Variants of STAR, AMH and ZFPM2/FOG2 May Contribute towards the Broad Phenotype Observed in 46,XY DSD Patients with Heterozygous Variants of NR5A1.

Variants of NR5A1 are often found in individuals with 46,XY disorders of sex development (DSD) and manifest with a very broad spectrum of clinical characteristics and variable sex hormone levels. Such complex phenotypic expression can be due to the inheritance of additional genetic hits in DSD-associated genes that modify sex determination, differentiation and organ function in patients with heterozygous NR5A1 variants. Here we describe the clinical, biochemical and genetic features of a series of seven patients harboring monoallelic variants in the NR5A1 gene. We tested the transactivation activity of novel NR5A1 variants. We additionally included six of these patients in a targeted diagnostic gene panel for DSD and identified a second genetic hit in known DSD-causing genes STAR, AMH and ZFPM2/FOG2 in three individuals. Our study increases the number of NR5A1 variants related to 46,XY DSD and supports the hypothesis that a digenic mode of inheritance may contribute towards the broad spectrum of phenotypes observed in individuals with a heterozygous NR5A1 variation.

For Debate: Paediatric T1DM: DKA is Still a Problem.

Although the treatment of pediatric patients with T1DM has improved ketoacidosis (DKA) remains a frequent problem. OBJECTIVE: To estimate temporal changes in the prevalence of DKA at diagnosis of T1DM and to explore the factors associated with its occurrence. METHODS: Paediatric patients diagnosed at Cruces University Hospital (Spain) since 1997 were included. Clinical/analytical variables at diabetes onset, Hemoglobin A1c level during the first 2 years of evolution and the presence of the honeymoon phase were studied. RESULTS: In 209 patients the prevalence of DKA was stable over time and high (35.4%) especially in the youngest. 8.5% of patients had a severe DKA with a higher risk in older than 10. Partial remission occurred in 26% patients, less frequent in the youngest and in the subgroup with DKA at diagnosis. CONCLUSION: The frequency of DKA although stable, remains high and is associated with a worse evolution of the disease.

Heterogeneity in phenotype of hyperinsulinism caused by activating glucokinase mutations: a novel mutation and its functional characterization.

BACKGROUND: Mutations in the GCK gene lead to different forms of glucokinase (GCK)-disease, activating mutations cause hyperinsulinaemic hypoglycaemia while inactivating mutations cause monogenic diabetes. Hyperinsulinism (HI) is a heterogeneous condition with a significant genetic component. The major causes are channelopathies, the other forms are rare and being caused by mutations in genes such as GCK. OBJECTIVE: To describe the clinical and genetic presentation of four families with activating GCK mutations, and to explore the pathogenicity of the novel mutation identified through functional studies. RESULTS: Four cases of HI with mutations in GCK were identified. These include one novel mutation (p.Trp99Cys). Functional analysis of the purified mutant fusion protein glutathione-S-transferase (GST)-GCK-p.Trp99Cys demonstrated that p.Trp99Cys is an activating mutation as it induces a higher affinity for glucose and increases the relative activity index more than 11 times. Moreover, the thermal stability of the mutant protein was similar to that of its wild type. All patients were responsive to diazoxide treatment. One of the mutations arose de novo, and two were dominantly inherited, although only one of them from an HI affected parent. The age of presentation in our cases varied widely from the neonatal period to adulthood. CONCLUSION: The clinical phenotype of the GCK activating mutation carriers was heterogeneous, the severity of symptoms and age at presentation varied markedly between affected individuals, even within the same family. The novel activating GCK mutation (p.Trp99Cys) has a strong activating effect in vitro although it has been identified in one case of a milder and late-onset form of HI.

Incidence of childhood-onset type 1 diabetes in Biscay, Spain, 1990-2013.

