Clinical, genetic and functional characteristics of three novel CYP17A1 mutations causing combined 17alpha-hydroxylase/17,20-lyase deficiency.

BACKGROUND: P450c17 has two distinct activities: 17alpha-hydroxylase activity and 17,20-lyase activity. Combined 17alpha-hydroxylase/17,20-lyase deficiency leads to a severe defect in the production of cortisol and sex steroids. In affected males this results in impaired masculinization with ambiguous or female external genitalia. Female patients have normal genitalia but show a lack of pubertal development in adolescence. An increased production of mineralocorticoids often leads to hypertension and hypokalemia in both sexes. METHODS: To better understand the mechanisms of P450c17 deficiency, we studied 2 patients (both 46,XY) with combined 17alpha-hydroxylase/17,20-lyase deficiency of different severity: one with complete lack of masculinization and one with ambiguous genitalia. RESULTS: Four mutations were identified by sequencing of the CYP17A1 gene: I332T and A355T in the less severely affected patient; G111S and R440H in the patient with complete lack of masculinization. The three novel mutations were expressed in COS1 cells and all mutant proteins except I332T showed a complete loss of both enzymatic activities. I332T retained some residual 17alpha-hydroxylase as well as 17,20-lyase activity. CONCLUSION: We identified 2 patients with the phenotypical spectrum of P450c17 deficiency. Three novel mutations in the CYP17A1 gene were identified and their functional characterization provided a good phenotype-genotype correlation. The location of the mutated residues in the three-dimensional model of P450c17 gave some additional insights into its structure-function relationship.

Target setting in intensive insulin management is associated with metabolic control: the Hvidoere childhood diabetes study group centre differences study 2005.

OBJECTIVE: To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control. METHODS: Clinical data and questionnaires were completed by adolescents, parents/carers and diabetes teams in 21 international centres. HbA1c was measured centrally. RESULTS: A total of 2062 adolescents completed questionnaires (age 14.4 +/- 2.3 yr; diabetes duration 6.1 +/- 3.5 yr). Mean HbA 1c = 8.2 +/- 1.4% with significant differences between centres (F = 12.3; p < 0.001) range from 7.4 to 9.1%. There was a significant correlation between parent (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p < 0.001), and a stronger association between parents' (r = 0.39) and adolescents' (r = 0.4) reports of the HbA1c they would be happy with and their actual HbA1c result. There were significant differences between centres on parent and adolescent reports of ideal and happy with HbA1c (8.1 < F > 17.4;p < 0.001). A lower target HbA1c and greater consistency between members of teams within centres were associated with lower centre HbA1c (F = 16.0; df = 15; p < 0.001). CONCLUSIONS: Clear and consistent setting of glycaemic targets by diabetes teams is strongly associated with HbA1c outcome in adolescents. Target setting appears to play a significant role in explaining the differences in metabolic outcomes between centres.

Basal lipolysis, not the degree of insulin resistance, differentiates large from small isolated adipocytes in high-fat fed mice.

