Turner syndrome: French National Diagnosis and Care Protocol (NDCP; National Diagnosis and Care Protocol)

Turner syndrome (TS; ORPHA 881) is a rare condition in which all or part of one X chromosome is absent from some or all cells. It affects approximately one in every 1/2500 liveborn girls. The most frequently observed karyotypes are 45,X (40–50%) and the 45,X/46,XX mosaic karyotype (15–25%). Karyotypes with an X isochromosome (45,X/46,isoXq or 45,X/46,isoXp), a Y chromosome, X ring chromosome or deletions of the X chromosome are less frequent. The objective of the French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins) is to provide health professionals with information about the optimal management and care for patients, based on a critical literature review and multidisciplinary expert consensus. The PNDS, written by members of the French National Reference Center for Rare Growth and Developmental Endocrine disorders, is available from the French Health Authority website. Turner Syndrome is associated with several phenotypic conditions and a higher risk of comorbidity. The most frequently reported features are growth retardation with short adult stature and gonadal dysgenesis. TS may be associated with various congenital (heart and kidney) or acquired diseases (autoimmune thyroid disease, celiac disease, hearing loss, overweight/obesity, glucose intolerance/type 2 diabetes, dyslipidemia, cardiovascular complications and liver dysfunction). Most of the clinical traits of TS are due to the haploinsufficiency of various genes on the X chromosome, particularly those in the pseudoautosomal regions (PAR 1 and PAR 2), which normally escape the physiological process of X inactivation, although other regions may also be implicated. The management of patients with TS requires collaboration between several healthcare providers. The attending physician, in collaboration with the national care network, will ensure that the patient receives optimal care through regular follow-up and screening. The various elements of this PNDS are designed to provide such support.

Position statement on the diagnosis and management of premature/primary ovarian insufficiency (except Turner Syndrome)

Premature ovarian insufficiency (POI) is a rare pathology affecting 1-2% of under-40 year-old women, 1 in 1000 under-30 year-olds and 1 in 10,000 under-20 year-olds. There are multiple etiologies, which can be classified as primary (chromosomal, genetic, auto-immune) and secondary or iatrogenic (surgical, or secondary to chemotherapy and/or radiotherapy). Despite important progress in genetics, more than 60% of cases of primary POI still have no identifiable etiology; these cases are known as idiopathic POI. POI is defined by the association of 1 clinical and 1 biological criterion: primary or secondary amenorrhea or spaniomenorrhea of>4 months with onset before 40 year of age, and elevated follicle-stimulating hormone (FSH)>25IU/L on 2 assays at>4 weeks' interval. Estradiol level is low, and anti-Müllerian hormone (AMH) levels have usually collapsed. Initial etiological work-up comprises auto-immune assessment, karyotype, FMR1 premutation screening and gene-panel study. If all of these are normal, the patient and parents may be offered genome-wide analysis under the "France Génomique" project. The term ovarian insufficiency suggests that the dysfunction is not necessarily definitive. In some cases, ovarian function may fluctuate, and spontaneous pregnancy is possible in around 6% of cases. In confirmed POI, hormone replacement therapy is to be recommended at least up to the physiological menopause age of 51 years. Management in a rare diseases center may be proposed.

Screening of a Large Cohort of Asymptomatic SDHx Mutation Carriers in Routine Practice

CONTEXT

When an SDHx mutation is identified in a patient with a pheochromocytoma (PCC) or a paraganglioma (PGL), predictive genetic testing can detect mutation carriers that would benefit from screening protocols.

OBJECTIVE

To define the tumor detection rate in a large cohort of asymptomatic SDHX mutation carriers.

DESIGN AND SETTING

Retrospective multicentric study in 6 referral centers.

PATIENTS

Between 2005 and 2019, 249 asymptomatic SDHx (171 SDHB, 31 SDHC, 47 SDHD) mutation carriers, with at least 1 imaging work-up were enrolled.

