Genetics of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome: advancements and implications

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a congenital anomaly characterized by agenesis/aplasia of the uterus and upper part of the vagina in females with normal external genitalia and a normal female karyotype (46,XX). Patients typically present during adolescence with complaints of primary amenorrhea where the diagnosis is established with significant implications including absolute infertility. Most often cases appear isolated with no family history of MRKH syndrome or related anomalies. However, cumulative reports of familial recurrence suggest genetic factors to be involved. Early candidate gene studies had limited success in their search for genetic causes of MRKH syndrome. More recently, genomic investigations using chromosomal microarray and genome-wide sequencing have been successful in detecting promising genetic variants associated with MRKH syndrome, including 17q12 (LHX1, HNF1B) and 16p11.2 (TBX6) deletions and sequence variations in GREB1L and PAX8, pointing towards a heterogeneous etiology with various genes involved. With uterus transplantation as an emerging fertility treatment in MRKH syndrome and increasing evidence for genetic etiologies, the need for genetic counseling concerning the recurrence risk in offspring will likely increase. This review presents the advancements in MRKH syndrome genetics from early familial occurrences and candidate gene searches to current genomic studies. Moreover, the review provides suggestions for future genetic investigations and discusses potential implications for clinical practice.

Clinical presentation and genetics of tricho-rhino-phalangeal syndrome (TRPS) type 1: A single-center case series of 15 patients and seven novel TRPS1 variants

Tricho-rhino-phalangeal syndrome (TRPS) is a rare malformation syndrome characterized by distinctive facial, ectodermal, and skeletal features. TRPS is divided into TRPS type I/III caused by pathogenic variants in TRPS1 and TRPS type II caused by contiguous gene deletions also spanning EXT1 and RAD21. Due to its rarity, knowledge of the clinical course of TRPS remains limited. Therefore, we collected and characterized a case series of 15 TRPS type I patients (median age at diagnosis 15 [interquartile range: 10-18] years, 11 females [73%]) seen at Aarhus University Hospital, Denmark, with a median follow-up period of 10 years. We estimated a minimum point prevalence of 0.5 in 100,000 (95% CI: 0.3-0.8 per 100,000) persons. Common craniofacial features included fine and sparse hair with a high anterior hairline, eyebrows with lateral thinning and a thicker medial part, prominent ears, a bulbous nose tip with small nasal alae, a low-hanging, and often wide columella, and a long philtrum with a thin upper vermillion. Specific skeletal features included short stature and deviating and short fingers with cone-shaped epiphyses and shortened metacarpals on radiographs. The most significant morbidity of the cohort was joint complaints, which were reported by all patients, often already before the TRPS diagnosis was established. We identified ten different TRPS1 variants including both frameshift/nonsense, missense, and splice-site variants, including seven variants not previously reported in the literature. In accordance with previous literature, no genotype-phenotype correlation was identified. The clinical trajectories were heterogeneous involving pediatrics, dermatology, orthopedic surgery, clinical genetics, and/or odontology, emphasizing that close multidisciplinary collaboration is essential for early diagnosis of TRPS and to ensure proper and timely patient care and counseling.

Understanding the Diagnostic Odyssey of Women with Mayer-Rokitansky-Küster-Hauser (MRKH) Syndrome in Denmark: A Qualitative Interview Study

STUDY OBJECTIVE

The diagnosis of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is often a lengthy process that typically occurs during late adolescence. To support optimized and patient-centered care, this study aimed to investigate how women with MRKH syndrome experience the diagnostic process.

METHODS

From January 2021 to March 2021, we conducted in-depth interviews with 18 Danish women (≥25 years) diagnosed with MRKH syndrome. The interviews lasted a median of 92 minutes (range: 67-117). Data were analyzed using thematic analysis.

RESULTS

As teenagers or young women at the time, all women had experienced the diagnostic process in the nonspecialized healthcare sector as deeply upsetting due to distressing gynecological examinations, use of inappropriate language, and considerable diagnostic delay. When reaching the specialized health care sector, questions could finally be answered, but this information and support did not significantly alter their feelings of being "deviant" or "flawed". The women continued their diagnostic odyssey beyond the health care system and found online communities that gave them valuable support in living with MRKH syndrome.

CONCLUSION

Women experience the diagnostic odyssey of MRKH syndrome as upsetting and potentially traumatizing beyond the diagnosis. Healthcare professionals can influence young women's understanding and experience of MRKH syndrome by using inclusive language (eg, avoiding "deformity") and addressing all that is normal and functioning (eg, external genitalia and potential for sexual pleasure). In nonurgent conditions, young women should be given the choice to delay a genital examination.

