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Genotype-Phenotype Correlation and Follow-Up Features in Cases with Congenital Hyperinsulinism (CHI)

  • Samim Özen
  • Damla Gökşen
  • İlkin Mecidov
  • Sian Ellard
  • Özge Altun Köroğlu
  • Mehmet Yalaz
  • Şükran Darcan

J Clin Res Pediatr Endocrinol 2015;7(2):91-91

Introduction:

There is a genotype-phenotype correlation in cases with congenital hyperinsulinism (CHI). Genetic analysis that will be held in early stages is important for the treatment choice and follow-up of the patient. There have been 9 gene mutations defined in the genetic diagnosis of CHI. These are: K-ATP channel genes (ABCC8, KCNJ11), GLUD1, HADH, GCK, HNF4A, UCP2, SLC16A1 gene mutations.

Methods:

The follow-up data and the phenotypic and genotypic features of the 7 patients who were diagnosed with CHI between the years 2009 and 2014 were evaluated.

Results:

All our patients were diagnosed with hyperinsulinemic hypoglycemia in the first 48 hours. There was consanguinity between the parents of 4 patients (57%). Hyperinsulinism was temporary in 5 and permanent in 2 patients. Six cases were responsive to the diazoxide treatment, while one case was unresponsive and near total pancreatectomy was performed in the second month of its life. Motor-mental retardation and epilepsy occurred due to recurrent hypoglycemia and the patient developed post-op portal venous thrombosis. Mutations of the known genes were found in 3 of the patients (42.8%). A homozygote p.R1419C mutation in the ABCC8 gene of one diazoxide-responsive case with permanent CHI was detected. A diazoxide-responsive case with a heterozygous p.R365C mutation in the KCNJ11 gene and a case with a heterozygous p.R1539Q mutation in the ABCC8 gene showed remission in the 18th day and the 6th month respectively and the drugs were discontinued. The features of the cases are presented in the table.

Conclusion:

Genetic causes were detected in approximately 40% of our patients which is consistent with the literature. Other genes could play a role in cases without mutations.

Keywords: Congenital hyperinsulinism, genotype-phenotype correlation