OBJECTIVE: To identify the incidence rate (IR) and epidemiologic trends of childhood type 1 diabetes mellitus (T1DM) in children aged 0 to 14-yr-old from 1990 to 2013, in the north of Spain (Biscay). SUBJECTS AND METHODS: A prospective-retrospective study was performed. Capture-recapture method was used: primary cases were ascertained from hospital register and a secondary independent data source was obtained from diabetes associations and public health plan database. Age and sex-standardized incidence rates were calculated using direct method, assuming an equal distribution in each age/sex group. In order to identify and analyse trends the period studied was divided into two (1990-2001 and 2002-2013) 11-year periods. The 95% confidence interval (CI) was estimated assuming the Poisson distribution. RESULTS: A total of 399 new cases were identified throughout the study. Mean age at diagnosis was 8.9 ± 3.7 yr. Completeness of ascertainment was 99.1%. Mean annual age-standardized IR was 10.7 (95% CI: 9.6-11.7). The mean incidence for the 0-4, 5-9 and 10-14 age groups was 5.1, 14.6 and 13.2 per 100,000 children/yr, respectively. The incidence rate trend in the whole group was not statistically significant. In the 10-14 age group we found a yearly average increase (2.5% [CI 95% 0.4-4.6]; P < 0.05) and analysing by sex, this statistically significant incidence trend was observed only in boys. We did not find a seasonal onset pattern. CONCLUSIONS: The IR did not increase in this population during the period studied unlike the results in other Spanish regions and European Countries.

Absence of diabetes mellitus type 2 in obese children and adolescents in the north of Spain.

BACKGROUND: The worldwide epidemic of childhood obesity has been accompanied by an increase in the incidence of carbohydrate metabolism disorders. OBJECTIVE: To determine the prevalence of type 2 diabetes mellitus (T2DM) and other carbohydrate metabolism disorders in obese young people in the Basque Country (Spain). DESIGN: Prospective observational study. PATIENTS: We studied 136 obese Caucasian children and adolescents (body mass index ≥2 SDS above the mean). MEASUREMENTS: Their severity of obesity was classified as mild <3 SDS or moderate-to-severe ≥3 SDS. Data were collected on clinical and metabolic parameters; insulin resistance (IR) was calculated using the homeostasis model assessment, and an oral glucose tolerance test (OGTT) was carried out. RESULTS: T2DM was not found. Impaired glucose tolerance (IGT) was found in 9.6% of patients being higher in moderate-to-severe obesity (12.8% vs. 2.4%; p=0.048) and in patients with acanthosis nigricans (27.8% vs. 6.8%; p=0.016). No differences were detected by sex or pubertal development in metabolic results as a function of OGTT's response. IR (13.5%) was higher among those with moderate-to-severe obesity, in patients with acanthosis nigricans and was associated with other cardiovascular disease risk factors. CONCLUSIONS: We found no children with T2DM. The prevalence of IGT and IR was related to severity of obesity, to the association of acanthosis nigricans and was associated with cardiovascular risk.

Genetic reanalysis of patients with a difference of sex development carrying the NR5A1/SF-1 variant p.Gly146Ala has discovered other likely disease-causing variations.

NR5A1/SF-1 (Steroidogenic factor-1) variants may cause mild to severe differences of sex development (DSD) or may be found in healthy carriers. The NR5A1/SF-1 c.437G>C/p.Gly146Ala variant is common in individuals with a DSD and has been suggested to act as a susceptibility factor for adrenal disease or cryptorchidism. Since the allele frequency is high in the general population, and the functional testing of the p.Gly146Ala variant revealed inconclusive results, the disease-causing effect of this variant has been questioned. However, a role as a disease modifier is still possible given that oligogenic inheritance has been described in patients with NR5A1/SF-1 variants. Therefore, we performed next generation sequencing (NGS) in 13 DSD individuals harboring the NR5A1/SF-1 p.Gly146Ala variant to search for other DSD-causing variants and clarify the function of this variant for the phenotype of the carriers. Panel and whole-exome sequencing was performed, and data were analyzed with a filtering algorithm for detecting variants in NR5A1- and DSD-related genes. The phenotype of the studied individuals ranged from scrotal hypospadias and ambiguous genitalia in 46,XY DSD to opposite sex in both 46,XY and 46,XX. In nine subjects we identified either a clearly pathogenic DSD gene variant (e.g. in AR) or one to four potentially deleterious variants that likely explain the observed phenotype alone (e.g. in FGFR3, CHD7). Our study shows that most individuals carrying the NR5A1/SF-1 p.Gly146Ala variant, harbor at least one other deleterious gene variant which can explain the DSD phenotype. This finding confirms that the NR5A1/SF-1 p.Gly146Ala variant may not contribute to the pathogenesis of DSD and qualifies as a benign polymorphism. Thus, individuals, in whom the NR5A1/SF-1 p.Gly146Ala gene variant has been identified as the underlying genetic cause for their DSD in the past, should be re-evaluated with a NGS method to reveal the real genetic diagnosis.

Familial hyperinsulinism-hyperammonemia syndrome in a family with seizures: case report.

