  
...  

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