AIMS/HYPOTHESIS: Adipocytes in obesity are characterised by increased cell size and insulin resistance compared with adipocytes isolated from lean patients. However, it is not clear at present whether hypertrophy actually does drive adipocyte insulin resistance. Thus, the aim of the present study was to metabolically characterise small and large adipocytes isolated from epididymal fat pads of mice fed a high-fat diet (HFD). METHODS: C57BL/6J mice were fed normal chow or HFD for 8 weeks. Adipocytes from epididymal fat pads were isolated by collagenase digestion and, in HFD-fed mice, separated into two fractions according to their size by filtration through a nylon mesh. Viability was assessed by lactate dehydrogenase and 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium assays. Basal and insulin-stimulated D-[U-(14)C]glucose incorporation and lipolysis were measured. Protein levels and mRNA expression were determined by western blot and real-time RT-PCR, respectively. RESULTS: Insulin-stimulated D-[U-(14)C]glucose incorporation into adipocytes isolated from HFD-fed mice was reduced by 50% compared with adipocytes from chow-fed mice. However, it was similar between small (average diameter 60.9 +/- 3.1 microm) and large (average diameter 83.0 +/- 6.6 microm) adipocytes. Similarly, insulin-stimulated phosphorylation of protein kinase B and AS160 were reduced to the same extent in small and large adipocytes isolated from HFD-mice. In addition, insulin failed to inhibit lipolysis in both adipocyte fractions, whereas it decreased lipolysis by 30% in adipocytes of chow-fed mice. In contrast, large and small adipocytes differed in basal lipolysis rate, which was twofold higher in the larger cells. The latter finding was associated with higher mRNA expression levels of Atgl (also known as Pnpla2) and Hsl (also known as Lipe) in larger adipocytes. Viability was not different between small and large adipocytes. CONCLUSIONS/INTERPRETATION: Rate of basal lipolysis but not insulin responsiveness is different between small and large adipocytes isolated from epididymal fat pads of HFD-fed mice.

Are family factors universally related to metabolic outcomes in adolescents with Type 1 diabetes?

AIMS: To assess the importance of family factors in determining metabolic outcomes in adolescents with Type 1 diabetes in 19 countries. METHODS: Adolescents with Type 1 diabetes aged 11-18 years, from 21 paediatric diabetes care centres, in 19 countries, and their parents were invited to participate. Questionnaires were administered recording demographic data, details of insulin regimens, severe hypoglycaemic events and number of episodes of diabetic ketoacidosis. Adolescents completed the parental involvement scale from the Diabetes Quality of Life for Youth--Short Form (DQOLY-SF) and the Diabetes Family Responsibility Questionnaire (DFRQ). Parents completed the DFRQ and a Parental Burden of Diabetes score. Glycated haemoglobin (HbA(1c)) was analysed centrally on capillary blood. RESULTS: A total of 2062 adolescents completed a questionnaire, with 2036 providing a blood sample; 1994 parents also completed a questionnaire. Family demographic factors that were associated with metabolic outcomes included: parents living together (t = 4.1; P < 0.001), paternal employment status (F = 7.2; d.f. = 3; P < 0.001), parents perceived to be over-involved in diabetes care (r = 0.11; P < 0.001) and adolescent-parent disagreement on responsibility for diabetes care practices (F = 8.46; d.f. = 2; P < 0.001). Although these factors differed between centres, they did not account for centre differences in metabolic outcomes, but were stronger predictors of metabolic control than age, gender or insulin treatment regimen. CONCLUSIONS: Family factors, particularly dynamic and communication factors such as parental over-involvement and adolescent-parent concordance on responsibility for diabetes care appear be important determinants of metabolic outcomes in adolescents with diabetes. However, family dynamic factors do not account for the substantial differences in metabolic outcomes between centres.

Improved glucose tolerance in mice receiving intraperitoneal transplantation of normal fat tissue.

AIMS/HYPOTHESIS: The association between increased (visceral) fat mass, insulin resistance and type 2 diabetes mellitus is well known. Yet, it is unclear whether the mere increase in intra-abdominal fat mass, or rather functional alterations in fat tissue in obesity contribute to the development of insulin resistance in obese patients. Here we attempted to isolate the metabolic effect of increased fat mass by fat tissue transplantation. METHODS: Epididymal fat pads were removed from male C57Bl6/J mice and transplanted intraperitoneally into male littermates (recipients), increasing the combined perigonadal fat mass by 50% (p < 0.005). At 4 and 8 weeks post-transplantation, glucose and insulin tolerance tests were performed, and insulin, NEFA and adipokines measured. RESULTS: Circulating levels of NEFA, adiponectin and leptin were not significantly different between transplanted and sham-operated control mice, while results of the postprandial insulin tolerance test were similar between the two groups. In contrast, under fasting conditions, the mere increase in intra-abdominal fat mass resulted in decreased plasma glucose levels (6.9 +/- 0.4 vs 8.1 +/- 0.3 mmol/l, p = 0.03) and a approximately 20% lower AUC in the glucose tolerance test (p = 0.02) in transplanted mice. Homeostasis model assessment of insulin resistance (HOMA-IR) was 4.1 +/- 0.4 in transplanted mice (vs 6.2 +/- 0.7 in sham-operated controls) (p = 0.02), suggesting improved insulin sensitivity. Linear regression modelling revealed that while total body weight positively correlated, as expected, with HOMA-IR (beta: 0.728, p = 0.006), higher transplanted fat mass correlated with lower HOMA-IR (beta: -0.505, p = 0.031). CONCLUSIONS/INTERPRETATION: Increasing intra-abdominal fat mass by transplantation of fat from normal mice improved, rather than impaired, fasting glucose tolerance and insulin sensitivity, achieving an effect opposite to the expected metabolic consequence of increased visceral fat in obesity.

