Aurore Bouty

Disorders of sex development: Insights from targeted gene sequencing of a large international patient cohort

BackgroundDisorders of sex development (DSD) are congenital conditions in which chromosomal, gonadal, or phenotypic sex is atypical. Clinical management of DSD is often difficult and currently only 13% of patients receive an accurate clinical genetic diagnosis. To address this we have developed a massively parallel sequencing targeted DSD gene panel which allows us to sequence all 64 known diagnostic DSD genes and candidate genes simultaneously.ResultsWe analyzed DNA from the largest reported international cohort of patients with DSD (278 patients with 46,XY DSD and 48 with 46,XX DSD). Our targeted gene panel compares favorably with other sequencing platforms. We found a total of 28 diagnostic genes that are implicated in DSD, highlighting the genetic spectrum of this disorder. Sequencing revealed 93 previously unreported DSD gene variants. Overall, we identified a likely genetic diagnosis in 43% of patients with 46,XY DSD. In patients with 46,XY disorders of androgen synthesis and action the genetic diagnosis rate reached 60%. Surprisingly, little difference in diagnostic rate was observed between singletons and trios. In many cases our findings are informative as to the likely cause of the DSD, which will facilitate clinical management.ConclusionsOur massively parallel sequencing targeted DSD gene panel represents an economical means of improving the genetic diagnostic capability for patients affected by DSD. Implementation of this panel in a large cohort of patients has expanded our understanding of the underlying genetic etiology of DSD. The inclusion of research candidate genes also provides an invaluable resource for future identification of novel genes.

The Genetic and Environmental Factors Underlying Hypospadias

Hypospadias results from a failure of urethral closure in the male phallus and affects 1 in 200-300 boys. It is thought to be due to a combination of genetic and environmental factors. The development of the penis progresses in 2 stages: an initial hormone-independent phase and a secondary hormone-dependent phase. Here, we review the molecular pathways that contribute to each of these stages, drawing on studies from both human and mouse models. Hypospadias can occur when normal development of the phallus is disrupted, and we provide evidence that mutations in genes underlying this developmental process are causative. Finally, we discuss the environmental factors that may contribute to hypospadias and their potential immediate and transgenerational epigenetic impacts.

DICER1 pleuropulmonary blastoma familial tumour predisposition syndrome: What the paediatric urologist needs to know

INTRODUCTION Germline-inactivating DICER1 mutations are responsible of a familial tumour susceptibility syndrome with an increased risk of tumours, mainly pleuropulmonary blastoma (PPB). DICER1 mutations also cause a range of other tumours, some of them in urogenital organs (cystic nephroma [CN], ovarian sex cord-stromal tumours, bladder and cervix embryonal rhabdomyosarcoma [ERMS]). OBJECTIVE The aim was to clarify the range of urogenital phenotypes associated with DICER1 mutations and to give practical course of action to paediatric urologist that are exposed to DICER1-related conditions. STUDY DESIGN A literature review was performed. Pertinent papers focused on urogenital diseases associated with DICER1 mutations were reviewed. RESULTS Seventy per cent of CN have a DICER1 germline mutation. The majority of them (80%) have PPB. Like PPB, CN could undergo a malignant progression to a primitive sarcoma. Some rare cases of Wilms tumours were reported. Regarding gonadal manifestations, sex-cord stromal neoplasia of the ovary, especially Sertoli-Leydig cell tumour (SLCT), is the most frequent tumour associated with DICER1 germline mutation. Germline DICER1 mutations also predispose to uterine cervix and bladder ERMS. DISCUSSION The presence of unusual tumours suggesting DICER1 mutations may alert clinicians. The first step is to obtain a complete familial history. The variable clinical presentation and the modest penetrance raise concerns about the appropriateness of genetic testing to patients and their relatives. The education of DICER1 mutations carriers about tumour-related symptoms is consensual. In the first 5 years of life, a yearly chest X-ray and abdominal ultrasound are recommended. CONCLUSION The presence of a CN, ovarian SLCT or urogenital ERMS in a child should alert the clinician to the possibility of DICER1 mutation and the associated risk of PPB. Individuals with one of the typical DICER1 conditions should be offered DICER1 analysis. Despite the low penetrance, a genetic counselling and testing should be offered to the family of the affected child.