Hyperinsulinism-hyperammonemia (HI/HA) syndrome is the second most frequent cause of congenital hyperinsulinism (CHI) and it is characterized by recurrent symptomatic hypoglycemia and persistent hyperammonemia. We describe the familial case of a 2-year-old child and her 32-year-old mother who, having suffered from tonic-clonic seizures since infancy, had both been diagnosed with epilepsy and treated with sodium valproate. Hypoglycemia was identified in the child in routine analysis. Six days after admission, a complete study of hypoglycemia showed test results compatible with hyperinsulinemic hypoglycemia and hyperammonemia. A mutation in the GDH gene (Arg269His) confirmed the diagnosis in both the mother and the child. An important peculiarity of this case is the diagnosis of a 32-year-old woman, previously diagnosed with epilepsy through her daughter's diagnosis at a Pediatric Endocrinology Department and subsequently treated ineffectively with sodium valproate. We conclude that, as hypoglycemia may be subtle, the diagnosis of HI/HA should be considered in children or adults with seizures/epilepsy and hyperammonemia, serum ammonia being a simple screening test for the disease.

Forty-One Individuals With Mutations in the AVP-NPII Gene Associated With Familial Neurohypophyseal Diabetes Insipidus.

CONTEXT: Familial neurohypophyseal diabetes insipidus is a rare disease produced by a deficiency in the secretion of antidiuretic hormone and is caused by mutations in the arginine vasopressin gene. OBJECTIVE: Clinical, biochemical, and genetic characterization of a group of patients clinically diagnosed with familial neurohypophyseal diabetes insipidus, 1 of the largest cohorts of patients with protein neurophysin II (AVP-NPII) gene alterations studied so far. DESIGN: The AVP-NPII gene was screened for mutations by PCR followed by direct Sanger sequencing in 15 different unrelated families from Spain. RESULTS: The 15 probands presented with polyuria and polydipsia as the most important symptoms at the time of diagnosis. In these patients, the disease was diagnosed at a median of 6 years of age. We observed 11 likely pathogenic variants. Importantly, 4 of the AVP-NPII variants were novel (p.(Tyr21Cys), p.(Gly45Ser), p.(Cys75Tyr), p.(Gly88Cys)). CONCLUSIONS: Cytotoxicity seems to be due to consequences common to all the variants found in our cohort, which are not able to fold correctly and pass the quality control of the ER. In concordance, we found autosomal dominant familial neurohypophyseal diabetes insipidus in the 15 families studied.

Normal intellectual development in children born from women with hypothyroxinemia during their pregnancy.

Proper maternal thyroid function is known to be essential for neural differentiation and migration in the fetus during the first half of pregnancy. The objectives of this study were to assess the relationship between thyroxin levels, in pregnant women with no thyroid disease and the intellectual development of their offspring in a non-iodine-deficient area, and to know specifically whether or not isolated hypothyroxinemia during pregnancy was associated with a lower intelligence in the offspring. Previously we had publicated values TSH, FT4, free T3 (FT3), anti-thyroid peroxidase antibodies (TPO Abs) and urinary iodine concentration (UIC) in 1322 pregnant women in our hospital area. Now we presented results of intelligence quotient in children born from these pregnancies. We assessed 455 children at one year of age using Brunet-Lezine scale. Of these, 289 children were evaluated again at 6-8 years of age using the WISC-IV. From the total group of children recruited, we established as control subgroup, children born of rigorously normal pregnancies (women with UIC > 150 µg/L, FT4>10th percentile and TPO-Ab negative in both trimesters). The remaining children were divided into two subgroups: those born to mothers with FT4 below the 10th percentile and the rest. No correlation was found between FT4 maternal levels, in either of trimesters studied, and the intellectual scores of offspring. No differences were found in intellectual scores comparing children born to mothers with hypothyroxinemia and those whose mothers were euthyroxinemic in both trimesters, or with the control subgroup. As conclusions we did not find any association between the levels of maternal FT4 during pregnancy and the subsequent intellectual development the offspring from these pregnancies. We attribute this result to the fact that all the pregnant women included had normal thyroid function.

[Obesity associated metabolic impairment is evident at early ages: Spanish collaborative study]. / Las alteraciones metabólicas asociadas a la obesidad están ya presentes en los primeros años de vida: estudio colaborativo español.

