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Charles Sultan

Publications and source records attributed to Charles Sultan.

At least 19 recordsLinked to original sources
PubMed2007

Heterozygous missense mutations in steroidogenic factor 1 (SF1/Ad4BP, NR5A1) are associated with 46,XY disorders of sex development with normal adrenal function.

CONTEXT: 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. Targeted deletion of Nr5a1 (Sf1) in the mouse results in adrenal and gonadal agenesis, XY sex-reversal, and persistent Müllerian structures in males. Consistent with the murine phenotype, human mutations in SF1 were described initially in two 46,XY individuals with female external genitalia, Müllerian structures (uterus), and primary adrenal failure. OBJECTIVE: Given recent case reports of haploinsufficiency of SF1 affecting testicular function in humans, we aimed to identify SF1 mutations in a cohort of individuals with a phenotypic spectrum of 46,XY gonadal dysgenesis/impaired androgenization (now termed 46,XY disorders of sex development) with normal adrenal function. METHODS AND PATIENTS: The study included mutational analysis of NR5A1 in 30 individuals with 46,XY disorders of sex development, followed by functional studies of SF1 activity. RESULTS: Heterozygous missense mutations in NR5A1 were found in four individuals (four of 30, 13%) with this phenotype. These mutations (V15M, M78I, G91S, L437Q) were shown to impair transcriptional activation through abnormal DNA binding (V15M, M78I, G91S), altered subnuclear localization (V15M, M78I), or disruption of the putative ligand-binding pocket (L437Q). Two mutations appeared to be de novo or germline changes. The other two mutations appeared to be inherited in a sex-limited dominant manner because the mother is heterozygous for the change. CONCLUSIONS: These studies demonstrate that SF1 mutations are more frequent than previously suspected causes of impaired fetal and postnatal testicular function in 46,XY individuals.

Adolescent↗
PubMed2006

Mild surfection of neural cells, especially motoneurons, in primary culture and cell lines.

Of all cell types, motoneurons (MNs), are possibly the most difficult to maintain in culture, since their development and survival is conditioned by many factors that are still in the course of identification. This may also be the reason why they are difficult to transfect. We succeed to transfect these fragile cells with lipoplex [DOTAP:PC (10:1)-pGFP]-precoated coverslips. Here, we report that this original method, also termed 'surfection' does not perturbate MN development and survival while giving important transfection yield (15%). Lipofectamine 2000 and other well-known auxiliary lipids (DOPE, Chol) give lower surfection yields. The use of (DOTAP:PC)-based lipid vector also can be extended to several neural and non-neural cell lines with appreciable transfection yield such as a glial cell line (GCL) derived from rat spinal cord (65%), HeLa S3 (60%), COS-7 (30%) and HEK 293 cells (20%). The efficiency of DOTAP:PC (10:1) and Lipofectamine 2000 vectors in our surfection method are compared on standard HeLa S3 cell lines. Lipofectamine 2000 (72%) is slightly better than DOTAP:PC (10:1) (60%). However, the surfection method improved the efficiency of Lipofectamine 2000 itself (72%) as compared to the classical (62%) approach. In summary we have developed an original standard surfection protocol for both MN primary cultures and cell lines, thus simplifying laboratory practice; moreover, Lipofectamine 2000 used in this surfection method is more efficient for the cell lines than the manufacturer-recommended method. We emphasize that our method particularly spares fragile cells like MNs from injure and therefore, might be applied to other fragile cell type in primary cultures.

Animals↗
PubMed2006

Unexpected mosaicism of R201H-GNAS1 mutant-bearing cells in the testes underlie macro-orchidism without sexual precocity in McCune-Albright syndrome.