Testicular biopsy in prepubertal boys: a worthwhile minor surgical procedure?

No consensus exists regarding the precise role of testicular biopsy in prepubertal boys, although it is considered useful for assessing the potential consequences of undescended testes on fertility. Current scientific knowledge indicates that surgeons should broaden indications for this procedure. For example, the use of immunohistochemical markers such as OCT/3-4, TSPY, Kit ligand (SCF) and ALPP (PLAP) has considerably facilitated the detection of germ cell tumour precursors, such as carcinoma in situ and/or gonadoblastoma. These markers are very important for evaluating malignancy risk in undervirilized patients with 46,XY disorders of sexual development. Testicular histology is also of considerable value in the prediction of both fertility potential and risk of cancer in individuals with undescended testes, particularly those with intraabdominal undescended testes. New possibilities for the preservation of fertility after gonadotoxic chemotherapy — even for prepubertal boys — are emerging. Cryopreservation of testicular tissue samples for the preservation of fertility — although still an experimental method at present — is appealing in this context. In our opinion, testicular biopsy in prepubertal boys is a minor procedure that can provide valuable information for predicting the risk of malignancy and fertility, and might be useful in fertility preservation in the near future.

Bladder continent catheterizable conduit (the Mitrofanoff procedure): Long-term issues that should not be underestimated

BACKGROUND Effective bladder emptying by clean intermittent catheterization for children with severe bladder dysfunction is critical for renal preservation and social integration. Use of a continent catheterizable conduit (CCC) as urethral alternative procedure provides effective bladder drainage. However, it brings a substantive maintenance. METHODS Retrospective review of the indications and long-term outcomes of 54 patients with a Mitrofanoff procedure in a single center over a 20-year period (1995-2015). RESULTS Indications of CCC include 21 neurogenic bladders, 12 patients with epispadias/exstrophy, 13 bladder outlet obstruction, 6 malignancies and 2 cloaca. Median age at surgery was 8.3years (4months-20years). The appendix was used in 76% of cases. Most frequently encountered complication was stomal stenosis (n=17/34, 50%), occurring at median time of 9months (2months-13years). The other complications were: leakage in 9 (26.5%); conduit stricture in 5 (14.7%), angulation of the conduit in 2 (5.8%) and prolapse in one (3%). Operative revision was encountered by 33 (61%) patients, the majority in the first 2years. Median follow-up was 4.3years (3months-16years). CONCLUSIONS CCC has a high incidence of complication. It has to be used only when the native urethra is not suitable for catheterization. Carers, patients and families must be prepared to deal with both the complexity of index conditions and the complications of this procedure.

Disorders of sex development

Disorders of sex development (DSD) are rare, complex anomalies of genital development that often present with an ambiguous genital appearance at birth. Rapid recognition and diagnosis are essential to prevent inappropriate gender assignment in the neonatal ward. After morphological and molecular assessment is complete a management plan is developed by a multidisciplinary team in the tertiary and/or quaternary referral centre.

Variants in congenital hypogonadotrophic hypogonadism genes identified in an Indonesian cohort of 46,XY under-virilised boys

BackgroundCongenital hypogonadotrophic hypogonadism (CHH) and Kallmann syndrome (KS) are caused by disruption to the hypothalamic-pituitary-gonadal (H-P-G) axis. In particular, reduced production, secretion or action of gonadotrophin-releasing hormone (GnRH) is often responsible. Various genes, many of which play a role in the development and function of the GnRH neurons, have been implicated in these disorders. Clinically, CHH and KS are heterogeneous; however, in 46,XY patients, they can be characterised by under-virilisation phenotypes such as cryptorchidism and micropenis or delayed puberty. In rare cases, hypospadias may also be present.ResultsHere, we describe genetic mutational analysis of CHH genes in Indonesian 46,XY disorder of sex development patients with under-virilisation. We present 11 male patients with varying degrees of under-virilisation who have rare variants in known CHH genes. Interestingly, many of these patients had hypospadias.ConclusionsWe postulate that variants in CHH genes, in particular PROKR2, PROK2, WDR11 and FGFR1 with CHD7, may contribute to under-virilisation phenotypes including hypospadias in Indonesia.