RESULTS

Initial work-up, including anatomical (98% of subjects [97-100% according to center]) and/or functional imaging (67% [14-90%]) detected 48 tumors in 40 patients. After a negative initial work-up, 124 patients benefited from 1 to 9 subsequent follow-up assessments (mean: 1.9 per patient), with a median follow-up time of 5 (1-13) years. Anatomical (86% [49-100 %]) and/or functional imaging (36% [7-60 %]) identified 10 new tumors (mean size: 16 mm [4-50]) in 10 patients. Altogether, 58 tumors (55 paraganglioma [PGL], including 45 head and neck PGL, 2 pheochromocytoma [PCC], 1 gastrointestinal stromal tumor [GIST]), were detected in 50 patients (22 [13%] SDHB, 1 [3.2%] SDHC, and 27 [57%] SDHD), with a median age of 41 years old [11-86], 76% without catecholamine secretion and 80% during initial imaging work-up.

CONCLUSIONS

Imaging screening enabled detection of tumors in 20% of asymptomatic SDHx mutation carriers, with a higher detection rate in SDHD (57%) than in SDHB (13%) and SDHC (3%) mutation carriers, arguing for a gene-by-gene approach. Prospective studies using well-defined protocols are needed to obtain strong and useful data.

Factors Affecting Loss to Follow-Up in Children and Adolescents with Chronic Endocrine Conditions

OBJECTIVE

Most children with endocrine diseases require long-term continuity of care. We investigated the prevalence of loss to follow-up (LTFU) in pediatric patients with chronic endocrine diseases and the risk factors associated with LTFU.

METHODS

This observational cohort study included all children with chronic endocrine diseases included in the database of a single academic pediatric care center over a period of 8 years. LTFU was defined as a lack of attendance at clinical visits for over 2 years, for unknown reasons.

RESULTS

LTFU was recorded for 154 of the 1,067 patients included (14%). Median age at diagnosis was 5.8 (0.3-11.8) vs. 1.2 (0.0-6.9) years, and age at last visit was 14.1 (9.7-16.1) vs. 11.7 (6.1-15.8) years, for the LTFU and no-LTFU groups, respectively. In multivariate analysis, the risk of LTFU increased with age at diagnosis (OR 1.18; 95% CI 1.12-1.24) and was higher for patients diagnosed before 2006 (vs. after 2006; OR 4.80; 95% CI 3.00-7.66), with fewer visits in the last 3 years (OR 0.72; 95% CI 0.65-0.80; p < 0.0001) and a lower health insurance classification (OR 1.79; 95% CI 1.10-2.89; p = 0.02). The risk of LTFU was higher for patients with isolated growth hormone deficiency than for those with other endocrine conditions, such as multiple pituitary deficiencies, hypogonadotropic hypogonadism, Turner syndrome, or thyroid, adrenal, or gonadal disorders (OR 5.24; 95% CI 1.13-24.37; p = 0.03).

CONCLUSION

This study provides the first epidemiological data for LTFU in children and adolescents with chronic endocrine diseases. It should facilitate the targeting of interventions to improve adherence to medical care and healthcare organization during the pediatric period.

Positive Impact of Genetic Test on the Management and Outcome of Patients With Paraganglioma and/or Pheochromocytoma

CONTEXT

Pheochromocytomas and paragangliomas (PPGLs) are characterized by a strong genetic component, with up to 40% of patients carrying a germline mutation in a PPGL susceptibility gene. International guidelines recommend that genetic screening be proposed to all patients with PPGL.

OBJECTIVE

Our objective was to evaluate how a positive genetic test impacts the management and outcome of patients with SDHx or VHL-related PPGL.

DESIGN

We performed a multicentric retrospective study involving 221 propositi carrying an SDHB, SDHD, SDHC, or VHL germline mutation. Patients were divided into two groups: genetic patients, who were informed of their genetic status within the year following the first PPGL diagnosis, and historic patients, who only benefited from the genetic test several years after initial PPGL diagnosis.

RESULTS

Genetic patients had better follow-up than historic patients, with a greater number of examinations and a reduced number of patients lost to follow-up (9.6% vs 72%, respectively). During follow-up, smaller (18.7 vs 27.6 mm; P = 0.0128) new PPGLs and metastases as well as lower metastatic spread were observed in genetic patients. Of note, these differences were reversed in the historic cohort after genetic testing. Genetic patients who developed metachronous metastases had a better 5-year survival rate than historic patients (P = 0.0127).