McCune-Albright syndrome (MAS), usually presenting with polyostotic bone dysplasia, café-au-lait skin lesions and sexual precocity, results from a somatic activating mutation of the GNAS1 gene, which encodes the Gs-alpha protein involved in signalling of several G-protein-coupled receptors. The clinical spectrum depends on tissue distribution of mutant-bearing cells. Sexual precocity has been ascribed to the occurrence of a mutant GNAS1 allele in the gonadal anlage, from which all somatic cells of the differentiated gonads arise. In boys, precocious activation of Leydig cell androgen secretion results in pubertal spermatogenesis, leading to testicular enlargement, and in the development of secondary sex characteristics. However, sexual precocity is rare in MAS males while isolated testicular enlargement is frequently observed. We recently reported the case of a boy with macro-orchidism and signs of Sertoli cell hyperactivity but no signs of hyperandrogenism, which was unexpected since Gs-alpha is functional in both Sertoli and Leydig cells. To understand its pathophysiology, we microdissected an available testicular biopsy to separate Sertoli from Leydig cells. The R201H-GNAS1 allele was present only in Sertoli cells, resulting in isolated Sertoli cell hyperfunction, evidenced by increased AMH expression and cell hyperplasia leading to prepubertal macro-orchidism, with no signs of Leydig cell activation. The different early embryologic origin of precursors contributing to Sertoli and Leydig cell lineages may underlie the differential existence of the mutated GNAS1 gene. Lack of occurrence of the mutation in Leydig cells may explain why sexual precocity is rarely observed in boys with MAS.

Base Sequence↗
PubMed2006

Association between androgen receptor gene polymorphism and bone density in older women using hormone replacement therapy.

OBJECTIVE: The objective of this study was to investigate the relationship between bone mineral density (BMD) and both CAG repeat polymorphism of the androgen receptor (AR) gene and skewed X chromosome inactivation (SI) in postmenopausal women. METHODS: BMD was measured by DEXA. Both the number and the X-weighted biallelic mean of the CAG repeats of AR were analysed by PCR, before and after DNA digestion with methylation-sensitive HpaII in 192 healthy Caucasian postmenopausal women. RESULTS: The number of CAG repeats ranged from 10 to 34, with a median value of 22. CAG)(n< or =22) and CAG)(n> or =23) alleles were designated as short and long alleles, respectively. In women using hormone replacement therapy (HRT) (n=81), lumbar spine BMD was significantly lower, and femoral neck and total body BMD marginally lower in those with long-long alleles when compared with those with other genotypes. SI (> or =80%) was observed in 24% of the women and was not associated with BMD. In women using HRT, femoral neck BMD was significantly lower, and lumbar spine and total body BMD marginally lower in those whose X-weighted CAG repeat biallelic was greater than 22.59 (median value) when compared to other genotypes. These results were not found in women not using HRT. CONCLUSION: In conclusion, our results suggest that BMD may be associated with AR gene polymorphism in postmenopausal women using HRT but not with SI. Further studies are needed to investigate the mechanisms of the interaction between HRT, BMD and AR found in the present study.

Absorptiometry, Photon↗
PubMed2006

Activating mutations of the stimulatory g protein in juvenile ovarian granulosa cell tumors: a new prognostic factor?

CONTEXT: Conflicting data have been reported regarding the presence of a constitutive activation of Galphas in ovarian granulosa cell tumors (OGCTs). Although the precise role of this mutation in the transformation of ovarian cells into malignant cells remains debatable, it has been demonstrated in other tissues that the rate of cell proliferation and invasiveness can be influenced by the gsp oncogene. OBJECTIVE: The objective of this study was to determine whether activating mutations of Galphas or Galphai are present in juvenile OGCTs and, if so, whether these mutations are significant prognostic factors. DESIGN AND SETTING: This was a multicentric nationwide study. PATIENTS AND METHODS: Thirty children with juvenile OGCT were included from the malignant germinal tumor protocol of the French Society for Childhood Cancer. Genetic studies of the tumoral DNA used nested PCR, laser microdissection, and direct sequencing. RESULTS: Galphas-activating mutations in hot spot position 201 were found in nine patients (30%). Laser microdissection confirmed that mutations R201C and R201H were exclusively localized in the tumoral granulosa cells and were absent in the ovarian stroma. Patients with a hyperactivated Galphas exhibited a significantly more advanced tumor (P < 0.05) because seven of them (77.7%) were staged as Ic or had had a recurrence. Galphai did not exhibit any mutation. CONCLUSIONS: Activating mutations of Galphas are present in 30% of juvenile OGCTs. The gsp oncogene, which is known to be implicated in cell proliferation and tumoral invasiveness, can be considered as a new prognostic factor of these tumors.

