5-Fluorouracil Induced Hypertriglyceridemia During the Colorectal Cancer Treatment in a Patient With Multifactorial Chylomicronemia Syndrome: A Case Report.

PURPOSE: The case of a 47-year-old female patient who underwent sigmoidectomy for metastatic colorectal cancer is reported. Treatment with capecitabine and 5-fluorouracil induced severe hypertriglyceridemia repeatedly. METHODS: Based on laboratory tests and clinical evaluations, treatment was suggested by specialists. FINDINGS: After treatment with capecitabine, the patient's triglycerides increased from 19.7 mmol/L to 42 mmol/L. It was proposed that the patient had multifactorial chylomicronemia syndrome triggered by secondary factors. Statins, fenofibrate, ezetimib, and metformin were added to the therapy. After metastases appeared, FOLFIRI (leucovorin calcium [folinic acid], 5-fluorouracil, and irinotecan hydrochloride) chemotherapy and biological treatment (cetuximab) followed and triglycerides increased to 55.3 mmol/L. IMPLICATIONS: Monitoring triglyceride levels before and during therapy is suggested.

Genetic analysis of single-minded 1 gene in early-onset severely obese children and adolescents.

BACKGROUND: Inactivating mutations of the hypothalamic transcription factor singleminded1 (SIM1) have been shown as a cause of early-onset severe obesity. However, to date, the contribution of SIM1 mutations to the obesity phenotype has only been studied in a few populations. In this study, we screened the functional regions of SIM1 in severely obese children of Slovak and Moravian descent to determine if genetic variants within SIM1 may influence the development of obesity in these populations. METHODS: The SIM1 promoter region, exons and exon-intron boundaries were sequenced in 126 unrelated obese children and adolescents (2-18 years of age) and 41 adult lean controls of Slovak and Moravian origin. Inclusion criteria for the children and adolescents were a body mass index standard deviation score higher than 2 SD for an appropriate age and sex, and obesity onset at less than 5 years of age. The clinical phenotypes of the SIM1 variant carriers were compared with clinical phenotypes of 4 MC4R variant carriers and with 27 unrelated SIM1 and MC4R mutation negative obese controls that were matched for age and gender. RESULTS: Seven previously described SIM1 variants and one novel heterozygous variant p.D134N were identified. The novel variant was predicted to be pathogenic by 7 in silico software analyses and is located at a highly conserved position of the SIM1 protein. The p.D134N variant was found in an 18 year old female proband (BMI 44.2kg/m2; +7.5 SD), and in 3 obese family members. Regardless of early onset severe obesity, the proband and her brother (age 16 years) did not fulfill the criteria of metabolic syndrome. Moreover, the variant carriers had significantly lower preferences for high sugar (p = 0.02) and low fat, low carbohydrate, high protein (p = 0.02) foods compared to the obese controls. CONCLUSIONS: We have identified a novel SIM1 variant, p.D134N, in 4 obese individuals from a single pedigree which is also associated with lower preference for certain foods.

Genetic testing of familial hypercholesterolemia in a real clinical setting.

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder characterized by strikingly elevated low-density lipoprotein (LDL) cholesterol levels and premature atherosclerosis. For individuals with a definite or probable diagnosis of FH, molecular genetic testing is recommended. This can be justified in countries where genetic testing is broadly available and covered. On the other hand, in countries with limited access to genetic testing, it can be argued whether it is necessary and cost-effective to perform genetic testing in patients with a proven clinical diagnosis of FH. This article presents a family with FH where different family members manifested different phenotypes and discusses situations where genetic diagnosis can crucially help physicians in clinical decision-making on how to approach and treat patients.

De novo mutations of GCK, HNF1A and HNF4A may be more frequent in MODY than previously assumed.

AIMS/HYPOTHESIS: MODY is mainly characterised by an early onset of diabetes and a positive family history of diabetes with an autosomal dominant mode of inheritance. However, de novo mutations have been reported anecdotally. The aim of this study was to systematically revisit a large collection of MODY patients to determine the minimum prevalence of de novo mutations in the most prevalent MODY genes (i.e. GCK, HNF1A, HNF4A). METHODS: Analysis of 922 patients from two national MODY centres (Slovakia and the Czech Republic) identified 150 probands (16%) who came from pedigrees that did not fulfil the criterion of two generations with diabetes but did fulfil the remaining criteria. The GCK, HNF1A and HNF4A genes were analysed by direct sequencing. RESULTS: Mutations in GCK, HNF1A or HNF4A genes were detected in 58 of 150 individuals. Parents of 28 probands were unavailable for further analysis, and in 19 probands the mutation was inherited from an asymptomatic parent. In 11 probands the mutations arose de novo. CONCLUSIONS/INTERPRETATION: In our cohort of MODY patients from two national centres the de novo mutations in GCK, HNF1A and HNF4A were present in 7.3% of the 150 families without a history of diabetes and 1.2% of all of the referrals for MODY testing. This is the largest collection of de novo MODY mutations to date, and our findings indicate a much higher frequency of de novo mutations than previously assumed. Therefore, genetic testing of MODY could be considered for carefully selected individuals without a family history of diabetes.

Identification and functional characterisation of novel glucokinase mutations causing maturity-onset diabetes of the young in Slovakia.