CONCLUSION

Altogether, our data suggest that early knowledge of genetic status had a positive impact on the management and clinical outcome of patients with a germline SDHx or VHL mutation.

Should 45,X/46,XY boys with no or mild anomaly of external genitalia be investigated and followed up?

OBJECTIVE

Few studies of patients with a 45,X/46,XY mosaicism have considered those with normal male phenotype. The purpose of this study was to evaluate the clinical outcome of 45,X/46,XY boys born with normal or minor abnormalities of external genitalia, notably in terms of growth and pubertal development.

METHODS

Retrospective longitudinal study of 40 patients followed between 1982 and 2017 in France.

RESULTS

Twenty patients had a prenatal diagnosis, whereas 20 patients had a postnatal diagnosis, mainly for short stature. Most patients had stunted growth, with abnormal growth spurt during puberty and a mean adult height of 158 ± 7.6 cm, i.e. -2.3 DS with correction for target height. Seventy percent of patients presented Turner-like syndrome features including cardiac (6/23 patients investigated) and renal malformations (3/19 patients investigated). Twenty-two patients had minor abnormalities of external genitalia. One patient developed a testicular embryonic carcinoma, suggesting evidence of partial gonadal dysgenesis. Moreover, puberty occurred spontaneously in 93% of patients but 71% (n = 5) of those evaluated at the end of puberty presented signs of declined Sertoli cell function (low inhibin B levels and increased FSH levels).

CONCLUSION

This study emphasizes the need to identify and follow-up 45,X/46,XY patients born with normal male phenotype until adulthood, as they present similar prognosis than those born with severe genital anomalies. Currently, most patients are diagnosed in adulthood with azoospermia, consistent with our observations of decreased testicular function at the end of puberty. Early management of these patients may lead to fertility preservation strategies.

Mutations in BOREALIN cause thyroid dysgenesis

Congenital hypothyroidism is the most common neonatal endocrine disorder and is primarily caused by developmental abnormalities otherwise known as thyroid dysgenesis (TD). We performed whole exome sequencing (WES) in a consanguineous family with TD and subsequently sequenced a cohort of 134 probands with TD to identify genetic factors predisposing to the disease. We identified the novel missense mutations p.S148F, p.R114Q and p.L177W in the BOREALIN gene in TD-affected families. Borealin is a major component of the Chromosomal Passenger Complex (CPC) with well-known functions in mitosis. Further analysis of the missense mutations showed no apparent effects on mitosis. In contrast, expression of the mutants in human thyrocytes resulted in defects in adhesion and migration with corresponding changes in gene expression suggesting others functions for this mitotic protein. These results were well correlated with the same gene expression pattern analysed in the thyroid tissue of the patient with BOREALIN-p.R114W. These studies open new avenues in the genetics of TD in humans.

A 6-Month Trial of the Efficacy and Safety of Triptorelin Pamoate (11.25 mg) Every 3 Months in Children with Precocious Puberty: A Retrospective Comparison with Triptorelin Acetate

BACKGROUND/AIMS

To evaluate the efficacy and safety of a triptorelin pamoate (11.25 mg) 3-month formulation in the management of central precocious puberty (CPP) (TP Study) and to retrospectively compare it with a triptorelin acetate (11.25 mg) 3-month formulation (TA Study).

METHODS

We conducted two phase III, multicentre, single-stage, non-comparative, open-label studies. In the TP Study, patients with CPP received an intramuscular injection of triptorelin pamoate 11.25 mg at baseline and 3 months after baseline. Hormonal changes as well as safety and efficacy endpoints were measured at baseline, 3 months, and 6 months.

