Genetic evidence of the programming of beta cell mass and function by glucocorticoids in mice.

AIMS/HYPOTHESIS: Prenatal exposure to excess glucocorticoids associates with low birthweight in rodents, primates and humans and its involvement in programming glucose homeostasis is suspected. Our aim was to further dissect the role of glucocorticoids on beta cell development and function in mice. METHODS: Using the model of maternal general food restriction during the last week of pregnancy, we thoroughly studied in the CD1 mouse-mothers and fetal and adult offspring--the pancreatic, metabolic and molecular consequences of maternal undernutrition associated with excess glucocorticoids. The specific involvement of the glucocorticoid receptor (GR) was studied in mutant fetuses lacking GR in pancreatic precursors or mature beta cells. RESULTS: Maternal general food restriction in the mouse is associated with decreased maternal glucose and increased corticosterone levels. Fetuses from underfed dams had increased corticosterone levels, decreased pancreatic endocrine gene expression but increased exocrine gene expression and a lower beta cell mass. The offspring of these dams had a low birthweight, permanent postnatal growth retardation and, as adults, impaired glucose tolerance, decreased beta cell mass (-50%) and massively reduced islet expression (-80%) of most of the genes involved in beta cell function (e.g. Pdx1, Sur1 [also known as Abcc8], insulin). Moreover, using mutant fetuses lacking GR in pancreatic precursors or beta cells we show that the deleterious effect of undernutrition on fetal beta cell development requires the presence of the GR in pancreatic precursor cells. CONCLUSIONS/INTERPRETATION: These results demonstrate the crucial role of excess fetal glucocorticoids and the importance of GR signalling in progenitor cells to programme beta cell mass and dysfunction.

Otologic disorders in Turner syndrome.

INTRODUCTION: Patients with Turner syndrome (TS) have craniofacial malformations, such as Eustachian tube hypoplasia and dysfunction and velar dysfunction, which foster acute otitis media. The aim of this study was to inventory pediatric otologic disorders in patients with TS at their first ENT consultation in our center. PATIENTS AND METHODS: We reviewed the ENT consultation data of pediatric TS patients followed in our center between 2005 and 2015: otoscopy, hearing threshold, and history of acute otitis media or ENT surgery. Data were compared according to karyotype: X monosomy (45,X), mosaic (45,X/46,XX), isochromosome (46,Xi [Xq]), X ring chromosome X (XrX), with Y material, and "other". RESULTS: Ninety patients, with mean age 11.9years (±4.8years) at first ENT consultation, were included: 29% showed tympanic abnormality on otoscopy, 21% had hearing loss, 24% had history of recurrent acute otitis media; 18% had undergone adenoidectomy, 24% T-tube insertion, and 5.6% tympanoplasty. No particular karyotype was associated with higher risk of hearing loss or acute otitis media. CONCLUSION: Patients with TS showed high prevalence of pediatric otologic disorders; they therefore require close and prolonged ENT follow-up.

Natural history and management of congenital hypothyroidism with in situ thyroid gland.

BACKGROUND/OBJECTIVE: Normally sited glands account for increasing congenital hypothyroidism (CH). Mechanisms often remain unknown. To report the incidence of CH with in situ thyroid gland (ISTG) and describe the natural history of the disease without known etiology. METHOD: Clinical, biochemical and imaging data at diagnosis were retrospectively analyzed in 285 children positively screened for CH in Ile-de-France between 2005 and 2008. If treatment was discontinued, management of hormonal substitution and follow-up of biochemical thyroid function was performed. RESULTS: 93 full-term CH neonates displayed ISTG (40.6%), including 50 with unexplained mechanism. Follow-up data were available in 32 of them. Therapy was withdrawn from 20 children at a median age of 23.5 months (6-66), among whom 18 remained still untreated over a median duration of 15.3 months (4.4-29.6). In 11 children, levothyroxine (L-T4) dosage was increased over time to maintain biochemical euthyroidism. No statistical differences in initial TSH or FT4 levels, iodine status or birth weight were found between children with transient and permanent hypothyroidism. CONCLUSION: Withdrawal of L-T4 substitution was feasible in 56.2% of full-term children with CH with ISTG but unexplained mechanism, emphasizing the need for systematic therapy withdrawal. However, further studies are warranted to standardize withdrawal protocol.