Cell Proliferation↗
PubMed2006

Clinical expression of polycystic ovary syndrome in adolescent girls.

Polycystic ovary syndrome (PCOS) is one of the major causes of adolescent hyperandrogenism and menstrual disorders. Because there is no universal definition for adolescent PCOS, we recommend four out of five criteria: clinical and biologic evidence of hyperandrogenism, hyperinsulinism, oligo-/amenorrhea, and polycystic ovaries on ultrasonography.

Adolescent↗
PubMed2006

Activating mutations of Gsalpha in kidney cancer.

PURPOSE: Heterotrimeric G proteins are signal transduction proteins coupled to hormone receptors that activate intracellular second messenger systems, mainly cyclic adenosine monophosphate mediated protein kinase. Recent studies indicate that G proteins may have a major role in oncogenesis as well as in tumor invasiveness and cell proliferation. The involvement of G proteins was formerly thought to be limited to hormonal signal transduction. Activating Gsalpha mutations have been reported in tumors arising only from highly specialized endocrine tissue, such as pituitary adenomas, toxic thyroid adenomas and differentiated thyroid carcinomas, but never in other nonendocrine tumors. We hypothesized that a constitutive activation of this pathway, that is activated Gsalpha and inhibited Gialpha, could be implicated in kidney cancers. We searched for alterations on the Gsalpha gene GNAS and the Gialpha gene in renal cell carcinoma. MATERIALS AND METHODS: Using nested polymerase chain reaction, enzyme digestions, laser microdissection and direct sequencing we looked for activating mutations on GNAS codons 201 and 227, and inhibiting mutations on the Gialpha gene in 30 consecutive patients with clear cell renal cell carcinoma between January 2003 and January 2004. RESULTS: Somatic (tumor specific) activating mutations of Gsalpha were present in a significant proportion of human clear cell renal cell carcinomas. Activating mutations were identified in 5 of the 30 patient DNA preparations (16.6%) with a substitution of arginine 201 by cysteine in 3 and histidine in 2. CONCLUSIONS: These findings suggest the implication of this pathway in human oncogenesis. It may provide a potential therapeutic approach to these frequent and aggressive tumors.

Adult↗
PubMed2005

Glutamic acid 709 substitutions highlight the importance of the interaction between androgen receptor helices H3 and H12 for androgen and antiandrogen actions.

The mutation of a single amino acid in the ligand binding domain of the human androgen receptor (AR) can induce functional abnormalities; for example, in androgen binding or interactions with coregulators. We report here on the structure/function analysis of the ARE709K substitution that is associated with partial androgen insensitivity syndrome. We introduced several mutations at position 709 and tested the consequences of these changes on AR structure and activity in the presence of androgen and antiandrogens. Our results demonstrate that a strong interaction between helix H12 and residue 709 in H3 is required to obtain a fully functional AR. We show that glutamic acid 709 can be replaced by a bulky tyrosine residue without significant effect on the activation by agonists. In contrast, smaller or linear residues that are unable to maintain a tight interaction with H12 induce a substantial loss of androgen-induced AR activity. We also show that the agonist activity of partial antiandrogens is dependent on the side-chain residue at position 709. Strikingly, the ARE709Y substitution causes the conversion of cyproterone acetate into a pure antiandrogen and bicalutamide into a partial agonist. Together, our structural and functional data reveal the key role of glutamic acid 709 in androgenic and antiandrogenic activities.