Urethral duplication in girls: Three cases associating an accessory epispadiac urethra and a main hypospadiac urethra

INTRODUCTION Urethral duplication is extremely rare in girls, with less than 40 cases reported so far. Most of them present as a prepubic sinus. Literature is scare regarding aetiology, classification and management in other forms. This study presents three cases of sagittal urethral duplication in girls presenting a main hypospadiac urethra and an accessory epispadiac urethra. PATIENTS AND METHODS Medical records were retrospectively reviewed of three girls with urethral duplication managed over a 30-year period at a single institution. Circumstances of diagnosis, management and outcomes were analysed. RESULTS The oldest case presented as a neonatal retrovesical mass with an accessory clitoral stream, whereas the two more recent cases presented with antenatal hydrocolpos and bilateral ureterohydronephrosis. Cases 1 and 3 had an incomplete duplication, while Case 2 had a complete form. In Case 3, the duplication was associated with a urogenital sinus and an anteriorly placed anus. Management involved resection of the epispadiac accessory urethra to achieve continence, with dilatation and/or mobilisation of the hypospadiac one. All girls are now aged >5 years old and are continent, and one is old enough to have normal menstruation. Renal function is normal in all. The summary table presents the schematic anatomical description as shown on micturating cystourethrogram and endoscopy, as well as the management for each patient. DISCUSSION Step-by-step management is necessary in urethral duplication. The neonatal emergency is to release the urinary tract compression by evacuating urinary retention or hydrocolpos. Later in infancy, decision has to be taken regarding the urethras. If the resection of the epispadiac accessory urethra seems acceptable to achieve continence, the attitude towards the hypospadiac channel is more controversial and should be individualised. Embryologic and aetiopathogenic pathways are still missing to uniformly characterise the malformation. CONCLUSION Paediatric urologists should remember that there is a wide spectrum of urethral duplication in girls, and that various presentations exist beside the more classic prepubic sinus.

Is peritoneal dialysis feasible after laparotomy in children? A case-control series to compare outcomes

OBJECTIVES Peritoneal dialysis (PD) is the modality of choice for children with end-stage renal disease (ESRD) awaiting renal transplant; however, this option is sometimes avoided for those with previous laparotomy. The goal of this study was to compare the outcomes of PD in patients with and without previous laparotomy. PATIENTS AND METHODS Twenty-four patients who had been started on peritoneal dialysis were retrospectively analysed. Group LAP consisted of six patients with previous laparotomy, and Group NO-LAP of 18 controls with either retroperitoneal or no abdominal surgery. The percentage of theoretical maximum volume of infusion, time to reach it, complications (infection and drainage difficulties), and number of catheters needed to finish therapy were analysed. RESULTS The characteristics of patients and technique of insertion are presented in Table. The percentage of maximum theoretical volume of infusion was similar in both groups. Median of catheter survival was similar in both groups. Complications were divided into malfunction (slow drainage, obstruction or leak) and infection. Incidence of complications per catheter and per month of dialysis was ten times lower in Group NO-LAP. Peritoneal dialysis failed in one patient with recurrent intraperitoneal adhesions after adhesiolysis in Group LAP. CONCLUSION Despite a higher incidence of complications (malfunction and infections), PD remains an acceptable option after laparotomy. In this series, it was sufficient in achieving adequate filtration in five patients.

A Move to Conservativism in Pediatric Urology

Purpose of ReviewTo define the evidence on the move to conservative treatment in four areas of pediatric urology: laparoscopic ureteric clipping in non-functioning duplex kidney, management of multicystic dysplastic kidney (MCDK), intravesical botulinum toxin injection in detrusor over activity, and risk stratification of gonadal tumors in disorders of sexual development.Recent FindingsLaparoscopic ureteric clipping has been validated in one preliminary study. Lesser investigation and non-operative management of MCDK has been validated. An increasing body of evidence showing botulinum toxin injection can effectively treat detrusor over activity and reduce the need for bladder augmentation. New data on testicular biopsy can now identify patients at risk of germ cell tumor and reduce need for gonadectomy.SummaryPediatric urology is shifting to less invasive management in a number of common conditions.