WNT4 deficiency--a clinical phenotype distinct from the classic Mayer-Rokitansky-Kuster-Hauser syndrome: a case report.

The pathways leading to female sexual determination in mammals are incompletely defined. Loss-of-function mutations in the WNT4 gene appear to cause developmental abnormalities of sexual differentiation in women and mice. We recruited six patients with different degrees of Müllerian abnormalities, with or without renal aberrations and a normal female 46,XX karyotype. A clear androgen excess was found only in one patient. This 19-year-old woman was affected by primary amenorrhoea, absence of Müllerian ducts derivatives, clinical (acne and hirsutism) and biochemical (repeatedly high levels of testosterone) signs of androgen excess. Direct sequencing of her WNT4 gene followed by functional studies in human ovarian cells (OVCAR3) was performed. This patient carried the novel R83C loss-of-function dominant negative mutation in her WNT4, confirming the role of WNT4 in the development and maintenance of the female phenotype in women. Our study can also help refine the phenotype of WNT4 deficiency in humans. In fact, it appears that at least in this limited casuistic small group of patients, the absence of a uterus (and not other Müllerian abnormalities) and the androgen excess are the pathognomonic signs of WNT4 defects, suggesting that this might be a clinical entity distinct from the classic Mayer-Rokitansky-Kuster-Hauser syndrome.

P450c17 deficiency: clinical and molecular characterization of six patients.

CONTEXT: The characteristics of P450c17 deficiency include 46,XY disorder of sex development, hypertension, hypokalemia, and lack of pubertal development. OBJECTIVE: To better understand this rare enzymatic deficiency, we analyzed the CYP17A1 gene in six affected patients. DESIGN AND PATIENTS: We examined six patients, five 46,XY, and one 46,XX (age 9-29 yr) with complete lack of masculinization (female infantile external genitalia, no uterus) and delayed puberty, respectively, and different degrees of hypertension. MAIN OUTCOME MEASUREMENTS: Genotype-phenotype correlation was measured. RESULTS: Four homozygote mutations were identified by direct sequencing of the CYP17A1 gene corresponding to an alanin 302-proline (A302P) exchange; the loss of lysine 327 (K327del); the deletion of glutamate 331 (E331del); and the replacement of arginine 416 with a histidine (R416H). Both P450c17 activities were abolished in all the mutant proteins, except one, when expressed in COS1 cells. The E331del-mutated P450c17 retained 17alpha-hydroxylase activity. The mutant proteins were normally expressed, suggesting that the loss of enzymatic activity is not due to defects of synthesis, stability, or localization of P450c17 proteins. CONCLUSION: These studies confirm lack of masculinization in 46,XY individuals as the pathognomic sign of the complete P450c17 deficiency. In XX individuals P450c17 deficiency should be considered in cases of delayed puberty. Age of onset and the severity of hypertension do not seem to be constant. Careful examination of long-term follow-ups in two of our patients suggested to us that estrogen treatment in P450c17-deficient patients might worsen the enzymatic defect, leading to aggravation of the hypertension.