UNLABELLED: The objectives of this study are to provide a description of the demographic, anthropometric characteristics and metabolic abnormalities in children with early-onset (< 10 years) and of very-early-onset obesity (< 5 years). We also evaluate the diagnostic ability using the definition of metabolic syndrome (MS) according to different criteria. METHODS: It is a retrospective, case-control, cross-sectional, multicenter study. A total of 10 Pediatric Endocrinology Units in different Spanish hospitals were involved. A group of 469 children with early-onset obesity and another group of 30 children with very early-onset obesity were studied. The control group consisted of 224 healthy children younger than 10 years. Anthropometric and analytical determination of carbohydrates metabolism parameters and the lipid profile were performed. RESULTS: The presence of metabolic alterations associated with obesity in children and adolescents in Spain is remarkable, either on their own, or encompassed within the definition of MS. This prevalence increases substantially when considering the peripheral resistance to insulin action as a diagnostic criterion. It also shows how children who could not be diagnosed with MS according to the definition provided by the International Diabetes Federation (IDF) due to age below 10 years, these alterations are already present in a remarkable percentage. In fact, metabolic abnormalities are already present in the very-early-onset obese children ( <5 years). CONCLUSION: In Spanish children there are metabolic alterations associated with obesity in the infant-juvenile stages alone or encompassed within the definition of MS,and are already present at earlier ages.

Los objetivos de este estudio son, realizar una descripción de las características demográficas, antropométricas y de las alteraciones metabólicas de niños atendidos por obesidad resaltando las características aquellos casos de obesidad de inicio temprano (< 10 años) y los de inicio precoz (< 5 años), y evaluar la capacidad diagnóstica de la definición de síndrome metabólico (SM) según diferentes criterios. Métodos: Es un estudio retrospectivo, caso-control, transversal, multicéntrico. Han participado un total de 10 Unidades de Endocrinología Pediátrica de diferentes hospitales españoles con un grupo de 469 niños con obesidad de inicio temprano y otro grupo de 30 niños con obesidad de inicio precoz. El grupo control estuvo constituido por 224 niños sanos menores de 10 años. Se realizó una valoración antropométrica y determinación analítica de parámetros del metabolismo de los hidratos de carbono y lipidograma. Resultados: La presencia de alteraciones metabólicas asociadas a la obesidad en la etapa infanto-juvenil en España es notable, de forma aislada, o englobada bajo la definición de SM. La prevalencia de éste aumenta sustancialmente cuando se considera la resistencia periférica a la acción de la insulina como criterio diagnóstico. Se demuestra cómo en niños menores de 10 años, dichas alteraciones están presentes en un porcentaje reseñable, y se encuentran las primeras alteraciones metabólicas ya en niños obesos < 5 años. Conclusión: En los niños españoles existen alteraciones metabólicas asociadas a la obesidad en la etapa infanto- juvenil de forma aislada o englobada bajo la definición de SM, y ya están presentes a edades precoces.

Urinary iodine and thyroid function in a population of healthy pregnant women in the North of Spain.

BACKGROUND: Iodine is an essential trace element for the synthesis of thyroid hormones, which are keys in maternal metabolism during pregnancy as well as in neurological development during fetal and postnatal life. This was a prospective study on iodine status and thyroid function in women during pregnancy in the Basque country to assess whether there was any relationship among maternal urinary iodine, maternal thyroid function and thyrotropin (TSH) in newborns, and to explore any difference in women experiencing miscarriages. METHODS: We analyzed TSH, free T(4) (FT(4)), free T(3) (FT(3)), thyroid peroxidase antibody (TPO-Ab) titers in serum and urinary iodine concentrations (UIC) in 2104 women in the first trimester of pregnancy and in 1322 of them in their second trimester. We obtained neonatal TSH levels in 1868 cases. RESULTS: In the first (T1) and second trimesters (T2), the median UICs were 88.5 µg/L and 140 µg/L, respectively. No relationship was found between UIC and FT4, or maternal and neonatal TSH. In T1 and T2, 9.7% and 7.5% of women were TPO-Ab positive, respectively. The total miscarriage rate was 10%. The percentage of miscarriages in healthy women was 8.9%, lower than in women with overt hypothyroidism (21.2%; p < 0.001) and than in women with subclinical hypothyroidism (15.6%; p < 0.025). The miscarriage rate was not higher in TPO-Ab-positive women. CONCLUSIONS: In this study most women had iodine deficiency during pregnancy. Neonatal TSH is not correlated with maternal UIC during pregnancy. Pregnant women with hypothyroidism have a higher rate of miscarriages.