Heterozygous glucokinase (GCK) mutations cause a subtype of maturity-onset diabetes of the young (GCK-MODY). Over 600 GCK mutations have been reported of which ∼65% are missense. In many cases co-segregation has not been established and despite the importance of functional studies in ascribing pathogenicity for missense variants these have only been performed for <10% of mutations. The aim of this study was to determine the minimum prevalence of GCK-MODY amongst diabetic subjects in Slovakia by sequencing GCK in 100 Slovakian probands with a phenotype consistent with GCK-MODY and to explore the pathogenicity of identified variants through family and functional studies. Twenty-two mutations were identified in 36 families (17 missense) of which 7 (I110N, V200A, N204D, G258R, F419S, c.580-2A>C, c.1113-1114delGC) were novel. Parental DNA was available for 22 probands (covering 14/22 mutations) and co-segregation established in all cases. Bioinformatic analysis predicted all missense mutations to be damaging. Nine (I110N, V200A, N204D, G223S, G258R, F419S, V244G, L315H, I436N) mutations were functionally evaluated. Basic kinetic analysis explained pathogenicity for 7 mutants which showed reduced glucokinase activity with relative activity indices (RAI) between 0.6 to <0.001 compared to wild-type GCK (1.0). For the remaining 2 mutants additional molecular mechanisms were investigated. Differences in glucokinase regulatory protein (GKRP) -mediated-inhibition of GCK were observed for both L315H & I436N when compared to wild type (IC(50) 14.6±0.1 mM & 20.3±1.6 mM vs.13.3±0.1 mM respectively [p<0.03]). Protein instability as assessed by thermal lability studies demonstrated that both L315H and I436N show marked thermal instability compared to wild-type GCK (RAI at 55°C 8.8±0.8% & 3.1±0.4% vs. 42.5±3.9% respectively [p<0.001]). The minimum prevalence of GCK-MODY amongst Slovakian patients with diabetes was 0.03%. In conclusion, we have identified 22 GCK mutations in 36 Slovakian probands and demonstrate that combining family, bioinformatic and functional studies can aid the interpretation of variants identified by molecular diagnostic screening.

Identification of a novel beta-cell glucokinase (GCK) promoter mutation (-71G>C) that modulates GCK gene expression through loss of allele-specific Sp1 binding causing mild fasting hyperglycemia in humans.

OBJECTIVE: Inactivating mutations in glucokinase (GCK) cause mild fasting hyperglycemia. Identification of a GCK mutation has implications for treatment and prognosis; therefore, it is important to identify these individuals. A significant number of patients have a phenotype suggesting a defect in glucokinase but no abnormality of GCK. We hypothesized that the GCK beta-cell promoter region, which currently is not routinely screened, could contain pathogenic mutations; therefore, we sequenced this region in 60 such probands. RESEARCH DESIGN AND METHODS: The beta-cell GCK promoter was sequenced in patient DNA. The effect of the identified novel mutation on GCK promoter activity was assessed using a luciferase reporter gene expression system. Electrophoretic mobility shift assays (EMSAs) were used to determine the impact of the mutation on Sp1 binding. RESULTS: A novel -71G>C mutation was identified in a nonconserved region of the human promoter sequence in six apparently unrelated probands. Family testing established cosegregation with fasting hyperglycemia (> or = 5.5 mmol/l) in 39 affected individuals. Haplotype analysis in the U.K. family and four of the Slovakian families demonstrated that the mutation had arisen independently. The mutation maps to a potential transcriptional activator binding site for Sp1. Reporter assays demonstrated that the mutation reduces promoter activity by up to fourfold. EMSAs demonstrated a dramatic reduction in Sp1 binding to the promoter sequence corresponding to the mutant allele. CONCLUSIONS: A novel beta-cell GCK promoter mutation was identified that significantly reduces gene expression in vitro through loss of regulation by Sp1. To ensure correct diagnosis of potential GCK-MODY (maturity-onset diabetes of the young) cases, analysis of the beta-cell GCK promoter should be included.

Lower adrenocortical and adrenomedullary responses to hypoglycemia in premenopausal women with systemic sclerosis.

OBJECTIVES: To evaluate function of the hypothalamic-pituitary-adrenal (HPA) axis, adrenomedullary hormonal system (AMHS), and sympathetic noradrenergic system (SNS) in premenopausal women with systemic sclerosis (SSc). METHODS: Insulin-induced hypoglycemia (0.1 IU/kg) was performed in 17 longterm, glucocorticoid-naive SSc patients with low disease activity and in 18 healthy women matched for age and body mass index (BMI). Concentrations of glucose, adrenocorticotrophic hormone (ACTH), cortisol, androstenedione (ASD), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), 17a-hydroxyprogesterone (17OHP), epinephrine (EPI), norepinephrine (NE), interleukin 1ss (IL-1ss), IL-6, and tumor necrosis factor-a (TNF-a) were analyzed in plasma. RESULTS: Basal plasma levels of cortisol, ASD, 17OHP, DHEAS, IL-1ss, IL-6, and TNF-a were not significantly different in SSc compared to controls. Patients had higher basal ACTH (6.76 +/- 1.0 pmol/l in SSc vs 4.14 +/- 0.45 pmol/l in controls; p < 0.05), lower basal DHEA (9.02 +/- 1.64 nmol/l in SSc vs 17.0 +/- 2.8 nmol/l in controls; p < 0.05), and lower basal NE (1.61 +/- 0.26 nmol/l in SSc vs 2.57 +/- 0.38 nmol/l in controls; p < 0.05). Patients had comparable responses of glucose and ACTH to hypoglycemia. General linear model for repeated measurements, with BMI and age as covariates, revealed that the responses of 17OHP (p < 0.05), ASD (p < 0.05), DHEA (p < 0.01), EPI (p < 0.001), and NE (p < 0.001) to hypoglycemia were lower in SSc compared to controls. Cortisol response to hypoglycemia tended to be lower in SSc patients (p = 0.06) compared to controls. CONCLUSION: Our data indicate decreased adrenocortical and adrenomedullary functions in premenopausal women with SSc. Whether the observed changes in the neuroendocrine system are secondary to chronic disease deserves further investigation.