Association of childhood type 1 diabetes mellitus with a variant of PAX4: possible link to beta cell regenerative capacity.

AIMS/HYPOTHESIS: Loss of pancreatic beta cells is the crucial event in the development of type 1 diabetes. It is the result of an imbalance between autoimmune destruction and insufficient regeneration of islet cells. To study the role of islet cell regeneration in the pathogenesis of type 1 diabetes, we focused on PAX4, a paired homeodomain transcriptional repressor that is involved in islet cell growth. METHODS: The study included 379 diabetic children and 1,070 controls from two distinct populations, and a cohort of children who had not developed type 1 diabetes, despite the presence of islet cell antibodies. Genomic DNA analysis of PAX4 was carried out via direct sequencing of PCR-amplified fragments and allelic discrimination. We compared the transrepression potential of the PAX4 variants in betaTC3 cells and analysed their influence on beta cell growth. RESULTS: The type 1 diabetic subjects are different from the normal individuals in terms of the genotype distribution of the A1168C single nucleotide polymorphism in PAX4. The C/C genotype is frequent among type 1 diabetic children (73%) and rare among the control population (32%). Conversely, the A/C genotype is prevalent among control subjects (62%) and antibody-positive children without type 1 diabetes (73.6%), but uncommon among subjects with type 1 diabetes (17.5%). The combination of PAX4A and PAX4C is functionally more active than PAX4C alone (the "diabetic" variant). Beta cells expressing PAX4A and PAX4C efficiently proliferate when stimulated with glucose, whereas cells expressing the PAX4C variant alone do not. CONCLUSIONS/INTERPRETATION: We have identified a link between beta cell regenerative capacity and susceptibility to type 1 diabetes. This finding could explain the fact that not all of the individuals who develop autoimmunity against beta cells actually contract the disease. The C/C genotype of the A1168C polymorphism in PAX4 can be viewed as a predisposition marker that can help to detect individuals prone to develop type 1 diabetes.

Impaired intellectual development in children with Type I diabetes: association with HbA(1c), age at diagnosis and sex.

AIMS/HYPOTHESIS: Good metabolic control in diabetic children is already crucial before puberty to prevent diabetic complications later in life. However, tight metabolic control could increase the risk of severe hypoglycaemia, which might be responsible for impaired intellectual performance later in life. The purpose of this prospective longitudinal study was to evaluate the relevance of long-term metabolic control and hypoglycaemia possibly affecting the intellectual development of young children with Type I (insulin-dependent) diabetes mellitus. METHODS: The intellectual development in 64 diabetic children between the ages of 7 and 16 years was assessed at least four times using the German version of the Hamburg Wechsler intelligence scale for preschool children, Children-Revised and by the "Adaptives Intelligenz Diagnostikum" (Adaptive Intelligence Diagnosticum). Data were analysed longitudinally compared with a control group. RESULTS: A significant decline in performance by age 7 and in verbal intelligence quotient between age 7 and 16 years was observed in diabetic boys diagnosed before the age of 6 but not in those diagnosed later and not in diabetic girls. The deterioration of intellectual performance in boys diagnosed at a very young age was not associated with the occurrence of severe hypoglycaemic episodes but was correlated with the degree of metabolic deterioration at diagnosis and with high long-term average of glycated haemoglobin. CONCLUSION/INTERPRETATION: Our study in diabetic children shows that the male sex, diagnosis at a young age, metabolic condition at diagnosis and long-term metabolic control, rather than experienced hypoglycaemic attacks are risk factors for intellectual development.

Incidence of enteropathy-associated T-cell lymphoma in celiac disease: implications for children and adolescents with type 1 diabetes.

