Shifting the landscape: Dominant C-terminal rare missense FOXL2 variants in non-syndromic primary ovarian failure etiology.

Pathogenic germline variants in the FOXL2 gene are associated with Blepharophimosis, Ptosis, and Epicanthus Inversus syndrome (BPES) in humans, an autosomal dominant condition. Two forms of BPES have emerged: (i) type I (BPES-I), characterized by ocular signs and primary ovarian failure (POI), and (ii) type II (BPES-II) with no systemic associations. This study aimed to compare the distribution of FOXL2 variants in idiopathic POI/DOR (diminished ovarian reserve) and both types of BPES, and to determine the involvement of FOXL2 in non-syndromic forms of POI/DOR. We studied the whole coding region of the FOXL2 gene using next-generation sequencing in 1282 patients with non-syndromic POI/DOR. Each identified FOXL2 variant was compared to its frequency in the general population, considering ethnicity. Screening of the entire coding region of the FOXL2 gene allowed us to identify 10 different variants, including nine missense variants. Of the patients with POI/DOR, 14 (1%) carried a FOXL2 variant. Significantly, six out of nine missense variants (67%) were overrepresented in our POI/DOR cohort compared to the general or specific ethnic subgroups. Our findings strongly suggest that five rare missense variants, mainly located in the C-terminal region of FOXL2 are high-risk factors for non-syndromic POI/DOR, though FOXL2 gene implication accounts for approximately 0.54% of non-syndromic POI/DOR cases. These results support the implementation of routine genetic screening for patients with POI/DOR in clinical settings.

Biallelic FANCA variants detected in sisters with isolated premature ovarian insufficiency.

Premature ovarian insufficiency is a common form of female infertility affecting up to 4% of women and characterised by amenorrhea with elevated gonadotropin before the age of 40. Oocytes require controlled DNA breakage and repair for homologous recombination and the maintenance of oocyte integrity. Biallelic disruption of the DNA damage repair gene, Fanconi anemia complementation group A (FANCA), is a common cause of Fanconi anaemia, a syndrome characterised by bone marrow failure, cancer predisposition, physical anomalies and POI. There is ongoing dispute about the role of heterozygous FANCA variants in POI pathogenesis, with insufficient evidence supporting causation. Here, we have identified biallelic FANCA variants in French sisters presenting with POI, including a novel missense variant of uncertain significance and a likely pathogenic deletion that initially evaded detection. Functional studies indicated no discernible effect on DNA damage sensitivity in patient lymphoblasts. These novel FANCA variants add evidence that heterozygous loss of one allele is insufficient to cause DNA damage sensitivity and POI. We propose that intragenic deletions, that are relatively common in FANCA, may be missed without careful analysis, and could explain the presumed causation of heterozygous variants. Accurate variant curation is critical to optimise patient care and outcomes.

Stratification of the risk of ovarian dysfunction by studying the complexity of intermediate and premutation alleles of the FMR1 gene.

FMR1 premutation female carriers are at risk of developing premature/primary ovarian insufficiency (POI) with an incomplete penetrance. In this study, we determined the CGG repeat size among 1095 women with diminished ovarian reserve (DOR) / POI and characterized the CGG/AGG substructure in 44 women carrying an abnormal FMR1 repeat expansion number, compared to a group of 25 pregnant women carrying an abnormal FMR1 CGG repeat size. Allelic complexity scores of the FMR1 gene were calculated and compared between the two groups. In the DOR/POI cohort, 2.1% of women presented with an intermediate repeat size and 1.9% with a premutation. Our results suggest that the risk of POI is highest in the mid-range of CGG repeats. We observed that the allelic score is significantly higher in POI women compared to the pregnant women group (p-value = 0.02). We suggest that a high allelic score due to more than 2 AGG interspersions in the context of an intermediate number of repetitions could favor POI. Larger studies are still needed to evaluate the relevance of this new tool for the determination of the individual risk of developing POI in women with abnormal number of CGG repeats.

NOBOX gene variants in premature ovarian insufficiency: ethnicity-dependent insights.

