title: Impact of Type 2 diabetes on Glucokinase diabetes (GCK-MODY) phenotype in a Roma (Gypsy) family - case report.
abstract: OBJECTIVE
  Glucokinase (GCK) diabetes is a mild form of the monogenic diabetes characterized by the fasting hyperglycemia without signs of metabolic syndrome and very low risk for chronic complications of diabetes. For the Type 2 diabetes (T2D), signs of the metabolic syndrome with high risk for chronic micro- and macro-vascular complications are typical. The prevalence of the GCK-diabetes is estimated from 0.5 to 1% in the diabetic patients. The T2D is the most prevalent type of the diabetes (it encompasses more than 85% of all the diabetic patients). According to the epidemiology, the coincidence of these two diabetes subtypes may occur; nevertheless no case reports on the above mentioned two diabetes subtypes have been published. The aim of the study was: 1) to perform the DNA analysis in three brothers, two of them with the fasting hyperglycemia and one with normal glucose tolerance, and their father with T2D metabolic syndrome and 2) to study the coincidence of the GCK-diabetes with T2D and its effect on the diabetic phenotype.
  
  
  METHODS
  We report about a Roma (Gypsy) family consisting of three brothers: 17 years old probant and two older brothers (21 and 25 years), and their father. The probant is suffering from fasting hyperglycemia. His 25 years old diabetic brother and their father suffer from obesity, hypertension, dyslipidemia, and hyperglycemia. The glucokinase gene was analyzed by direct sequencing in each of the brothers and their father, and appropriate phenotype characteristics were also carried out on each of the family members.
  
  
  RESULTS
  In the proband and his diabetic brother with the fasting hyperglycemia, a heterozygous mutation of the glucokinase gene p.Arg36Trp was found. The proband's phenotype was consistent with the GCK-diabetes, while the diabetic brother displayed already features of the metabolic syndrome. Although, the latter one suffered from the overweight, hypertension, and elevated triglycerides, his fasting hyperglycemia (8.3 mmol/l) was still consistent with the GCK-diabetes. Their father is also a heterozygous mutation carrier of the same mutation displaying all the features of the metabolic syndrome. In his case, the fasting hyperinsulinemia (43.5 μU/ml) and fasting plasma glucose (10.4 mmol/l) are more typical for the T2D than GCK-diabetes.
  
  
  CONCLUSIONS
  We found coincidence between the GCK-diabetes and T2D in the members of a single Roma (Gypsy) family. Since the chronic complications are rare in the GCK-diabetes, the major risk factor for the further morbidity may be in the development of the T2D. The overlapping of the GCK-diabetes with other types of diabetes, particularly the T2D, makes the diagnostics difficult and therefore, it might be one of the reasons why the estimated prevalence of the GCK-diabetes seems to be higher than the real one as it has been reported in several studies.
authors.affiliation: Slovak Academy of Science, Bratislava, Slovakia.
authors.forename: J
authors.initials: J
authors.lastname: Stanik
authors.forename: M
authors.initials: M
authors.lastname: Kusekova
authors.forename: M
authors.initials: M
authors.lastname: Huckova
authors.forename: L
authors.initials: L
authors.lastname: Valentinova
authors.forename: I
authors.initials: I
authors.lastname: Masindova
authors.forename: D
authors.initials: D
authors.lastname: Stanikova
authors.forename: J
authors.initials: J
authors.lastname: Ferenczova
authors.forename: D
authors.initials: D
authors.lastname: Gasperikova
authors.forename: I
authors.initials: I
authors.lastname: Klimes
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology* / Q000235:genetics*; D005192:Family Health; D005260:Female; D005838:Genotype; D005941:Glucokinase / Q000235:genetics*; D006801:Humans; D008297:Male; D010375:Pedigree; D010641:Phenotype; D015995:Prevalence; D012307:Risk Factors; D006178:Romani People / Q000235:genetics* / Q000706:statistics & numerical data*; D018154:Slovakia; D055815:Young Adult
chemical_list: D005941:Glucokinase