The long-term consequences of screening for celiac disease in diabetic children are not known. Routine screening is not practiced in our pediatric diabetic population. This study of the incidence of the most severe and specific long-term complication of untreated celiac disease, i.e., enteropathy-associated T-cell lymphoma (EATCL) and its association with diabetes, is done in order to justify our strategy not to practice routine screening. In the first phase of this study, a questionnaire was sent to all Swiss pathologists. The second phase consisted of a search in the cancer registry of the canton of Zurich. The incidence of EATCL in the general population of a Swiss region and the theoretical risk for a diabetic patient to develop this type of lymphoma were calculated. Ten cases of EATCL were found. Five had a long history of malabsorption, three of them since childhood. The mean age of the patients was 61.9 yr. None suffered from diabetes mellitus. The incidence of EATCL was 0.07/100,000 inhabitants/year. The expected risk for EATCL in patients with type 1 diabetes is 12.4/100,000 diabetic patients over a period of 60 yr. The data suggest that the risk for EATCL is small in diabetic patients. Therefore, we restrict the investigation for celiac disease to patients with typical and atypical symptoms, but do not perform routine screening.

Persistent differences among centers over 3 years in glycemic control and hypoglycemia in a study of 3,805 children and adolescents with type 1 diabetes from the Hvidøre Study Group.

OBJECTIVE: Twenty-one international pediatric diabetes centers from 17 countries investigated the effect of simple feedback about the grand mean HbA(1c) level of all centers and the average value of each center on changes in metabolic control, rate of severe hypoglycemia, and insulin therapy over a 3-year period. RESEARCH DESIGN AND METHODS: Clinical data collection and determination of HbA(1c) levels were conducted at a central location in 1995 (n = 2,780, age 0-18 years) and 1998 (n = 2,101, age 11-18 years). RESULTS: Striking differences in average HbA(1c) concentrations were found among centers; these differences remained after adjustment for the significant confounders of sex, age, and diabetes duration. They were apparent even in patients with short diabetes duration and remained stable 3 years later (mean adjusted HbA(1c) level: 8.62 +/- 0.03 vs. 8.67 +/- 0.04 [1995 vs. 1998, respectively]). Three centers had improved significantly, four centers had deteriorated significantly in their overall adjusted HbA(1c) levels, and 14 centers had not changed in glycemic control. During the observation period, there were increases in the adjusted insulin dose by 0.076 U/kg, the adjusted number of injections by 0.23 injections per day, and the adjusted BMI by 0.95 kg/m(2). The 1995 versus 1998 difference in glycemic control for the seven centers could not be explained by prevailing insulin regimens or rates of hypoglycemia. CONCLUSIONS: This study reveals significant outcome differences among large international pediatric diabetes centers. Feedback and comparison of HbA(1c) levels led to an intensification of insulin therapy in most centers, but improved glycemic control in only a few.

[Growth disorders in the child]. / Wachstumsstörungen beim Kind.

The ability to interpret growth of a child is dependent on the availability of earlier data of the child and of data concerning the family. Most important is the recording of growth data on a growth chart by the family doctor or the paediatrician. In addition, parental height allows the calculation of the patients target height. The exact interpretation of bone age using a x-ray of the hand is imperative. The most common "disturbances of growth" are variants of the norm, like familial short stature or retardation of growth and development, or--not rarely--a combination of both. A simple flow sheet is helpful in determining if further endocrine investigation are needed.

Epidemiology of type I diabetes mellitus in Switzerland: steep rise in incidence in under 5 year old children in the past decade.

