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Ozkinay F, Emecen DA, Kose M, Isik E, Bozaci AE, Canda E, Tuysuz B, Zubarioglu T, Atik T, Onay H. Clinical and genetic features of 13 patients with mucopolysaccarhidosis type IIIB: Description of two novel NAGLU gene mutations. Mol Genet Metab Rep 2021; 27:100732. [PMID: 33747789 PMCID: PMC7966861 DOI: 10.1016/j.ymgmr.2021.100732] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 11/25/2022] Open
Abstract
Aim Mucopolysaccharidosis type III B (MPS IIIB) is an autosomal recessive lysosomal storage disease caused by mutations in the NAGLU gene which codes the lysosomal enzyme alpha-N-acetylglucosaminidase. The major symptoms of the disease are cognitive and neurological defects. In this study, the molecular spectrums of 13 MPS IIIB patients were evaluated. Material and methods Thirteen MPS IIIB patients from 11 families were included in this study. All patients were both clinically and molecularly diagnosed. NAGLU gene sequencing was performed using a next generation sequencing platform (Illumina MiSeq). Demographic, clinical and laboratory findings of the patients were obtained via the hospital records. Results Ten different mutations from the 13 MPS IIIB patients were identified. Eight of the 10 mutations were missense, one was splice site, and one large deletion was also observed. Two mutations c.509G>T (p.Gly170Val) and c.700C>G (p.Arg234Gly) have been defined for the first time in this study. Conclusion Our study expanded the mutation spectrum of the NAGLU gene thereby contributing to the improved genetic counselling of MPS IIIB patients. Confirming the literature, missense mutations were also found to be the most common NAGLU mutations in our study.
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Affiliation(s)
- F Ozkinay
- Subdivision of Pediatric Genetics, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - D A Emecen
- Subdivision of Pediatric Genetics, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - M Kose
- Subdivision of Pediatric Genetics, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - E Isik
- Subdivision of Pediatric Genetics, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - A E Bozaci
- Subdivision of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - E Canda
- Subdivision of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - B Tuysuz
- Subdivision of Pediatric Genetics, Department of Pediatrics, Faculty of Medicine, Cerrahpasa University, Izmir, Turkey
| | - T Zubarioglu
- Subdivision of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Cerrahpasa University, Izmir, Turkey
| | - T Atik
- Subdivision of Pediatric Genetics, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - H Onay
- Department of Medical Genetics, Faculty of Medicine, Ege University, Izmir, Turkey
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Durmaz A, Aykut A, Atik T, Özen S, Ayyıldız Emecen D, Ata A, Işık E, Gökşen D, Çoğulu Ö, Özkınay F. A New Cause of Obesity Syndrome Associated with a Mutation in the Carboxypeptidase Gene Detected in Three Siblings with Obesity, Intellectual Disability and Hypogonadotropic Hypogonadism. J Clin Res Pediatr Endocrinol 2021; 13:52-60. [PMID: 32936766 PMCID: PMC7947731 DOI: 10.4274/jcrpe.galenos.2020.2020.0101] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Carboxypeptidase E (CPE) plays a critical role in the biosynthesis of peptide hormones and neuropeptides in the endocrine system and central nervous system. CPE knockout mice models exhibit disorders such as diabetes, hyperproinsulinaemia, low bone mineral density and neurodevelopmental disorders. Only one patient is described with morbid obesity, intellectual disability, abnormal glucose homeostasis and hypogonadotropic hypogonadism, which was associated with a homozygous frameshift deletion in CPE. METHODS Herein are described three siblings with obesity, intellectual disability and hypogonadotropic hypogonadism. Whole exome sequencing (WES) was performed in the index case. Candidate variants were prioritised and segregation of the variant, consistent with the phenotype of the index case, was assessed by Sanger sequencing in affected siblings and parents. RESULTS WES analysis revealed a homozygous nonsense c.405C>A (p.Y135*) mutation in CPE. Validation and segregation analysis confirmed the homozygous mutation in the index case and his affected siblings. The parents were phenotypically normal heterozygous mutation carriers. CONCLUSION This study provides additional evidence of the association between a homozygous nonsense mutation in CPE and a clinical phenotype consisting of obesity, intellectual disability and hypogonadotropic hypogonadism, which may be considered as a new monogenic obesity syndrome.
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Affiliation(s)
- Asude Durmaz
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey,* Address for Correspondence: Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey E-mail:
| | - Ayça Aykut
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey
| | - Tahir Atik
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Samim Özen
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Endocrinology, İzmir, Turkey
| | - Durdugül Ayyıldız Emecen
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Aysun Ata
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Endocrinology, İzmir, Turkey
| | - Esra Işık
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Damla Gökşen
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Endocrinology, İzmir, Turkey
| | - Özgür Çoğulu
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey,Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Ferda Özkınay
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey,Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
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