To identify potential genetic causes for Mayer-Rokitansky-Küster-Hauser syndrome (MRKH), we analyzed blood and rudimentary uterine tissue of 5 MRKH discordant monozygotic twin pairs. Assuming that a variant solely identified in the affected twin or affected tissue could cause the phenotype, we identified a mosaic variant in ACTR3B with high allele frequency in the affected tissue, low allele frequency in the blood of the affected twin, and almost absent in blood of the unaffected twin. Focusing on MRKH candidate genes, we detected a pathogenic variant in GREB1L in one twin pair and their unaffected mother showing a reduced phenotypic penetrance. Furthermore, two variants of unknown clinical significance in PAX8 and WNT9B were identified. In addition, we conducted transcriptome analysis of affected tissue and observed perturbations largely similar to those in sporadic cases. These shared transcriptional changes were enriched for terms associated with estrogen and its receptors pointing at a role of estrogen in MRKH pathology. Our genome sequencing approach of blood and uterine tissue of discordant twins is the most extensive study performed on twins discordant for MRKH so far. As no clear pathogenic differences were detected, research to evaluate other regulatory layers are required to better understand the complex etiology of MRKH.

ObjectiveMayer-Rokitansky-Küster-Hauser syndrome (MRKH) is a rare congenital disease manifesting with aplasia or severe hypoplasia of uterine structures. Even though extensive studies have been performed, for the majority of cases the etiology remains unclear. In this study, we sought to identify genetic causes in discordant monozygotic (MZ) twins using genome sequencing of blood of both twins as well as uterine tissue of the affected twin. In addition, we profiled the endometrial transcriptome of affected twins to compare perturbations with those of sporadic MRKH cases.ResultsFirst, analyzing the data under the assumption that a variant solely identified in the affected twin or affected tissue could cause the phenotype, we identified a mosaic variant in ACTR3B with a high allele frequency in affected tissue, a low allele frequency in blood of the affected twin and almost absent in the blood of the unaffected twin. Since ACTR3B has not been reported for genitourinary anomalies before, clinical relevance of the variant needs to be clarified.Second, examining the data for candidate genes previously implied in MRKH, we detected a pathogenic variant in GREB1L in one twin pair and their unaffected mother showing a reduced phenotypic penetrance. Furthermore, two variants of unknown clinical significance in PAX8 and WNT9B were identified. Analysis for copy number and structural variants revealed no discordant variants in the twins or variants in candidate genes or regions.Third, we conducted transcriptome analysis of affected tissue and observed widespread perturbations largely similar to those in sporadic MRKH cases. These shared transcriptional changes were enriched for terms associated with estrogen and its receptors pointing at a key role of estrogen in MRKH pathology.ConclusionOur study on genome sequencing of blood and uterine tissue of discordant twins is the most extensive study performed on twins discordant for MRKH so far. Nevertheless, no clear pathogenic differences in the twins or between blood and tissue samples were detected. This points towards a more complex etiology of MRKH less dependent on genetic differences and more determined by epigenetic changes or environmental factors. Our transcriptome data showed a clear overlap with gene expression data of sporadic MRKH cases, indicating that the etiology for MRKH in discordant twins and sporadic cases is largely similar.

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Physiotherapy education in Europe must incorporate self-study units in the curriculum due to the bologna reform. Studies investigating the impact of guided self-study (G-SS) on knowledge and skills in pre-clinical Swiss physiotherapy students are scarce. This study protocol describes a prospective randomized feasibility education study that will primarily examine the feasibility of establishing G-SS using retired physiotherapists as tutors in undergraduate physiotherapy students at the Bern University of Applied Sciences, School of Health Professions. Secondary objective will be to evaluate the effectiveness of six G-SS cycles with retired physiotherapists as tutors on knowledge and skills of pre-clinical undergraduate physiotherapy students. Students of the physiotherapy degree course will be allocated into a G-SS group or control group (CG). G-SS consists of an 8-day cycle. Feasibility outcome are the fidelity of implementation that include exposure dosage and students’ responsiveness, and the degree of acceptability. Success criteria of feasibility are (1) exposure dosage calculated as the number of 90-min presentations that are conducted, and the content of cases and competences and (2) students’ responsiveness, with at least a 83% willingness to participate. Acceptability of intervention from the undergraduate students’ perspective will be evaluated by a questionnaire with open, semi-structured questions (post intervention). This study will provide new information regarding the feasibility of embedding G-SS in the curriculum and about the students’ responsiveness and their acceptability for G-SS.Study protocol version 1Trial registration: German Register of Clinical Studies (DKRS: DRKS00015518).