AIMS/HYPOTHESIS: In this nationwide prospective study we wanted to verify the trend of increasing diabetes incidence data from our earlier retrospective analysis of the military registry of Swiss men. SUBJECTS AND METHODS: The data collection of newly diagnosed children in Switzerland at an age younger than 15 years started in 1991. The countrywide survey used a small questionnaire which was sent back to the study centre. The questionnaire was anonymous and contained: hospital of diagnosis, initials, sex, birth date, date of diagnosis, residence, country of citizenship, and responsible physician. General data on the population were taken from publications of the Swiss Federal Statistical Office. RESULTS: A total of 941 children below the age of 15 years with newly diagnosed Type I (insulin-dependent) diabetes mellitus were collected (434 girls, 507 boys). The incidence in children aged 0 to 14 years rose significantly between 1991 and 1999 with a yearly average increase of 5.1%. In the age group 0 to 4 years a more than four-fold increase in incidence from 2.4/100,000 per year to 10.5/100,000 per year (p = 0.0002) was recorded, whereas the age-specific incidence in the 5 to 9-year-old and 10 to 14-year-old children did not change during the data collection period. The incidence was significantly higher in boys than in girls, whereas no difference was found between rural and urban populations. CONCLUSION/INTERPRETATION: The incidence of Type I diabetes is rising in children living in Switzerland but only the youngest age group of under 5 years of age is affected showing a large annual average increase of 23.8%.

A novel mutation in the anti-müllerian hormone gene as cause of persistent müllerian duct syndrome.

UNLABELLED: Persistent müllerian duct syndrome is a relatively rare inherited defect of sexual differentiation characterised by failure of regression of the müllerian ducts in males. In affected individuals, uterus and tubes are present because of defects of synthesis or action of anti-müllerian hormone (AMH), normally produced by the Sertoli cells of the testis. Patients are normally virilised, although mono- or bilateral cryptorchidism may be present. We observed two brothers (chromosomes 46 XY), aged 11 years and 2 months and 8 years and 3 months respectively, with bilateral cryptorchidism. The diagnosis of persistent müllerian duct syndrome was made on the basis of laparoscopic evidence of uterus and tubes, undetectable plasma levels of AMH and a 23 base pair duplicative insertion in exon 5 of the AMH gene, causing the introduction of a premature stop codon, homozygous in the two brothers. The surgical correction of the genital abnormalities was successfully carried out by laparoscopic orchidopexy according to Fowler-Stephens. CONCLUSION: Persistent müllerian duct syndrome should be taken into consideration in all cases of bilateral cryptorchidism. Laparoscopy is the elective procedure for diagnosis of this disease and laparoscopic surgery for orchidopexy of intra-abdominal testes. Mutation analysis of the anti-müllerian hormone gene in these patients helps to understand the structure-function relationship of the anti-müllerian hormone protein, although it is not clear at present whether anti-müllerian hormone is necessary to maintain normal testicular function.

Apparently normal ovarian differentiation in a prepubertal girl with transcriptionally inactive steroidogenic factor 1 (NR5A1/SF-1) and adrenocortical insufficiency.

Steroidogenic factor 1 (NR5A1/SF-1) plays an essential role in the development of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes, controlling expression of their many important genes. The recent description of a 46,XY patient bearing a mutation in the NR5A1 gene, causing male pseudohermaphroditism and adrenal failure, demonstrated the crucial role of SF-1 in male gonadal differentiation. The role of SF-1 in human ovarian development was, until now, unknown. We describe a phenotypically and genotypically normal girl, with signs and symptoms of adrenal insufficiency and no apparent defect in ovarian maturation, bearing a heterozygote G-->T transversion in exon 4 of the NR5A1 gene that leads to the missense R255L in the SF-1 protein. The exchange does not interfere with protein translation and stability. Consistent with the clinical picture, R255L is transcriptionally inactive and has no dominant-negative activity. The inability of the mutant (MUT) NR5A1/SF-1 to bind canonical DNA sequences might offer a possible explanation for the failure of the mutant protein to transactivate target genes. This is the first report of a mutation in the NR5A1 gene in a genotypically female patient, and it suggests that NR5A1/SF-1 is not necessary for female gonadal development, confirming the crucial role of NR5A1/SF-1 in adrenal gland formation in both sexes.

Genomic structure, chromosomal localization, and expression pattern of the human LIM-homeobox3 (LHX 3) gene.