RESULTS

The baseline characteristics of the 37 patients in the TP Study were similar to those of the TA Study population. A suppressed luteinising hormone (LH) response (LH peak ≤3 IU/l) to the gonadotrophin-releasing hormone test at 3 months (primary endpoint) occurred in 83.8 and 82.8% of the cases in the TP and the TA Study, respectively. At 6 months, a suppressed LH response occurred in 86.5 and 96.8% of the cases in the TP and the TA Study, respectively. Pubertal development was slowed in both studies. Adverse events were mild to moderate and resolved without sequelae in the TP Study.

CONCLUSION

Triptorelin pamoate 11.25 mg administered at 3-month intervals is an effective and well-tolerated treatment in patients with CPP. The efficacy and safety profiles appear similar to those reported in the literature for triptorelin acetate 11.25 mg. © 2016 S. Karger AG, Basel.

Claudin-16 Deficiency Impairs Tight Junction Function in Ameloblasts, Leading to Abnormal Enamel Formation

Claudin-16 protein (CLDN16) is a component of tight junctions (TJ) with a restrictive distribution so far demonstrated mainly in the kidney. Here, we demonstrate the expression of CLDN16 also in the tooth germ and show that claudin-16 gene (CLDN16) mutations result in amelogenesis imperfecta (AI) in the 5 studied patients with familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC). To investigate the role of CLDN16 in tooth formation, we studied a murine model of FHHNC and showed that CLDN16 deficiency led to altered secretory ameloblast TJ structure, lowering of extracellular pH in the forming enamel matrix, and abnormal enamel matrix protein processing, resulting in an enamel phenotype closely resembling human AI. This study unravels an association of FHHNC owing to CLDN16 mutations with AI, which is directly related to the loss of function of CLDN16 during amelogenesis. Overall, this study indicates for the first time the importance of a TJ protein in tooth formation and underlines the need to establish a specific dental follow-up for these patients.

X-chromosome gene dosage as a determinant of impaired pre and postnatal growth and adult height in Turner syndrome

OBJECTIVE

Short stature is a key aspect of the phenotype of patients with Turner syndrome (TS). SHOX haploinsufficiency is responsible for about two-thirds of the height deficit. The aim was to investigate the effect of X-chromosome gene dosage on anthropometric parameters at birth, spontaneous height, and adult height (AH) after growth hormone (GH) treatment.

DESIGN

We conducted a national observational multicenter study.

METHODS

Birth parameter SDS for gestational age, height, and AH before and after GH treatment respectively, and height deficit with respect to target height (SDS) were classified by karyotype subgroup in a cohort of 1501 patients with TS: 45,X (36%), isoXq (19%), 45,X/46,XX (15%), XrX (7%), presence of Y (6%), or other karyotypes (17%).

RESULTS

Birth weight, length (P<0.0001), and head circumference (P<0.001), height and height deficit with respect to target height (SDS) before GH treatment, at a median age of 8.8 (5.3-11.8) years and after adjustment for age and correction for multiple testing (P<0.0001), and AH deficit with respect to target height at a median age of 19.3 (18.0-21.8) years and with additional adjustment for dose and duration of GH treatment (P=0.006), were significantly associated with karyotype subgroup. Growth retardation tended to be more severe in patients with XrX, isoXq, and, to a lesser extent, 45,X karyotypes than in patients with 45,X/46,XX karyotypes or a Y chromosome.

CONCLUSION

These data suggest that haploinsufficiency for an unknown Xp gene increases the risk of fetal and postnatal growth deficit and short AH with respect to target height after GH therapy.

Mutations in the maternally imprinted gene MKRN3 are common in familial central precocious puberty

CONTEXT AND OBJECTIVE

Idiopathic central precocious puberty (iCPP) is defined as early activation of the hypothalamic-pituitary-gonadal axis in the absence of identifiable central lesions. Mutations of the makorin RING finger 3 (MKRN3) gene are associated with iCPP. We aimed to assess the frequency of MKRN3 mutations in iCPP and to compare the phenotypes of patients with and without MKRN3 mutations.

DESIGN

An observational study was carried out on patients recruited at pediatric hospitals in France and Italy. Forty-six index CPP cases were screened for mutations in the MKRN3 coding sequence: 28 index cases of familial cases and 18 cases did not report any familial history of CPP. The endocrine phenotype was compared between MKRN3 mutated and non-mutated patients.

