Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients

Objective. To characterize the genotype and phenotype of Chinese patients with congenital hyperinsulinism (CHI) caused by activating mutations in GLUD1, the gene that encodes mitochondrial enzyme glutamate dehydrogenase (GDH). Methods. The clinical data of glutamate dehydrogenase hyperinsulinism (GD...

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Main Authors: Chang Su, Xue-Jun Liang, Wen-Jing Li, Di Wu, Min Liu, Bing-Yan Cao, Jia-Jia Chen, Miao Qin, Xi Meng, Chun-Xiu Gong
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:Journal of Diabetes Research
Online Access:http://dx.doi.org/10.1155/2018/2802540
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author Chang Su
Xue-Jun Liang
Wen-Jing Li
Di Wu
Min Liu
Bing-Yan Cao
Jia-Jia Chen
Miao Qin
Xi Meng
Chun-Xiu Gong
author_facet Chang Su
Xue-Jun Liang
Wen-Jing Li
Di Wu
Min Liu
Bing-Yan Cao
Jia-Jia Chen
Miao Qin
Xi Meng
Chun-Xiu Gong
author_sort Chang Su
collection DOAJ
description Objective. To characterize the genotype and phenotype of Chinese patients with congenital hyperinsulinism (CHI) caused by activating mutations in GLUD1, the gene that encodes mitochondrial enzyme glutamate dehydrogenase (GDH). Methods. The clinical data of glutamate dehydrogenase hyperinsulinism (GDH-HI) patients were reviewed, and gene mutations were confirmed by whole exome sequencing (WES) and Sanger DNA sequencing. Results. Twenty-six patients with GDH-HI heterozygous missense mutations were identified from 240 patients diagnosed as congenital hyperinsulinism over past 15 years. The median age at onset was 8 months (range: 1 day of life to 3 years). Seizure disorder was common in our cohort of patients (23/26). Four patients had normal serum ammonia levels; the median serum concentration was 101 μmol/L (range: 37–190 μmol/L). Hypoglycemic symptoms could be triggered by fasting or protein meals in all patients while blood glucose could be well controlled in all patients with diazoxide. Dosage of diazoxide could be reduced by protein restriction. Attempts to lower ammonia levels failed with different therapies such as protein restriction, benzoate, or N-carbamoyl glutamate. In follow-up, 15 of 26 patients had normal intelligence. Eleven patients developed epilepsy at the age of 6 months to 11 years. De novo mutations in GLUD1 were found in 24 cases, and dominant inheritance was observed in the other two; all were heterozygous. A total of 35% (9/26) patients carried c.1493C>T (p.S445L) mutation. Conclusions. Phenotypic heterogeneity of GDH-HI patients was observed within the Chinese cohort in the present study. The fact that most patients had a GLUD1 p. S445L mutation implies that this site could be a hotspot in Chinese patients. A high frequency of GDH-HI with normal ammonia has been reported in this study. Hence, GLUD1 mutational analysis may be an important method to differential diagnosis of GDH-HI from other diazoxide-responsive CHI in Chinese patients.
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spelling doaj-art-e73595bea4594365aabb5abf2c2d5fcd2025-08-20T03:26:14ZengWileyJournal of Diabetes Research2314-67452314-67532018-01-01201810.1155/2018/28025402802540Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia PatientsChang Su0Xue-Jun Liang1Wen-Jing Li2Di Wu3Min Liu4Bing-Yan Cao5Jia-Jia Chen6Miao Qin7Xi Meng8Chun-Xiu Gong9Department of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaDepartment of Pediatric Endocrinology, Genetic and Metabolism, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, ChinaObjective. To characterize the genotype and phenotype of Chinese patients with congenital hyperinsulinism (CHI) caused by activating mutations in GLUD1, the gene that encodes mitochondrial enzyme glutamate dehydrogenase (GDH). Methods. The clinical data of glutamate dehydrogenase hyperinsulinism (GDH-HI) patients were reviewed, and gene mutations were confirmed by whole exome sequencing (WES) and Sanger DNA sequencing. Results. Twenty-six patients with GDH-HI heterozygous missense mutations were identified from 240 patients diagnosed as congenital hyperinsulinism over past 15 years. The median age at onset was 8 months (range: 1 day of life to 3 years). Seizure disorder was common in our cohort of patients (23/26). Four patients had normal serum ammonia levels; the median serum concentration was 101 μmol/L (range: 37–190 μmol/L). Hypoglycemic symptoms could be triggered by fasting or protein meals in all patients while blood glucose could be well controlled in all patients with diazoxide. Dosage of diazoxide could be reduced by protein restriction. Attempts to lower ammonia levels failed with different therapies such as protein restriction, benzoate, or N-carbamoyl glutamate. In follow-up, 15 of 26 patients had normal intelligence. Eleven patients developed epilepsy at the age of 6 months to 11 years. De novo mutations in GLUD1 were found in 24 cases, and dominant inheritance was observed in the other two; all were heterozygous. A total of 35% (9/26) patients carried c.1493C>T (p.S445L) mutation. Conclusions. Phenotypic heterogeneity of GDH-HI patients was observed within the Chinese cohort in the present study. The fact that most patients had a GLUD1 p. S445L mutation implies that this site could be a hotspot in Chinese patients. A high frequency of GDH-HI with normal ammonia has been reported in this study. Hence, GLUD1 mutational analysis may be an important method to differential diagnosis of GDH-HI from other diazoxide-responsive CHI in Chinese patients.http://dx.doi.org/10.1155/2018/2802540
spellingShingle Chang Su
Xue-Jun Liang
Wen-Jing Li
Di Wu
Min Liu
Bing-Yan Cao
Jia-Jia Chen
Miao Qin
Xi Meng
Chun-Xiu Gong
Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients
Journal of Diabetes Research
title Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients
title_full Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients
title_fullStr Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients
title_full_unstemmed Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients
title_short Clinical and Molecular Spectrum of Glutamate Dehydrogenase Gene Defects in 26 Chinese Congenital Hyperinsulinemia Patients
title_sort clinical and molecular spectrum of glutamate dehydrogenase gene defects in 26 chinese congenital hyperinsulinemia patients
url http://dx.doi.org/10.1155/2018/2802540
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