Amino Acid Substitution↗
PubMed2005

Increased serum estrogenic bioactivity in three male newborns with ambiguous genitalia: a potential consequence of prenatal exposure to environmental endocrine disruptors.

In the past 15 years, anomalies of male sexual differentiation have greatly increased in both wildlife and humans in different parts of the world. Environmental endocrine disruptors have been implicated in the dramatic rise in neonatal ambiguous genitalia with variable rates of severity, such as micropenis, cryptorchidism, and isolated or associated hypospadias. Because most environmental pollutants, such as organochlorine pesticides, polychlorinated biphenyls, dioxins and furans, alkylphenol polyetholyethoxylates, and phytoestrogens and phtalates, have estrogenic and antiandrogenic activity, they are able to interfere with normal fetal male sexual differentiation. In a neonatal screening program of ambiguous genitalia, we had the opportunity to evaluate three newborns with male pseudohermaphroditism (MPH) whose mothers were exposed to endocrine disruptors during pregnancy. All had normal testosterone production after human chorionic gonadotrophin stimulation testing, suggesting androgen resistance or so-called idiopathic MPH. Sequences of the 5alpha reductase and androgen receptor genes were normal. Since environmental pollutants are known for their estrogenic activity and can be released progressively from the adipose tissue where they accumulate, we detected their presence by measuring the estrogenic bioactivity of the newborns' serum with a recently developed ultrasensitive bioassay. We found higher estrogenic bioactivity in these newborns than in controls. In conclusion, the maternal exposure to environmental pollutants during pregnancy and high estrogenic bioactivity in the newborns' serum highly suggest that ambiguous genitalia are related to fetal exposure to endocrine disruptors.

Agriculture↗
PubMed2005

Association between androgen receptor gene CAG repeat polymorphism and plasma testosterone levels in postmenopausal women.

OBJECTIVES: The biologic action of androgens in target cells depends on plasma androgen levels and receptor transcriptional activity. We investigated the relationship between androgen receptor (AR) CAG repeat polymorphism, serum androgen levels, and anthropometric, metabolic, and hormonal variables in 39 postmenopausal women, taking into consideration the patterns of X-chromosome inactivation. METHODS: Genomic DNA was extracted from peripheral leukocytes. Polymerase chain reactions (PCRs) were performed to amplify the polymorphic (CAG)n repeat of the human AR gene, which were analyzed with GeneScan software (Applied Biosystems, Foster City, CA). The X-chromosome inactivation analysis was based on the AR gene methylation patterns. RESULTS: The mean age of participants was 54.7 years; mean age at menopause was 48 years. The number of CAG repeats ranged from 15 to 30, with a median length of 23. Analysis of X-chromosome inactivation patterns showed 19 cases with a degree of skewing (DS) > or =70% and seven with a DS > or =90%. The X-weighted CAG repeat biallelic mean was significantly lower in individuals with total testosterone (TT) greater than 0.56 ng/mL (group mean) than in the group with TT < or =0.56 (P=.018). No difference was observed between the groups regarding dehydroepiandrosterone sulfate (DHEA-S). Plasma TT was significantly higher in the group with the smaller X-weighted CAG repeat biallelic mean (P=.01). Free androgen index (FAI) was also significantly higher in this group (P=.033). Testosterone levels and FAI were inversely correlated to X-weighted CAG repeat biallelic mean. CONCLUSION: Our data indicate an association between testosterone plasma levels and AR CAG repeats in postmenopausal women, and suggest that plasma levels of androgens in postmenopausal women may be related to variants of the AR gene.

Alleles↗
PubMed2005

5alpha-reductase 2 gene mutations in three unrelated patients of Greek Cypriot origin: identification of an ancestral founder effect.

