Development of the Mullerian system, which forms the fallopian tubes, uterus and upper vagina, occurs intertwined with development of the urinary tract. Mullerian anomalies occur in 5–7% of women and interfere with reproductive function (Layman, 2014). The most severe form is congenital absence of the uterus and vagina, also known as Mullerian aplasia and Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH). MRKH is often classified as type 1 (isolated Mullerian aplasia) and type 2 (associated anomalies—unilateral renal agenesis, skeletal, cardiac, and auditory defects) (Oppelt et al., 2012).

MRKH affects ∼1/5000 women (Aittomaki et al., 2001,Herlin et al., 2016) and is the second most common cause of primary amenorrhea (Reindollaret al., 1981). The molecular pathways of Mullerian development have been well-studied in nonhuman animal models, and multiple genes have been implicated including genes involved in WNT and retinoic acid receptor signaling (Masse et al., 2009). However, the molecular pathophysiology of MRKH syndrome remains largely unknown. A genetic basis has been supported by family studies with >1 affected person (Herlin et al., 2014, Williams et al., 3rd). Autosomal dominant inheritance with reduced penetrance or sex-limited inheritance has been suggested based upon available pedigrees (Herlin et al., 2014, Williams et al., 3rd).

Single nucleotide variants and copy number variants (CNVs) have been reported in persons with MRKH (Nik-Zainal et al., 2011). To date in OMIM, heterozygous WNT4 (MIM 158330) and HNF1B (MIM 137920) pathogenic variants have been found in 1–2% of affected individuals (Williams et al., 3rd, Biason-Lauber et al., 2004; Lindner et al., 1999; Mikhael et al., 3rd). Other reported involved genes include GREB1L (MIM 617805) (Herlin et al., 2019) and PAX8, contained within a 10.79 Mb interstitial deletion of 2q13q14.2 (Ma et al., 2014), Repetitive CNVs of 17q12, 16p11.2 and 22q11 have been reported in 5–8% of patients, but they contain many genes and the phenotypic manifestations are variable (Layman, 2014; Nik-Zainal et al., 2011). We hypothesized that heterozygous pathogenic variants in individuals with MRKH, either de novo or inherited, particularly within the 17q12 and 16p11 genomic regions, could be present. We utilized next generation sequencing methods to investigate the molecular basis of MRKH.