Proposed role for COUP-TFII in regulating fetal Leydig cell steroidogenesis, perturbation of which leads to masculinization disorders in rodents

Reproductive disorders that are common/increasing in prevalence in human males may arise because of deficient androgen production/action during a fetal 'masculinization programming window'. We identify a potentially important role for Chicken Ovalbumin Upstream Promoter-Transcription Factor II (COUP-TFII) in Leydig cell (LC) steroidogenesis that may partly explain this. In rats, fetal LC size and intratesticular testosterone (ITT) increased ~3-fold between e15.5-e21.5 which associated with a progressive decrease in the percentage of LC expressing COUP-TFII. Exposure of fetuses to dibutyl phthalate (DBP), which induces masculinization disorders, dose-dependently prevented the age-related decrease in LC COUP-TFII expression and the normal increases in LC size and ITT. We show that nuclear COUP-TFII expression in fetal rat LC relates inversely to LC expression of steroidogenic factor-1 (SF-1)-dependent genes (StAR, Cyp11a1, Cyp17a1) with overlapping binding sites for SF-1 and COUP-TFII in their promoter regions, but does not affect an SF-1 dependent LC gene (3β-HSD) without overlapping sites. We also show that once COUP-TFII expression in LC has switched off, it is re-induced by DBP exposure, coincident with suppression of ITT. Furthermore, other treatments that reduce fetal ITT in rats (dexamethasone, diethylstilbestrol (DES)) also maintain/induce LC nuclear expression of COUP-TFII. In contrast to rats, in mice DBP neither causes persistence of fetal LC COUP-TFII nor reduces ITT, whereas DES-exposure of mice maintains COUP-TFII expression in fetal LC and decreases ITT, as in rats. These findings suggest that lifting of repression by COUP-TFII may be an important mechanism that promotes increased testosterone production by fetal LC to drive masculinization. As we also show an age-related decline in expression of COUP-TFII in human fetal LC, this mechanism may also be functional in humans, and its susceptibility to disruption by environmental chemicals, stress and pregnancy hormones could explain the origin of some human male reproductive disorders.

Factors influencing success of clinical genome sequencing across a broad spectrum of disorders

To assess factors influencing the success of whole-genome sequencing for mainstream clinical diagnosis, we sequenced 217 individuals from 156 independent cases or families across a broad spectrum of disorders in whom previous screening had identified no pathogenic variants. We quantified the number of candidate variants identified using different strategies for variant calling, filtering, annotation and prioritization. We found that jointly calling variants across samples, filtering against both local and external databases, deploying multiple annotation tools and using familial transmission above biological plausibility contributed to accuracy. Overall, we identified disease-causing variants in 21% of cases, with the proportion increasing to 34% (23/68) for mendelian disorders and 57% (8/14) in family trios. We also discovered 32 potentially clinically actionable variants in 18 genes unrelated to the referral disorder, although only 4 were ultimately considered reportable. Our results demonstrate the value of genome sequencing for routine clinical diagnosis but also highlight many outstanding challenges.

Incidence and significance of the JAK2 V617F mutation in patients with chronic myeloproliferative disorders

BACKGROUND: The chronic myeloproliferative disorders (MPD) are clonal haemopoietic stem cell disorders.

AIMS: The incidence of JAK2 V617F mutation was sought in a population of patients with MPD.

METHODS: The JAK2 V617 mutation status was determined in 79 patients with known MPD and 59 patients with features suggestive of MPD.

RESULTS: The mutation was found in patients with polycythaemia vera, essential thrombocythaemia, idiopathic myelofibrosis and in patients with other chronic myeloproliferative disorders. Eight JAK2 V617F positive cases were identified amongst those patients with features suggestive of MPD.

CONCLUSIONS: The incidence of the JAK2 V617F mutation in MPD patients is similar to that reported by other groups. The assay confirmed and refined the diagnosis of several patients with features indicative of MPD. We suggest screening for this mutation in all patients with known and suspected MPD as identification is valuable in classification and is a potential target for signal transduction therapy.

Review of Protestant Churches and the Formation of Political Consciousness in Southern Mozambique (1930–1974).

Book review of Protestant Churches and the Formation of Political Consciousness in Southern Mozambique (1930–1974). By TERESA CRUZ E SILVA. Introduction by DAVID HEDGES. Basel: P. Schlettwein Publishing, 2001. Pp. xvii+210. CHF 48; €32 (ISBN 3-908193-09-5).

Evaluation of Restorative Dentistry Specialty Registrars’ Clinical Experience of Developmental Disorders: A Survey

Background

Specialty Registrars in Restorative Dentistry (StRs) should be competent in the independent restorative management of patients with developmental disorders including hypodontia and cleft lip/palate upon completion of their specialist training.1 Knowledge and management may be assessed via the Intercollegiate Specialty Fellowship Examination (ISFE) in Restorative Dentistry.2

Objective

The aim of this study was to collate and compare data on the training and experience of StRs in the management of patients with developmental disorders across different training units within the British Isles.

Methods

Questionnaires were distributed to all StRs attending the Annual General Meeting of the Specialty Registrars in Restorative Dentistry Group, Belfast, in October 2015. Participants were asked to rate their confidence and experience of assessing and planning treatment for patients with developmental disorders, construction of appropriate prostheses, and provision of dental implants. Respondents were also asked to record clinical supervision and didactic teaching at their unit, and to rate their confidence of passing a future ISFE station assessing knowledge of developmental disorders.

Results

Responses were obtained from 32 StRs (n=32) training within all five countries of the British Isles. The majority of respondents were based in England (72%) with three in Wales, and two in each of Scotland, Northern Ireland, and the Republic of Ireland. Approximately one third of respondents (34%) were in the final years of training (years 4-6). Almost half of the StRs reported that they were not confident of independently assessing (44%) new patients with a developmental disorder, with larger numbers (72%) indicating a lack of confidence in treatment planning. Six respondents rated their experience of treating obturator patients as ‘poor’ or ‘very poor’. The majority (56%) rated their experience of implant provision in these cases as ‘good’ or ‘excellent’ with three-quarters (75%) rating clinical supervision at their unit as ‘good’ or ‘excellent’. Less than half (41%) rated the didactic teaching at their unit as ‘good’ or ‘excellent’, and only 8 StRs indicated that they were confident of passing an ISFE station focused on developmental disorders.

Conclusion

Experience and training regarding patients with developmental disorders is inconsistent for StRs across the British Isles with a number of trainees reporting a lack of clinical exposure.