INTRODUCTION: 5alpha-Steroid reductase deficiency (5alphaSRD) is an autosomal recessive enzymatic deficiency. Mutations in the 5alpha-steroid reductase type 2 gene (SRD5A2) result in male pseudohermaphroditism caused by decreased dihydrotestosterone (DHT) synthesis--a key hormone of virilization of male external genitalia. AIM: To study for the first time patients from the Greek Cypriot population, describe their clinical characteristics, and identify the genetic mutations of the SRD5A2 gene. PATIENTS AND METHODS: Three unrelated patients with 46,XY karyotype born with ambiguous genitalia were examined. Patient 1 was raised as a girl and was diagnosed with partial androgen insensitivity syndrome, based on the clinical picture and incomplete laboratory investigation at the age of 4 years, and underwent gonadectomy. For this patient sequencing analysis of all five exons of the SRD5A2 gene and exons 2 to 8 of the androgen receptor (AR) gene was performed. Patients 2 and 3 were also born with ambiguous genitalia. The hCG test for these two patients was informative of 5alphaSRD, as it showed elevated T/DHT ratio after stimulation. Despite genetic counseling, both families decided to raise their infants as females because of severe under-virilization. Sequencing of the SRD5A2 gene was also completed for both patients. RESULTS: No mutations were found in the AR sequence for patient 1. Patients 1 and 3 were found homozygous for the mutation A/G at splice junction intron 1/exon 2 and patient 2 was found heterozygous for the same A/G substitution and also heterozygous for an additional mutation, Pro181Leu, in exon 3. CONCLUSIONS: The same mutation in the SRD5A2 gene was identified in three unrelated patients, in both homozygous and heterozygous form. This splice mutation was previously reported in Turkish patients. This underlying genetic abnormality may be characteristic for the Eastern Mediterranean region and is likely due to an ancestor effect.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2005

Complete androgen insensitivity syndrome caused by the R855H mutation in the androgen receptor gene.

Complete androgen insensitivity syndrome (CAIS) is characterized by a completely female phenotype in a 46,XY individual and is caused by mutations in the androgen receptor (AR) gene. A 5 year-old girl presented with bilateral hernia and was noted to have bilateral testes. She had a 46,XY karyotype and was diagnosed with CAIS. To identify the underlying mutation, the exons 2 to 8 of the AR gene were amplified by PCR using sets of known primers and reaction conditions. The results of the mutational analysis for the AR showed the presence of the R855H mutation; her mother was found to be heterozygous and both her 46,XX sister and her aunt had a normal AR gene. This mutation, is the result of a guanine to adenine transition in codon 855 at position 2926 in exon 7 of the AR gene, which causes an alteration of the coding nucleotide triad from CGC to CAC, which subsequently causes the substitution from arginine to histidine in the amino acid sequence of the receptor protein molecule. The same mutation has been reported to cause variable phenotypic expression, which could be explained by the presence of additional co-activating factors modifying the biological activity of the AR. The identification of an AR mutation in a girl with CAIS provides important information, because of the syndrome's genetic heterogeneity. This report emphasizes the fact that genetic determinants outside the coding sequence of the AR can influence the function of the AR protein molecule. Phenotypic expression of the mutation may be used for the construction of maps of functional domains of the AR.

Androgen-Insensitivity Syndrome↗
PubMed2004

Childhood obesity.

In March 2004 a group of 65 physicians and other health professionals representing nine countries on four continents convened in Israel to discuss the widespread public health crisis in childhood obesity. Their aim was to explore the available evidence and develop a consensus on the way forward. The process was rigorous, although time and resources did not permit the development of formal evidence-based guidelines. In the months before meeting, participants were allocated to seven groups covering prevalence, causes, risks, prevention, diagnosis, treatment, and psychology. Through electronic communication each group selected the key issues for their area, searched the literature, and developed a draft document. Over the 3-d meeting, these papers were debated and finalized by each group before presenting to the full group for further discussion and agreement. In developing a consensus statement, this international group has presented the evidence, developed recommendations, and provided a platform aimed toward future corrective action and ongoing debate in the international community.

Child↗
PubMed2004

Androgen insensitivity syndrome: somatic mosaicism of the androgen receptor in seven families and consequences for sex assignment and genetic counseling.

