Prevalence and patient characteristics of Mayer-Rokitansky-Küster-Hauser syndrome: a nationwide registry-based study.

STUDY QUESTION: What is the prevalence of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome?

SUMMARY ANSWER: The prevalence of MRKH syndrome in Denmark is 1 in 4982 (95% confidence interval (CI): 4216-5887) live female births.

WHAT IS KNOWN ALREADY: The prevalence of MRKH syndrome has been estimated to be around 1 in 4000-5000 females. However, population-based prevalence studies of MRKH syndrome are sparse. Moreover, population-based data on patient characteristics are lacking.

STUDY DESIGN, SIZE, DURATION: This retrospective cohort study used the Danish National Patient Registry (DNPR) to identify a nationwide population-based cohort of patients with MRKH syndrome. Subsequently, patients were linked to the Danish Cytogenetic Central Registry (DCCR) and patient medical records in order to validate the diagnoses.

PARTICIPANTS/MATERIALS, SETTING, METHODS: Hospitalizations and outpatient visits from 1994 to April 2015 at all public hospitals in Denmark were searched for patients assigned with a diagnosis code indicative of MRKH syndrome. The diagnoses were validated by diagnostic history in the DNPR and DCCR data, and by review of patient medical records. The prevalence was estimated considering the identified patients born from 1974 to 1996. Patient characteristics were described using data collected from DNPR, DCCR and patient medical records.

MAIN RESULTS AND THE ROLE OF CHANCE: The diagnosis was validated in 304 of 314 patients (96.8%) suspected with MRKH syndrome by review of diagnostic histories, DCCR data, and medical records and in 168 patients, the diagnosis of MRKH syndrome was confirmed (positive predictive value = 55.3% (95% CI: 49.5-60.9%)). The prevalence was 1 in 4982 (95% CI: 4216-5887) live female births based on 138 patients born from 1974 to 1996. Typical MRKH syndrome and atypical MRKH syndrome/Müllerian duct aplasia, Renal aplasia, and Cervicothoracic Somite dysplasia association were present in 56.5% and 43.5% of the patients, respectively. Kidney malformations were the most prevalent extragenital malformations, described in 38 of 111 patients (34.2%). However, in 57 patients (33.9%) no urinary tract imaging was performed. Three familial cases of MRKH syndrome were identified.

LIMITATIONS, REASONS FOR CAUTION: We identified all patients with MRKH syndrome diagnosed at public hospitals in Denmark. When interpreting the prevalence estimate, caution must be taken due to limitations such as patients not diagnosed in public hospitals, other diagnosis codes not used in the study and the unknown impact of a net positive migration rate in Denmark.

WIDER IMPLICATIONS OF THE FINDINGS: The prevalence estimate around 1 in 5000 is in accordance with a previous nationwide study. We consider the prevalence generalizable to other Caucasian populations. Prevalence studies of non-Caucasian populations are needed to investigate whether inter-ethnic differences in prevalence exist. Finally, the results of this study emphasize the need for sufficient basic examinations of patients with MRKH syndrome, including the importance of family medical history.

STUDY FUNDING/COMPETING INTERESTS: None.