RESULTS

MKRN3 mutations were identified in one sporadic and 13 familial cases. We identified five new heterozygous missense mutations predicted to be deleterious for protein function and two frameshift mutations, one new and the other recurrent, predicted to result in truncated proteins. Age at puberty onset varied very little among patients with MKRN3 mutations and puberty occurred earlier in these patients than in those without MKRN3 mutations (6.0 years (5.4-6.0) vs 7.0 years (6.0-7.0), P=0.01).

CONCLUSIONS

MKRN3 mutations are common in familial iCPP. MKRN3 is one of the gatekeepers of the postnatal activation of the gonadotropic axis.

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.

Triiodothyronine-predominant Graves' disease in childhood: detection and therapeutic implications

OBJECTIVE

To assess in a pediatric population, the clinical characteristics and management of triiodothyronine-predominant Graves' disease (T3-P-GD), a rare condition well known in adults, but not previously described in children.

DESIGN

We conducted a university hospital-based observational study.

METHODS

All patients with GD followed for more than 1 year between 2003 and 2013 (n=60) were included. T3-P-GD (group I) was defined as high free T3 (fT3) concentration (>8.0 pmol/l) associated with a normal free thyroxine (fT4) concentration and undetectable TSH more than 1 month after the initiation of antithyroid drug (ATD) treatment. Group II contained patients with classical GD without T3-P-GD.

RESULTS

Eight (13%) of the patients were found to have T3-P-GD, a median of 6.3 (3.0-10.5) months after initial diagnosis (n=4) or 2.8 (2.0-11.9) months after the first relapse after treatment discontinuation (n=4). At GD diagnosis, group I patients were more likely to be younger (6.8 (4.3-11.0) vs 10.7 (7.2-13.7) years) and had more severe disease than group II patients, with higher serum TSH receptor autoantibodies (TRAb) levels: 40 (31-69) vs 17 (8-25) IU/l, P<0.04, and with slightly higher serum fT4 (92 (64-99) vs 63 (44-83) pmol/l) and fT3 (31 (30-46) vs 25 (17-31) pmol/l) concentrations. During the 3 years following T3-P-GD diagnosis, a double dose of ATD was required and median serum fT4:fT3 ratio remained lower in group I than in group II.

CONCLUSION

Severe hyperthyroidism, with particularly high TRAb concentrations at diagnosis, may facilitate the identification of patients requiring regular serum fT3 determinations and potentially needing higher doses of ATD dosage during follow-up.

Cardiovascular findings and management in Turner syndrome: insights from a French cohort

OBJECTIVE

Congenital cardiovascular malformations and aortic dilatation are frequent in patients with Turner syndrome (TS). The objective of this study was to investigate the cardiovascular findings and management in a large cohort of patients, including children and adults.

DESIGN/METHODS

We recruited 336 patients with TS from a network of tertiary centers. We reviewed their files, checking for cardiovascular events, cardiac valve abnormalities, and aortic diameters indexed to body surface area (BSA) from magnetic resonance imaging (n=110) or echocardiography (n=300).

RESULTS

Informative cardiovascular data were available for only 233 patients. Vascular surgery was reported in 7.4% of the cohort. The first cause of surgery was aortic coarctation, detected in 6.9% at a median age of 9.5 (range: 0-60) years. Bicuspid aortic valve (BAV) was detected in 21% at a median age of 20 years (25th-75th percentiles: 15-30). At least one aortic diameter exceeded 32 mm in 12% of the cohort. This was detected at a median age of 19 (7-30) years. When indexed to BSA, at least one aortic diameter exceeded 20 mm/m(2) in 39% of the cohort.

CONCLUSION

Our study shows that cardiovascular monitoring for TS patients is currently insufficient in France. BAV is present at birth, but often remains undiagnosed until later in life. Therefore, improved management in cardiovascular monitoring is required and a more systematic approach should be taken.

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.