Lhx3 is a LIM-homeobox protein essential for pituitary development in mice. The human homologue gene spans 7.2 kb and contains 7 exons, including two alternatively spliced first exons. This structure encodes two distinct protein isoforms, LHX3a and LHX3b, that differ exclusively in their amino-terminus. The LHX3 gene was localized at 9q34.2-34.3. The predicted protein sequence is highly homologous to other known Lhx3 proteins, the highest degree of homology being in the conserved domains. The highest expression of LHX3 was found in pituitary gland, spinal cord, and lung. Among different pituitary cell types, corticotrophs appear to express preferentially LHX3b isoform, suggesting a distinct role of the b-form in the development of this cell lineage. Although the human LHX3 gene structure would provide a ground for clarification of the molecular basis of complete anterior pituitary deficiency, we were unable to identify any mutation in the LHX3 gene of 46 such patients.

Effect of leptin on CYP17 enzymatic activities in human adrenal cells: new insight in the onset of adrenarche.

CYP17 is a microsomal enzyme embodying two distinct activities, 17alpha-hydroxylase and 17,20-lyase, essential for the synthesis of cortisol and sex hormone precursors, respectively. The two activities are differentially regulated in a tissue and developmental stage-dependent fashion. Leptin might play a role in such differential control. Low dose leptin caused a significant increase in 17,20-lyase activity in adrenal NCI-H295R cells expressing leptin (OB) receptor (OB-R), without significant sustained influence on the 17alpha-hydroxylase activity. To analyze the time dependence of this leptin effect, the impact of long and short-term leptin treatment was studied. To assess the relationship with the OB-R signal transduction pathway, the same experiments were performed in intact cells and in a reconstituted system. The long- and short-term studies in intact cells and in microsomes suggest that the 17alpha-hydroxylase activity of CYP17 can be promptly stimulated by leptin, but that the effect is transient. In contrast, physiological doses of leptin steadily enhance 17,20-lyase activity. This influence is direct, OB-R specific and dependent on the integrity of the signal transduction pathway. The 17,20-lyase activity stimulation relies on phosphate incorporation, as demonstrated by the loss of leptin-dependent 17,20-lyase stimulation after phosphate removal, and by the fact that the DHEA production appears to be related exclusively to the presence of phosphorylated CYP17, independently from novel protein synthesis. The mechanism underlying the observed events seems to involve CYP17 phosphorylation, a feature of the OBR signal transduction pathway, and a process already shown to be crucial for 17,20-lyase activity.

Central diabetes insipidus as the first manifestation of neurosarcoidosis in a 10-year-old girl.

Central diabetes insipidus with thickening of the pituitary stalk has been demonstrated in adults with Langerhans cell histiocytosis (LCH), tuberculosis or sarcoidosis, and in children with LCH. We present a 10.5-year-old girl with central diabetes insipidus. Magnetic resonance imaging (MRI) revealed thickening of the central part of the pituitary stalk and multiple hyperintense lesions in the frontal white matter on T(2)-weighted images. Laboratory findings were normal except for an elevated serum angiotensin-converting enzyme (ACE) level. The MRI findings together with the elevated serum ACE level highly suggest the diagnosis of sarcoidosis. We conclude that central diabetes insipidus can be the first clinical manifestation of sarcoidosis in children.

Ten-year follow-up in a boy with Leydig cell tumor after selective surgery.

In a 4(8)/12-year-old boy with precocious puberty and an enlarged right testis, a Leydig cell tumor was diagnosed. Surgical exploration revealed an encapsulated tumor which was selectively removed without orchiectomy. Within 1 year the signs of precocious puberty disappeared. Ten years later, the patient remained free of disease and had developed normal spontaneous puberty. Despite of highly advanced bone age at the time of diagnosis (13 years according to Greulich and Pyle), his height at age 15 was in the upper normal range and within the familial target height. Most of these prepubertal patients affected by this tumor underwent orchiectomy, although no malignant course of Leydig cell tumors before puberty has been reported. This work provides the first example of long-term follow-up of a prepubertal boy after testis-sparing surgery for a Leydic cell tumor. We conclude that selective removal of the tumor may be the procedure of choice in this entity.