Genetic variability of GCKR alters lipid profiles in children with monogenic and autoimmune diabetes.

PURPOSE: Mutations in the glucokinase (GCK) gene are associated with altered blood glucose and lipid concentrations. Our aim was to assess the effects on HbA1c and serum lipid levels of single nucleotide polymorphisms (SNPs) in 2 genes encoding proteins that interact with glucokinase: glucose-6-phospatase catalytic subunit 2 (G6PC2) and glucokinase regulatory protein (GCKR). METHODS: The study group included 129 children with GCK-MODY from the Polish Registry of Monogenic Diabetes and 395 with type 1 diabetes (T1DM), in whom we genotyped 2 SNPs in G6PC2 (rs560887) and GCKR (rs1260326). Lipid concentrations were assessed in fasting serum samples. RESULTS: Total and HDL cholesterol concentrations were significantly lower in the GCK-MODY group than in patients with T1DM (167.5±32.5 mg/dl vs. 174.4±31.1 mg/dl, p=0.0435 and 48.42±14.3 mg/dl vs. 58.7±12.7 mg/dl, p<0.0001, respectively). No differences in genotype distributions were found except for underrepresentation of GCKR TT homozygotes among GCK-MODY patients (10.9% in GCK-MODY vs. 17.7% in T1DM, p=0.0651). GCKR genotypes showed significant associations with lipid profiles and HbA1c levels, whereas no such associations were noted for G6PC2. After adjustment for confounders, TT homozygotes were shown to have higher total cholesterol and marginally higher LDL cholesterol and triglyceride levels (p=0.0245, p=0.0657 and p=0.0550, respectively). The difference between TT homozygotes and other genotypes was similar in magnitude within the GCK-MODY and T1DM groups. No significant interactions between the type of diabetes and the GCKR or G6PC2 genotype were detected. CONCLUSIONS: Individuals who are homozygous TT at rs1260326 of the GCKR gene have higher triglyceride, total and LDL cholesterol levels regardless of the presence of GCK mutations.

Doubling the referral rate of monogenic diabetes through a nationwide information campaign--update on glucokinase gene mutations in a Polish cohort.

In order to improve recruitment efficiency of patients with monogenic diabetes in Poland, in September 2010 a nationwide advertising campaign was launched to inform multiple target groups interested or participating in pediatric diabetologic care. Promotional actions aimed at informing physicians, patients, parents and educators were carried out through nationwide newspapers, medical and patient-developed websites and educational conference presentations. Recruitment efficiency was compared between September 2010 (publication of the first report on project's results) and the following 12 months. The number of families and patients referred to genetic screening was increased by 92% and 96% respectively nearly reaching the numbers recruited throughout the initial 4 years of the project. Participation of non-academic centers was also significantly increased from 2.3% to 7.5% (p = 0.0005). DNA sequencing and Multiplex Ligation-dependant Probe Amplification of the glucokinase gene resulted in finding 50 different mutations. Among those mutations, 19 were novel variants, which included: 17 missense mutations (predicted to be pathogenic according to bioinformatic analysis), 1 nonsense mutation and 1 mutation affecting a consensus intronic splice site. Advertising actions directed at increasing recruitment efficiency are a powerful and possibly neglected tool in screening for rare genetic disorders with a clinically defined phenotype.