Dental agenesis in Kallmann syndrome individuals with FGFR1 mutations

BACKGROUND

Kallmann syndrome (KS) is a rare genetic disorder characterised by central hypogonadism with a lack of sense of smell and in some cases renal aplasia, deafness, syndactyly, cleft lip/palate, and dental agenesis. To date, five genes for KS have been identified: KAL1, located on the X chromosome, and FGFR1, PROKR2, PROK2 and FGF8, which are involved in autosomally transmitted forms of KS.

AIM

The study characterised the dental ageneses of individuals with KS associated with mutations in the FGFR1 gene.

DESIGN

Six individuals displaying dental agenesis were included. Clinical and radiological dental evaluations as well as medical anamneses were carried out.

RESULTS

Microdontia, screwdriver-shaped mandibular incisors, thin molar roots, and patterns of dental agenesis in both dentitions were observed. One to nine teeth were missing, most frequently, in descending order, lateral mandibular incisors, second premolars of upper and lower jaws, and lateral maxillary incisors. The pattern of dental agenesis is associated with four new mutations in the FGFR1 gene.

CONCLUSION

Dental agenesis may be a clinical feature of Kallmann syndrome caused by a mutation in the FGFR1 gene. These findings highlight the role that odontologists can play in the early diagnosis and treatment of gonadotropic deficiency.

Steroidogenic factor-1 (SF-1) gene mutation as a frequent cause of primary amenorrhea in 46,XY female adolescents with low testosterone concentration

BACKGROUND

Primary amenorrhea due to 46,XY disorders of sex differentiation (DSD) is a frequent reason for consultation in endocrine and gynecology clinics. Among the genetic causes of low-testosterone primary amenorrhea due to 46,XY DSD, SRY gene is reported to be frequently involved, but other genes, such as SF1 and WT1, have never been studied for their prevalence.

METHODS

We directly sequenced SRY, SF1 and WT1 genes in 15 adolescent girls with primary amenorrhea, low testosterone concentration, and XY karyotype, to determine the prevalence of mutations. We also analyzed the LH receptor gene in patients with high LH and normal FSH concentrations.

RESULTS

Among the 15 adolescents with primary amenorrhea and low testosterone concentration, we identified two new SRY mutations, five new SF1 mutations and one new LH receptor gene mutation. Our study confirms the 10-15% prevalence of SRY mutations and shows the high prevalence (33%) of SF1 abnormalities in primary amenorrhea due to 46,XY DSD with low plasma testosterone concentration.

CONCLUSIONS

The genetic analysis of low-testosterone primary amenorrhea is complex as several factors may be involved. This work underlines the need to systematically analyze the SF1 sequence in girls with primary amenorrhea due to 46,XY DSD and low testosterone, as well as in newborns with 46,XY DSD.

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.

[Precocious pubertal]

Precocious pubertal is frequent and should lead to a rigorous evaluation. It is important to precisely evaluate the timing of pubertal development, and to search for an hypothalamic lesion in cases of central precocious puberty. It is also important to recognize that many cases of precocious puberty will not progress and therefore do not need treatment. When central precocious puberty has been confirmed, GnRH agonists should be considered. Management issues, as well as long term results of these treatments are presented.

Mutational analysis of steroidogenic factor 1 (NR5a1) in 24 boys with bilateral anorchia: a French collaborative study

BACKGROUND Steroidogenic factor 1 (SF1/AdBP4/FTZF1, NR5A1) is a nuclear receptor transcription factor that plays a key role in regulating adrenal and gonadal development, steroidogenesis and reproduction. Recently, haploinsufficiency of SF1 has been described in several 46,XY individuals with mild gonadal dysgenesis and impaired androgenization, but normal adrenal function, suggesting that dosage-sensitive or domain-specific effects of SF1 action are important in human testicular development and function. Our objective was to investigate whether partial defects in SF1 function might be associated with milder male reproductive phenotypes, such as bilateral anorchia ('vanishing testis syndrome') and micropenis. METHODS This study involved mutational analysis of NR5A1 in 24 individuals with bilateral anorchia and micropenis from the French Collaborative Anorchia study, as well as in vitro functional studies of SF1-dependent transcriptional activation and computer modeling. RESULTS A novel heterozygous missense mutation (V355M) in SF1 was found in one boy with a micropenis and testicular regression syndrome. This non-synonymous change was found to affect a highly conserved amino acid within helix 7 of the ligand-binding domain of SF1. This V355M mutation did not affect stability or nuclear localization, but did result in an approximately 50% reduction in SF1 activity in several different assay systems. CONCLUSIONS In conclusion, heterozygous partial loss of function mutations in SF1 may be associated with bilateral anorchia ('vanishing testis syndrome') and micropenis in humans.