[Turner Syndrome: what's new in medical care?]. / Le syndrome de Turner : quoi de neuf dans la prise en charge ?

Turner syndrome is a rare genetic disorder, affecting approximately one in 2500 live-born female, due to total or partial absence of the X chromosome. Typical clinical features are short stature and premature ovarian failure and less constantly phenotypic particularities such as congenital malformations, acquired cardiovascular, otological (hearing impairment), autoimmune and metabolic pathologies. The phenotype is highly variable with slight or even normal phenotype. Several studies have shown that growth hormone treatment improves adult height. The possibility of pregnancies after oocyte donation highlights the high risk of these pregnancies requiring a careful follow-up, especially in terms of cardiovascular issues. Although the quality of life seems similar to the normal population, the presence of cardiovascular and otological diseases, and delayed feminisation are associated with an impaired quality of life. Early diagnosis and regular screening for potentials associated complications are essential in the medical follow-up of these patients. The recent publication of recommendations should lead to an optimization and harmonisation of the medical practices and follow-up from paediatric age to adulthood, a lowering morbidity and self-esteem improvement. The interest of ovarian cryopreservation at an early age in these patients is under investigation.

Medullary thyroid carcinoma identified within the first year of life in children with hereditary multiple endocrine neoplasia type 2A (codon 634) and 2B.

CONTEXT: Early prophylactic thyroidectomy in patients with multiple endocrine neoplasia (MEN) type 2 offers the best chance for a normal life expectancy. OBJECTIVE: To analyze the results of thyroidectomy performed during the first year of life in six patients with MEN 2A (codon 634) or MEN 2B (codon 918) syndrome. DESIGN AND SETTING: A university hospital-based prospective study from 2001 to 2008. SUBJECTS AND METHODS: Six family members affected either by MEN 2A (n=3) or MEN 2B (n=3) syndrome were identified through neonatal genetic screening. RESULTS: Total thyroidectomy was performed at a median age of 0.8 year in the six patients, with central lymph node dissection in five. Bilateral millimetric medullary thyroid carcinoma (MTC) was found in all patients, with a unilateral lymph node micrometastasis in two of the three MEN 2B patients. Before thyroidectomy, MEN 2B patients had much higher basal serum calcitonin levels than those with MEN 2A and controls. After thyroidectomy, with a median follow-up of 3.3 years, the six patients had no evidence of persistent MTC. CONCLUSION: Bilateral millimetric MTC may be present during the first year of life in these patients, with lymph node metastases also occurring in MEN 2B patients. These results support a total thyroidectomy at the age of about one year in MEN 2A (codon 634) children with an abnormal serum calcitonin level, and a total thyroidectomy with central neck dissection within the first weeks of life in MEN 2B patients.

Bilateral anorchia in infancy: occurence of micropenis and the effect of testosterone treatment.

OBJECTIVE: To analyze the clinical and histological findings in boys with bilateral anorchia and the response to testosterone treatment on penis length. STUDY DESIGN: Patients were divided into two groups according to the absence (group A, n = 29) or the presence (group B, n = 26) of palpable intrascrotal or inguinal mass at first clinical examination. RESULTS: A micropenis was found in 46% of patients (n = 24) with a similar proportion in both groups. Testosterone treatment induced a mean penis length gain of 1.9 +/- 1.3 SDS (standard deviation score). However, micropenis persisted in six patients. Histological examination (n = 18) confirmed the absence of any testicular structure with deferent ducts being present unilaterally or bilaterally in all but three patients. In these three patients, a hemorrhagic testis, probably as a result of a mechanical torsion, was found. CONCLUSIONS: The presence of isolated micropenis in almost half of patients with bilateral anorchia strongly suggests that the testicular damage frequently occurs during the second half of gestation after male sexual differentiation. In most cases, testosterone treatment stimulates the penile growth. Although the pathogenesis of bilateral anorchia may be heterogeneous, our study suggests that gonads may have been functionally abnormal before they disappeared, and suggests that some patients have an intrinsic endocrine disorder.