PURPOSE: Premature ovarian insufficiency (POI) affects approximately 1% of women before the age of 40. Genetic contribution is a significant component of POI. The NOBOX gene was considered one of the major genetic causes of POI. However, the pathogenicity and the penetrance of NOBOX variants remain unclear. METHODS: We studied the whole coding region of the NOBOX gene by next generation sequencing in a cohort of 810 patients with POI, and we compared the frequency of each identified NOBOX variant to the general population taking into account the ethnicity of each individual. RESULTS: Screening of the whole coding region of the NOBOX gene allowed us to identify 35 different variants, including 5 loss-of-function variants. In total, 171 patients with POI (25%) carried out at least one NOBOX variant. Regarding missense variants, we observed a significant overrepresentation of the most frequent ones in our 810 POI patients as compared to the general, except for p.(Arg117Trp). However, taking into account the ethnic origin of the individuals, we observed no significant OR difference for p.(Arg44Leu) and p.(Arg117Trp) in African subgroup and for p.(Asp452Asn) in European subgroup. CONCLUSION: This population study suggests that the p.(Arg44Leu) variant could be considered benign variant and that the p.(Asp452Asn) and p.(Arg117Trp) variants could be considered moderate risk pathogenic variants with probably partial and very low penetrance and/or expressivity. In contrast, p.(Gly91Trp) and p.(Gly152Arg) variants could be considered pathogenic variants with a moderate functional impact.

Fertility and pregnancy outcomes in women with nonclassic 21-hydroxylase deficiency.

INTRODUCTION: Overall fertility and pregnancy outcomes in patients with nonclassic congenital adrenal hyperplasia (NCCAH) have been poorly studied. It has been suggested that hydrocortisone (HC) may decrease the time to conceive (TTC) and the rate of miscarriage in these patients. OBJECTIVES: To describe fertility and pregnancy outcomes in a large cohort of NCCAH women. The secondary objective was to identify factors that could impact reproductive outcomes, with a particular focus on HC dose and genetic status. DESIGN: Retrospective study in a referral center for congenital adrenal hyperplasia. PATIENTS AND MEASUREMENTS: One hundred seventy-three female patients with NCCAH confirmed by genetic testing, followed in our center between 2010 and 2019. RESULTS: Among the 173 patients, 95 women had a parental project, 86 of whom presented 176 pregnancies, 56% under glucocorticoid (GC) treatment and 44% without, and 76 women obtained 128 live births. Two-thirds of the patients regularized their cycle under GC treatment, with significant decrease of androgens and progesterone levels. This treatment was associated with a shortening of TTC (coef ß = -.196, information coefficient [IC] = [-10.7; -0.91], p = .021). Androgen levels and TTC were positively correlated to the rate of miscarriage (OR = 4.8, IC = [1.15; 20.34], p = .021 for testosterone, OR = 1.4, IC = [1.05; 1.81], p = .02 for androstenedione, and OR = 1.03, IC = [1.01; 1.06], p = .015 for TTC). There was no difference in terms of obstetric outcomes between patients with or without GC treatment. CYP21A2 genotype had no impact on pregnancy outcome or TTC. CONCLUSIONS: Infertility is relative in patients with NCCAH. HC seems beneficial for fertility and pregnancy outcomes, especially for patients with menstrual disorders and high preconceptional androgen levels.

Dominant TP63 missense variants lead to constitutive activation and premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is a leading form of female infertility, characterised by menstrual disturbance and elevated follicle-stimulating hormone before age 40. It is highly heterogeneous with variants in over 80 genes potentially causative, but the majority of cases having no known cause. One gene implicated in POI pathology is TP63. TP63 encodes multiple p63 isoforms, one of which has been shown to have a role in the surveillance of genetic quality in oocytes. TP63 C-terminal truncation variants and N-terminal duplication have been described in association with POI, however, functional validation has been lacking. Here we identify three novel TP63 missense variants in women with nonsyndromic POI, including one in the N-terminal activation domain, one in the C-terminal inhibition domain, and one affecting a unique and poorly understood p63 isoform, TA*p63. Via blue-native page and luciferase reporter assays we demonstrate that two of these variants disrupt p63 dimerization, leading to constitutively active p63 tetramer that significantly increases the transcription of downstream targets. This is the first evidence that TP63 missense variants can cause isolated POI and provides mechanistic insight that TP63 variants cause POI due to constitutive p63 activation and accelerated oocyte loss in the absence of DNA damage.

A recessive variant in TFAM causes mtDNA depletion associated with primary ovarian insufficiency, seizures, intellectual disability and hearing loss.