Androgen insensitivity syndrome (AIS) is caused by numerous mutations of the androgen receptor (AR) gene. The phenotype may range from partial AIS (PAIS) with ambiguous genitalia to complete AIS (CAIS) with female genitalia. In 70% of the cases, AR mutations are transmitted in an X-linked recessive manner through the carrier mothers, but in 30%, the mutations arise de novo. When de novo mutations occur after the zygotic stage, they result in somatic mosaicisms, which are an important consideration for both virilization in later life-because both mutant and wild-type receptors are expressed-and genetic counseling. We report here six patients with AIS due to somatic mutations of the AR and one mother with somatic mosaicism who transmitted the mutation twice. Of the four patients with PAIS, three presented spontaneous or induced virilization at birth or puberty. These cases underline the crucial role of the remnant wild-type AR for virilization because the same mutations, when they are inherited, lead to CAIS. We also report two novel mutations of the AR, with somatic mosaicism, detected in patients with CAIS. Thus, the remnant wild-type receptor does not always lead to virilization. In one of these patients, a high ratio of wild-type to mutant AR expression was found in the gonads and genital skin fibroblasts. Although no prenatal virilization occurred, the possibility of virilization at puberty could not be excluded, and early gonadectomy was performed. A seventh patient had a CAIS with a novel germline AR mutation. The mutation was inherited from the mother, in whom mosaicism was detected in blood and who transmitted the mutation to a second, XX, offspring. The detection of somatic AR mutations is particularly important for the clinical management and genetic counseling of patients with AIS. Before definite sex assignment, a testosterone treatment trial should be performed in all patients with PAIS, but it becomes crucial when an AR mosaicism has been detected. In patients with CAIS or severe PAIS raised as female, there is no consensus about when (early childhood or puberty) gonadectomy should be performed. When somatic AR mutations are detected, however, gonadectomy should be performed earlier because of the risk of virilization during puberty. When a germline de novo mutation is identified in the index case, the risk of transmission to a second child due to a possible germ cell mosaicism in the mother cannot be excluded. However, given the high number of AR de novo mutations and the rarity of such reports, this risk appears to be very low.

Adolescent↗
PubMed2004

Circulating leptin concentrations can be used as a surrogate marker of fat mass in acute spinal cord injury patients.

To determine the acute effect of neurological lesion on body composition, plasma leptin level, and the lipid profile, 7 male patients with acute and complete spinal cord injury (SCI) and 9 able-bodied (AB) males were investigated. At 16, 24, 36, and 48 weeks after injury, plasma leptin level and the lipid profile were analyzed, while whole body (WB) and regional fat mass (FM) and fat-free soft tissue (FFST) were measured by dual-energy x-ray absorptiometry (DXA). At all stages, despite no difference being found between both groups for body mass index (BMI), SCI patients had higher FM at WB (P < .01), lower (P < .01), and upper limbs (P < .05), while FFST was lower at WB (P < .05) and lower limbs (P < .01). The leptin level increased gradually from week 24 and was higher at weeks 16, 36, and 48 in SCI patients than in AB patients (7.0 +/- 3.9; 9.7 +/- 5.1; 10.6 +/- 5.3, respectively, v 3.5 +/- 2.5 ng. mL(-1)). SCI patients had lower high-density lipoprotein-cholesterol (HDL-C) (P < .05) and apolipoprotein (apo) A1 (P < .01), while no difference was found for total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), or ApoB levels. At all stages, leptin was strongly and positively correlated with WB and regional FM % (r > 0.75; P < .05) and with TC, LDL-C, and ApoB levels (r > 0.65; P < .05). Leptin was negatively correlated with FFST and the ApoA1/ApoB ratio (r > -0.75; P < .05). In conclusion, neurological lesion induced an early and acute alteration in body composition and lipid profile. The strong relationship between serum leptin and FM suggests that this hormone can be used as a surrogate marker of FM in acute SCI patients and thus would serve as a good indicator for cardiovascular disease risk.

Absorptiometry, Photon↗