Novel mutations associated with nephrogenic diabetes insipidus. A clinical-genetic study.

UNLABELLED: Molecular diagnosis is a useful diagnostic tool in primary nephrogenic diabetes insipidus (NDI), an inherited disease characterized by renal inability to concentrate urine. The AVPR2 and AQP2 genes were screened for mutations in a cohort of 25 patients with clinical diagnosis of NDI. Patients presented with dehydration, polyuria-polydipsia, failure to thrive (mean ± SD; Z-height -1.9 ± 2.1 and Z-weight -2.4 ± 1.7), severe hypernatremia (mean ± SD; Na 150 ± 10 mEq/L), increased plasma osmolality (mean ± SD; 311 ± 18 mOsm/Kg), but normal glomerular filtration rate. Genetic diagnosis revealed that 24 male patients were hemizygous for 17 different putative disease-causing mutations in the AVPR2 gene (each one in a different family). Of those, nine had not been previously reported, and eight were recurrent. Moreover, we found those same AVPR2 changes in 12 relatives who were heterozygous carriers. Further, in one female patient, AVPR2 gene study turned out to be negative and she was found to be homozygous for the novel AQP2 p.Ala86Val alteration. CONCLUSION: Genetic analysis presumably confirmed the diagnosis of nephrogenic diabetes insipidus in every patient of the studied cohort. We emphasize that we detected a high presence (50 %) of heterozygous females with clinical NDI symptoms. WHAT IS KNOWN: • In most cases (90 %), inherited nephrogenic diabetes insipidus (NDI) is an X-linked disease, caused by mutations in the AVPR2 gene. • In rare occasions (10 %), it is caused by mutations in the AQP2 gene. What is new: • In this study, we report 10 novel mutations associated with NDI. • We have detected a high presence (50 %) of heterozygous carriers with clinical NDI symptoms.

[Triponderal mass index and markers of metabolic risk in children and adolescents with obesity]. / Índice de masa triponderal y marcadores de riesgo metabólico en niños y adolescentes con obesidad.

BACKGROUND AND OBJECTIVE: Triponderal mass index (TMI) would estimate excess adiposity better than body mass index (BMI), maintaining stable values during childhood. This work aims to determine the correlation between TMI and markers of metabolic risk as well as set values of TMI that are related to an increase of metabolic risk. MATERIAL AND METHODS: Multicenter, observational, cross-sectional and prospective study in children under 14 years of age with obesity. VARIABLES: age, sex, pubertal stage, weight, height, abdominal circumference, BMI, TMI, basal glucose and insulin, HOMA index, blood pressure, lipoprotein profile, transaminases and uric acid. BMI and TMI were expressed according to the values of the Barcelona longitudinal study. Statistical analysis was performed with the SPSS* program. RESULTS: One hundred and ninety-nine patients (50.3% male), age 11.08 (2.48) years, TMI 19.68 (2.36)kg/m3. Correlation between TMI and abdominal circumference (r=0.571; p=0), insulin (r=0.198; p=0.005), HOMA index (r=0.189; p=0.008) and HDL-c (r=-0.188; p=0.008) was observed. IMT>20.15kg/m3 was associated with insulin≥15mIU/ml (p=0.029) and IMT>20.36kg/m3 with HDL-c<40mg/dl (p=0.023). CONCLUSIONS: TMI was correlated with increase of abdominal circumference, insulin and HOMA index and decrease of HDL-c. IMT>20kg/m3 can be associated with increased insulin and decreased HDL-c. Therefore, the IMT seems to be a useful parameter in the assessment of pediatric patients with obesity.

[Estimated glucose disposal rate in patients under 18 years of age with type 1 diabetes mellitus and overweight or obesity]. / Tasa estimada de disposición de glucosa en pacientes menores de 18 años con diabetes mellitus tipo 1 y sobrepeso-obesidad.

OBJECTIVE: To assess the estimated glucose disposal rate (eGDR), insulin dose, and lipoprotein profile in children with type 1 diabetes mellitus (T1DM) and overweight or obesity as compared to children with T1DM and normal weight. METHODS: A total of 115 patients (aged 5-16 years) with T1DM on intensive insulin therapy were recruited. The following parameters were measured: weight, height, body mass index, waist and hip circumference, insulin dose, eGDR, glycosylated hemoglobin, blood pressure, and lipoprotein profile. Results were stratified by sex and age. RESULTS: No significant differences were found in eGDR between children with normal weight, overweight, and obesity. However, obese children older than 11 years had lower eGDR values (9.3±1.3 vs 10.1±0.8 mg kg(-1)min(-1); p<0.01). Insulin dose was higher in overweight and obese children, especially in IU/m2/day (37.7 vs 36.1 vs. 29.4 respectively; p<0.01). Obese children had higher low-density lipoprotein cholesterol levels than children with overweight and normal weight (106.5 vs 91.7 vs 91.5mg/dL respectively; p<0.01). No correlation was found between waist circumference and the different markers of insulin resistance. CONCLUSIONS: Values of eGDR values were lower in obese children with T1DM older than 11 years, and this may therefore be considered a marker of insulin resistance. Insulin dose was higher in diabetic patients with overweight or obesity, specially in IU/m2/day. Obese children with T1DM had a lipoprotein profile of cardiovascular risk.