Mitochondrial disorders are collectively common, genetically heterogeneous disorders in both pediatric and adult populations. They are caused by molecular defects in oxidative phosphorylation, failure of essential bioenergetic supply to mitochondria, and apoptosis. Here, we present three affected individuals from a consanguineous family of Pakistani origin with variable seizures and intellectual disability. Both females display primary ovarian insufficiency (POI), while the male shows abnormal sex hormone levels. We performed whole exome sequencing and identified a recessive missense variant c.694C > T, p.Arg232Cys in TFAM that segregates with disease. TFAM (mitochondrial transcription factor A) is a component of the mitochondrial replisome machinery that maintains mtDNA transcription and replication. In primary dermal fibroblasts, we show depletion of mtDNA and significantly altered mitochondrial function and morphology. Moreover, we observed reduced nucleoid numbers with significant changes in nucleoid size or shape in fibroblasts from an affected individual compared to controls. We also investigated the effect of tfam impairment in zebrafish; homozygous tfam mutants carrying an in-frame c.141_149 deletion recapitulate the mtDNA depletion and ovarian dysgenesis phenotypes observed in affected humans. Together, our genetic and functional data confirm that TFAM plays a pivotal role in gonad development and expands the repertoire of mitochondrial disease phenotypes.

GGPS1 Mutations Cause Muscular Dystrophy/Hearing Loss/Ovarian Insufficiency Syndrome.

OBJECTIVE: A hitherto undescribed phenotype of early onset muscular dystrophy associated with sensorineural hearing loss and primary ovarian insufficiency was initially identified in 2 siblings and in subsequent patients with a similar constellation of findings. The goal of this study was to understand the genetic and molecular etiology of this condition. METHODS: We applied whole exome sequencing (WES) superimposed on shared haplotype regions to identify the initial biallelic variants in GGPS1 followed by GGPS1 Sanger sequencing or WES in 5 additional families with the same phenotype. Molecular modeling, biochemical analysis, laser membrane injury assay, and the generation of a Y259C knock-in mouse were done. RESULTS: A total of 11 patients in 6 families carrying 5 different biallelic pathogenic variants in specific domains of GGPS1 were identified. GGPS1 encodes geranylgeranyl diphosphate synthase in the mevalonate/isoprenoid pathway, which catalyzes the synthesis of geranylgeranyl pyrophosphate, the lipid precursor of geranylgeranylated proteins including small guanosine triphosphatases. In addition to proximal weakness, all but one patient presented with congenital sensorineural hearing loss, and all postpubertal females had primary ovarian insufficiency. Muscle histology was dystrophic, with ultrastructural evidence of autophagic material and large mitochondria in the most severe cases. There was delayed membrane healing after laser injury in patient-derived myogenic cells, and a knock-in mouse of one of the mutations (Y259C) resulted in prenatal lethality. INTERPRETATION: The identification of specific GGPS1 mutations defines the cause of a unique form of muscular dystrophy with hearing loss and ovarian insufficiency and points to a novel pathway for this clinical constellation. ANN NEUROL 2020;88:332-347.

Genomic sequencing highlights the diverse molecular causes of Perrault syndrome: a peroxisomal disorder (PEX6), metabolic disorders (CLPP, GGPS1), and mtDNA maintenance/translation disorders (LARS2, TFAM).

Perrault syndrome is a rare heterogeneous condition characterised by sensorineural hearing loss and premature ovarian insufficiency. Additional neuromuscular pathology is observed in some patients. There are six genes in which variants are known to cause Perrault syndrome; however, these explain only a minority of cases. We investigated the genetic cause of Perrault syndrome in seven affected individuals from five different families, successfully identifying the cause in four patients. This included previously reported and novel causative variants in known Perrault syndrome genes, CLPP and LARS2, involved in mitochondrial proteolysis and mitochondrial translation, respectively. For the first time, we show that pathogenic variants in PEX6 can present clinically as Perrault syndrome. PEX6 encodes a peroxisomal biogenesis factor, and we demonstrate evidence of peroxisomal dysfunction in patient serum. This study consolidates the clinical overlap between Perrault syndrome and peroxisomal disorders, and highlights the need to consider ovarian function in individuals with atypical/mild peroxisomal disorders. The remaining patients had variants in candidate genes such as TFAM, involved in mtDNA transcription, replication, and packaging, and GGPS1 involved in mevalonate/coenzyme Q10 biosynthesis and whose enzymatic product is required for mouse folliculogenesis. This genomic study highlights the diverse molecular landscape of this poorly understood syndrome.

