Abstract
Maple syrup urine disease (MSUD) is a rare autosomal recessive metabolic disorder of branched-chain amino acid metabolism caused by the defective function of branched-chain α-ketoacid dehydrogenase complex (BCKDH). It is characterised by increased plasma leucine, isoleucine, and valine levels, and mutations can be detected in any one of the BCKDHA, BCKDHB, and DBT genes. In this study, we describe the molecular basis of a novel mutation found in one MSUD Malay patient from consanguineous parents. A homozygous mutation has been detected in this patient whose both parents carried a heterozygous mutation at DNA coding region c.431G>T in exon 4, which resulted in a substitution of serine to isoleucine at codon 144 (p.S144I). In silico analysis predicted S144I to be potentially damaging. The mutation was located on the alpha helical region of the BCKDHA protein, and it is predicted to affect the stability of protein due to the loss of various polar interactions between local secondary structures. Homology analysis revealed that this mutation occurred in a highly conserved region (100%). This result indicates that S144I mutation is likely pathogenic and may contribute to the classic form of MSUD in this patient.
We thank the Director General of Health Malaysia for permission to publish this paper. Our special thanks to Dr. Shahnaz Murad (Director of IMR) and Dr. Rohani Md Yasin (Centre Head, SDC) for critical reading of the manuscripts and valuable comments. We would like to extend our gratitude to Mohd Heikkal Ismail and Nurul Farahana Rosli for their excellent technical assistance and Mohd Khairul Nizam for his support in the protein structural analysis. We are also grateful to all clinicians for their contributions in this study. This study was funded by Diagnostics Services, Institute for Medical Research, Ministry of Health.
Conflict of interest statement
Competing interests: The authors declare that they have no competing interests.
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Articles in the same Issue
- Masthead
- Masthead
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- The relationship between adiposity and stature in prepubertal children with celiac disease
- Influence of micronutrient status and socioeconomic gradient on growth indices of 2–18-year-old Indian girls
- Phosphotyrosine phosphatases in GH-stimulated skin fibroblasts from children with idiopathic short stature
- The relation between salivary cortisol and the metabolic syndrome score in girls
- Association of vitamin D concentrations with adiposity indices among preadolescent children in Korea
- Association of serum resistin levels with metabolic syndrome and early atherosclerosis in obese Chinese children
- Characteristics of infants at risk of hypoglycaemia secondary to being ‘infant of a diabetic mother’
- Parental dyadic coping in families of children and adolescents with type 1 diabetes
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- Genetic diagnosis of one family with incomplete clinical data
- Patient reports
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- Gonadal function of beta-thalassemics following stem cell transplantation conditioned with myeloablative and reduced intensity regimens
- Significant testicular enlargement in a 6.5-year-old boy with monorchism and testicular microlithiasis
- Report of the first case of precocious puberty in Rett syndrome
- Type II vitamin D-dependent rickets with diabetic ketoacidosis
- Pituitary gigantism presenting with depressive mood disorder and diabetic ketoacidosis in an Asian adolescent
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