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.

Paediatric phenotype of Kallmann syndrome due to mutations of fibroblast growth factor receptor 1 (FGFR1)

Kallmann syndrome characterised by hypogonadotropic hypogonadism (HH) and anosmia is genetically heterogeneous with X-linked, autosomal dominant and autosomal recessive forms. The autosomal dominant form due to loss of function mutation in the fibroblast growth factor receptor 1 (FGFR1) accounts for about 10% of cases. We report here three paediatric cases of Kallmann syndrome with unusual phenotype in two unrelated patients with severe ear anomalies (hypoplasia or agenesis of external ear) associated with classical features, such as cleft palate, dental agenesis, syndactylia, micropenis and cryptorchidism. We found de novo mutation in these two patients (Cys178Ser and Arg622Gly, respectively), and one inherited Arg622Gln mutation with intrafamilial variable phenotype. These genotype-phenotype correlations indicate that paediatric phenotypic expression of FGFR1 loss of function mutations is highly variable, the severity of the oro-facial malformations at birth does not predict gonadotropic function at the puberty and that de novo mutations of FGFR1 are relatively frequent.

Presence of magnetic resonance imaging abnormalities of the hypothalamic-pituitary axis is a significant determinant of the first 3 years growth response to human growth hormone treatment in prepubertal children with nonacquired growth hormone deficiency

OBJECTIVE

The factors influencing the highly variable growth response to GH treatment in GH-deficient children are not fully understood. Despite a real benefit with GH treatment in term of growth response, most of these patients attain a mean adult height below their target height and the strategy to optimise final height has to be improved. The aim of this study was to investigate whether the presence of congenital abnormalities of the hypothalamic-pituitary axis on magnetic resonance imaging (MRI) could be a determinant of the growth response in nonacquired prepubertal GH-deficient children, and to identify which pretreatment variables most significantly affect the first 3 years growth response to human GH (hGH) therapy.

PATIENTS AND METHODS

The growth response to hGH treatment (0.55 +/- 0.1 IU/kg/week) was evaluated in 69 prepubertal children with nonacquired GH deficiency, according to the absence (group A: chronological age = 4.8 +/- 2.4 years, n= 37) or the presence (group B: chronological age = 3.4 +/- 2.7 years, n= 32) of developmental abnormalities on cerebral magnetic imaging and, after controlling for GH dose, age, height, height velocity (SDS) and body mass index at start of treatment, maximum stimulated GH peak concentration, GH deficiency type (isolated vs. multiple deficiency), parental height, size at birth and sex.

RESULTS

After 3 years of treatment, the mean height gain was significantly higher in patients of group B vs. group A (2.2 +/- 1.3 vs. 1.6 +/- 1 SDS; P < 0.05). In a multiple regression analysis, age (r2 = 0.19, negatively correlated), pretreatment height velocity (r2 = 0.11, negatively correlated), GH dose (r2 = 0.05, positively correlated) and presence of magnetic resonance imaging developmental abnormalities (r2 = 0.05, positively correlated) were found to significantly explain 40% of the variability in growth response.

CONCLUSIONS

The detection of congenital abnormalities in the hypothalamic-pituitary area on MRI is more important than the level of maximum stimulated GH to predict the growth response to hGH treatment in prepubertal nonacquired GH-deficient children. Although the persistence of GH deficiency remains to be confirmed during follow-up by reassessment of GH secretion in isolated GH-deficient patients with normal MRI findings, further studies are needed to evaluate whether an increased hGH dose in these patients could improve long-term growth response.