TP63-truncating variants cause isolated premature ovarian insufficiency.

Premature ovarian insufficiency involves amenorrhea and elevated follicle-stimulating hormone before age 40, and its genetic basis is poorly understood. Here, we study 13 premature ovarian insufficiency (POI) patients using whole-exome sequencing. We identify PREPL and TP63 causative variants, and variants in other potentially novel POI genes. PREPL deficiency is a known cause of syndromic POI, matching the patients' phenotype. A role for TP63 in ovarian biology has previously been proposed but variants have been described in multiorgan syndromes, and not isolated POI. One patient with isolated POI harbored a de novo nonsense TP63 variant in the terminal exon and an unrelated patient had a different nonsense variant in the same exon. These variants interfere with the repression domain while leaving the activation domain intact. We expand the phenotypic spectrum of TP63-related disorders, provide a new genotype:phenotype correlation for TP63 and identify a new genetic cause of isolated POI.

Gene variants identified by whole-exome sequencing in 33 French women with premature ovarian insufficiency.

PURPOSE: To investigate the potential genetic etiology of premature ovarian insufficiency (POI). METHODS: Whole-exome sequencing (WES) was done on DNA samples from women diagnosed with POI. Mutations identified were analyzed by in silico tools and were annotated according to the guidelines of the American College of Medical Genetics and Genomics. Plausible variants were confirmed by Sanger sequencing. RESULTS: Four of the 33 individuals (12%) carried pathogenic or likely pathogenic variants, and 6 individuals carried variants of unknown significance. The genes identified with pathogenic or likely pathogenic variants included PMM2, MCM9, and PSMC3IP. CONCLUSIONS: WES is an efficient tool for identifying gene variants in POI women; however, interpretation of variants is hampered by few exome studies involving ovarian disorders and the need for trio sequencing to determine inheritance and to detect de novo variants.

Surgery is not superior to dilation for the management of vaginal agenesis in Mayer-Rokitansky-Küster-Hauser syndrome: a multicenter comparative observational study in 131 patients.

BACKGROUND: Vaginal agenesis in Mayer-Rokitansky-Küster-Hauser syndrome can be managed either by various surgeries or dilation. The choice still depends on surgeon's preferences rather than on quality comparative studies and validated protocols. OBJECTIVE: We sought to compare dilation and surgical management of vaginal agenesis in Mayer-Rokitansky-Küster-Hauser syndrome, in terms of quality of life, anatomical results, and complications in a large multicenter population. STUDY DESIGN: Our multicenter study included 131 patients >18 years, at least 1 year after completing vaginal agenesis management. All had an independent gynecological evaluation including a standardized pelvic exam, and completed the World Health Organization Quality of Life instrument (general quality of life) as well as the Female Sexual Function Index and Female Sexual Distress Scale-Revised (sexual quality of life) scales. Groups were: surgery (N = 84), dilation therapy (N = 26), and intercourse (N = 20). One patient was secondarily excluded because of incomplete surgical data. For statistics, data were compared using analysis of variance, Student, Kruskal-Wallis, Wilcoxon, and Student exact test. RESULTS: Mean age was 26.5 ± 5.5 years at inclusion. In all groups, World Health Organization Quality of Life scores were not different between patients and the general population except for lower psychosocial health and social relationship scores (which were not different between groups). Global Female Sexual Function Index scores were significantly lower in the surgery and dilation therapy groups (median 26 range [2.8-34.8] and 24.7 [2.6-34.4], respectively) than the intercourse group (30.2 [7.8-34.8], P = .044), which had a higher score only in the satisfaction dimension (P = .004). However, the scores in the other dimensions of Female Sexual Function Index were not different between groups. The Female Sexual Distress Scale-Revised median scores were, respectively, 17 [0-52], 20 [0-47], and 10 [10-40] in the surgery, dilation therapy, and intercourse groups (P = .38), with sexual distress in 71% of patients. Median vaginal depth was shorter in dilatation therapy group (9.6 cm [5.5-12]) compared to surgery group (11 cm [6-15]) and intercourse group (11 cm [6-12.5]) (P = .039), but remained within normal ranges. One bias in the surgery group was the high number of sigmoid vaginoplasties (57/84, 68%), but no differences were observed between surgeries. Only 4 patients achieved vaginas <6.5 cm. Delay between management and first intercourse was 6 months (not significant). Seventy patients (53%) had dyspareunia (not significant), and 17 patients all from the surgery group had an abnormal pelvic exam. In the surgery group, 34 patients (40.5%) had complications, requiring 20 secondary surgeries in 17 patients, and 35 (42%) needed postoperative dilation. In the dilation therapy group, 13 (50%) needed maintenance dilation. CONCLUSION: Surgery is not superior to therapeutic or intercourse dilation, bears complications, and should therefore be only a second-line treatment. Psychological counseling is mandatory at diagnosis and during therapeutic management.