A life course perspective on Mayer-Rokitansky-Küster-Hauser syndrome: women's experiences and negotiations of living with an underdeveloped uterus and vagina

PURPOSE

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by the absence or underdevelopment of the uterus and upper part of the vagina. It is usually diagnosed during adolescence, and the present study investigates how women experience and negotiate to live with MRKH syndrome long-term.

METHODS

From January to March 2021, eighteen Danish women with MRKH syndrome participated in semi-structured interviews via video conference. The mean time since diagnosis was 11.5 years. A thematic analysis using the life course framework as a theoretical approach was applied.

RESULTS

The analysis identified the diagnosis as a turning point, that dramatically altered the women's imagined futures. Not conforming to dominant social norms regarding sexuality and pregnancy meant that the women continuously managed and negotiated the meaning and impact of MRKH syndrome in relation to the five principles of the life course perspective: (1) Lifelong development, (2) Timing, (3) Human agency, (4) Linked lives, and (5) Historical time and place.

CONCLUSION

Using the life course framework contributed to a holistic understanding of life with MRKH syndrome by showing how the meaning and consequences of the congenital condition changed over time and in adaptation to gendered and age-related social norms and expectations.IMPLICATIONS FOR REHABILITATIONThe perceived meaning and impact of living with Mayer-Rokitansky-Küster-Hauser syndrome change over time, and women's information and support needs thus change accordinglySensitive, clinical communication is essential when discussing treatment optionsOnline communities may provide support and reduce feelings of loneliness.

Congenital mirror movements are associated with defective polymerisation of RAD51

BACKGROUND

Mirror movements are involuntary movements of one hand that mirror intentional movements of the other hand. Congenital mirror movements (CMM) is a rare genetic disorder with autosomal dominant inheritance, in which mirror movements are the main neurological manifestation. CMM is associated with an abnormal decussation of the corticospinal tract, a major motor tract for voluntary movements. RAD51 is known to play a key role in homologous recombination with a critical function in DNA repair. While RAD51 haploinsufficiency was first proposed to explain CMM, other mechanisms could be involved.

METHODS

We performed Sanger sequencing of RAD51 in five newly identified CMM families to identify new pathogenic variants. We further investigated the expression of wild-type and mutant RAD51 in the patients' lymphoblasts at mRNA and protein levels. We then characterised the functions of RAD51 altered by non-truncating variants using biochemical approaches.

RESULTS

The level of wild-type RAD51 protein was lower in the cells of all patients with CMM compared with their non-carrier relatives. The reduction was less pronounced in asymptomatic carriers. In vitro, mutant RAD51 proteins showed loss-of-function for polymerisation, DNA binding and strand exchange activity.

CONCLUSION

Our study demonstrates that RAD51 haploinsufficiency, including loss-of-function of non-truncating variants, results in CMM. The incomplete penetrance likely results from post-transcriptional compensation. Changes in RAD51 levels and/or polymerisation properties could influence guidance of the corticospinal axons during development. Our findings open up new perspectives to understand the role of RAD51 in neurodevelopment.

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome: a comprehensive update

BACKGROUND

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, also referred to as Müllerian aplasia, is a congenital disorder characterized by aplasia of the uterus and upper part of the vagina in females with normal secondary sex characteristics and a normal female karyotype (46,XX).

MAIN BODY

The diagnosis is often made during adolescence following investigations for primary amenorrhea and has an estimated prevalence of 1 in 5000 live female births. MRKH syndrome is classified as type I (isolated uterovaginal aplasia) or type II (associated with extragenital manifestations). Extragenital anomalies typically include renal, skeletal, ear, or cardiac malformations. The etiology of MRKH syndrome still remains elusive, however increasing reports of familial clustering point towards genetic causes and the use of various genomic techniques has allowed the identification of promising recurrent genetic abnormalities in some patients. The psychosexual impact of having MRKH syndrome should not be underestimated and the clinical care foremost involves thorough counselling and support in careful dialogue with the patient. Vaginal agenesis therapy is available for mature patients following therapeutical counselling and education with non-invasive vaginal dilations recommended as first-line therapy or by surgery. MRKH syndrome involves absolute uterine factor infertility and until recently, the only option for the patients to achieve biological motherhood was through gestational surrogacy, which is prohibited in most countries. However, the successful clinical trial of uterus transplantation (UTx) by a Swedish team followed by the first live-birth in September, 2014 in Gothenburg, proofed the first available fertility treatment in MRKH syndrome and UTx is now being performed in other countries around the world allowing women with MRKH syndrome to carry their own child and achieve biological motherhood.

CONCLUSION

Several advances in research across multiple disciplines have been made in the recent years and this kaleidoscopic review provides a current status of various key aspects in MRKH syndrome and provides perspectives for future research and improved clinical care.