Long-term outcome of ovarian function in women with intermittent premature ovarian insufficiency.

CONTEXT: Spontaneous resumption of ovarian function is not a rare phenomenon in patients with premature ovarian insufficiency (POI). The outcome of this resumption is not known. OBJECTIVE: To describe the outcome following the resumption of ovarian function in POI patients. DESIGN: Cross-sectional study. SETTING: University medical centre. PATIENTS AND MAIN OUTCOME MEASURES: Cumulative incidence of ovarian function resumption and risk factors arresting this resumption during follow-up were determined in a large cohort of POI women. RESULTS: Five hundred and seven patients were included in the study, with a follow-up of 3·44 ± 4·05 years (0-29). Of these, 117 (23%) had features of ovarian function resumption. The cumulative incidence of pregnancy was 3·5% among the whole cohort and 15·3% among patients with resumption of ovarian function. Fifty-five patients (47%) experienced an arrest of their resumption during the follow-up period. In univariate analysis, high FSH and DHEA levels at initial evaluation were risk factors for the arrest of the resumption of ovarian function. In multivariate analysis, high FSH levels at the initial evaluation [1·89 (1·10-3·23), P = 0·03] and older age at diagnosis [1·53 (1·01-2·33), P = 0·04] were risk factors for the arrest of this resumption. CONCLUSION: Resumption of ovarian function is not a rare or brief phenomenon in POI women. The identification of predictive factors of this resumption, as well as its duration, increases our knowledge of the natural history of POI, and will improve the medical management, especially infertility counselling of these patients.

Prevalence of and Risk Factors for Anal Oncogenic Human Papillomavirus Infection Among HIV-Infected Women in France in the Combination Antiretroviral Therapy Era.

BACKGROUND: Little is known about the type-specific prevalence of anal human papillomavirus (HPV) infection and risk factors for anal high-risk (HR) HPV infection in human immunodeficiency virus (HIV)-infected women. METHODS: A cross-sectional study of anal and cervical HPV infection was nested within a gynecological cohort of HIV-infected women. Specimens were tested for type-specific DNA using a polymerase chain reaction-based assay. RESULTS: The study population consisted of 311 women with a median age of 45.3 years, of whom 42.8% originated from sub-Saharan Africa and 96.8% were receiving combination antiretroviral therapy. The median CD4(+)cell count was 612/µL, and the HIV load was <50 copies/mL in 84.1%. HR-HPV types were detected in the anal canal in 148 women (47.6%) and in the cervix in 82 (26.4%). HPV-16 was the most prevalent type in both the anal canal (13.2% of women) and the cervix (5.1%). In multivariable analysis, factors associated with prevalent anal HR-HPV infection were CD4(+)count <350/µL (odds ratio, 2.9; 95% confidence interval, 1.3-6.5), concurrent cervical lesions (2.6; 1.0-4.3), and cervical HR-HPV infection (1.8; 1.0-3.2). CONCLUSIONS: The high prevalence of HR-HPV types, including HPV-16, in the anal canal of HIV-positive women is concerning. Anal cancer screening should be considered for HIV-positive women as part of their routine care.

An Application of NGS for Molecular Investigations in Perrault Syndrome: Study of 14 Families and Review of the Literature.

Perrault syndrome (PS) is a rare autosomal recessive condition characterized by deafness and gonadic dysgenesis. Recently, mutations in five genes have been identified: C10orf2, CLPP, HARS2, HSD17B4, and LARS2. Probands included are presented with sensorineural deafness associated with gonadic dysgenesis. DNA was sequenced using next-generation sequencing (NGS) with a panel of 35 deafness genes including the five Perrault genes. Exonic variations known as pathogenic mutations or detected with <1% frequency in public databases were extracted and subjected to segregation analysis within each family. Both mutations and low coverage regions were analyzed by Sanger sequencing. Fourteen female index patients were included. The screening in four cases has been extended to four family members presenting with PS phenotype. For four unrelated patients (28.6%), causative mutations were identified: three homozygous mutations in C10orf2, CLPP, and HARS2, and one compound heterozygous mutation in LARS2. Three additional heterozygous mutations in LARS2 and HSD17B4 were found in three independent familial cases. All these missense mutations were verified by Sanger sequencing. Familial segregation analyses confirmed the molecular diagnosis in all cases carrying biallelic mutations. Because of NGS, molecular analysis confirmed the clinical diagnosis of PS in 28.6% of our cohort and four novel mutations were found in four Perrault genes. For the unsolved cases, exome sequencing should be performed to search for a sixth unknown PS gene.

Spontaneous fertility and pregnancy outcomes amongst 480 women with Turner syndrome.

STUDY QUESTION: What are the prevalence and the outcomes of spontaneous pregnancies (SP) in a large cohort of French women with Turner syndrome (TS)? SUMMARY ANSWER: Amongst 480 women with TS, 27 women (5.6%) had a total of 52 SP, with 30 full-term deliveries for 18 women. WHAT IS KNOWN ALREADY: Primary ovarian insufficiency is a classic feature of TS. So far, few studies have evaluated the rate of SP in these patients. STUDY DESIGN, SIZE, DURATION: The French Ministry of Health set up a National Reference Centre for Rare Growth Disorders (CRMERC), including TS. We studied a cohort of adult TS patients from seven endocrine units (Saint-Antoine, Pitié-Salpêtrière, Bicêtre, Lyon, Marseille, Brest, Reims Hospitals) belonging to this centre, between January 1999 and January 2014. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 480 adult patients with TS were included. The patients' clinical characteristics, karyotypes and reproductive histories had been collected, after informed consent, in a web database called CEMARA. Our reference population was issued from a database belonging to the French Health Ministry, collecting pregnancy outcomes in the French general population. In order to find predictive characteristics of SP, TS with spontaneous pregnancies were compared with non-pregnant TS patients from our cohort. MAIN RESULTS AND THE ROLE OF CHANCE: There were 27 patients (5.6%) who had a total of 52 SP. The two predictive factors which correlated with occurrence of a SP were spontaneous menarche and mosaic karyotype. The median delay to conception was 6 months (range 0-84). Miscarriage occurred in 16 pregnancies, 30.8% versus 15% in the general French population (P < 0.01). The remaining pregnancy outcomes were legal abortion (n = 2), medical interruption (n = 3), intrauterine fetal death (n = 1) and delivery at term (n = 30). Caesarean section rates were higher than in the general population, respectively 46.7% versus 21% (P < 0.001). Pregnancy-induced hypertensive disorders (PHDs) occurred in four cases (13.3%), including two cases of mild pre-eclampsia (6.7%). Neither aortic root dilatation nor aortic dissection were observed. The median birthweight was 3030 g (range 2020-3460). Two cases of TS were identified in the 17 daughters issued from this cohort. LIMITATIONS, REASONS FOR CAUTION: It would have been interesting to evaluate AMH levels and SP occurrence, as a predictive factor. Unfortunately, hormonal measurements were missing for some patients. Prospective studies are necessary to display prognostic values of AMH for SP and thus better target fertility preservation programmes in TS patients. WIDER IMPLICATIONS OF THE FINDINGS: This study suggests that pregnancy outcomes in SPs are more favourable than those after oocyte donation in TS patients. However, the risk of fetal chromosomal abnormalities remains high. Our study will be useful in order to give patients with TS, their families, paediatricians and physicians involved in reproduction, better counselling concerning their fertility. STUDY FUNDING/COMPETING INTERESTS: Funding was provided by the Association pour la recherche Claude Bernard, Paris France All authors claim no competing interests. TRIAL REGISTRATION NUMBER: NA.