Mayer-Rokitansky-Ku ¨ster-Hauser syndrome (MRKHS) is associated with congenital absence of the uterus, cervix, and the upper part of the vagina; it is a sex-limited trait. Disrupted development of the Mu ¨llerian ducts (MD)/Wo ¨lffian ducts (WD) through multifactorial mechanisms has been proposed to underlie MRKHS. In this study, exome sequencing (ES) was performed on a Chinese discovery cohort (442 affected subjects and 941 female control subjects) and a replication MRKHS cohort (150 affected subjects of mixed ethnicity from North America, South America, and Europe). Phenotypic follow-up of the female reproductive system was performed on an additional cohort of PAX8-associated congenital hypothyroidism (CH) (n ¼ 5, Chinese). By analyzing 19 candidate genes essential for MD/WD development, we identified 12 likely gene-disrupting (LGD) variants in 7 genes:, and WNT9B (n ¼ 1), while LGD variants in these genes were not detected in control samples (p ¼ 1.27EÀ06). Interestingly, a sex-limited penetrance with paternal inheritance was observed in multiple families. One additional PAX8 LGD variant from the replication cohort and two missense variants from both cohorts were revealed to cause loss-of-function of the protein. From the PAX8-associated CH cohort, we identified one individual presenting a syndromic condition characterized by CH and MRKHS (CH-MRKHS). Our study demonstrates the comprehensive utilization of knowledge from developmental biology toward elucidating genetic perturbations, i.e., rare pathogenic alleles involving the same loci, contributing to human birth defects.Mayer-Rokitansky-Ku ¨ster-Hauser syndrome (MRKHS [MIM: 277000]), also referred to as Mu ¨llerian aplasia, is characterized by congenital absence of the uterus, cervix, and upper part of the vagina in females with a normal karyotype (46, XX). 1 With an incidence of 1 in 4,500-5,000 newborn females, MRKHS is the second most common cause of primary amenorrhea after gonadal dysgenesis. 2 MRKHS is further divided into MRKHS type I (isolated) and MRKHS type II (syndromic) according to the presence of multi-organ involvement. 3 Formation and morphogenesis of the Mu ¨llerian ducts take place during weeks 5-6 of human embryogenesis
A lower proportion of associated malformations were found when compared with those provided in the current literature. Renal anomalies were the most frequent associated malformations, and most of the patients presented with a normal karyotype. Given the large cohort of this study, the lower malformation rates might be related to geographic or referral patterns, so further investigation is warranted.
Objective
The aim of this study was to use whole genome sequencing (WGS) help detect
de novo
mutations or pathogenic genes of Mayer-Rokitansky-Küster-Hauser syndrome type 1(MRKH syndrome type 1).
Study design
This was a case-parent trios study. Nine unrelated probands, with MRKH syndrome type 1 and their parents were enrolled. The enrollment, sequencing process, establishment of the
de novo
mutations detecting procedure and experiment part were performed over a 2-year period.
Results
we detected 632
de novo
single nucleotide variants (SNVs), 267
de novo
small insertions/deletions (indels), 39
de novo
structural variations (SVs) and 28 de novo copy number alterations (CNAs). Three novel damaging coding
de novo
SNVs with three damaging coding
de novo
genes (PIK3CD, SLC4A10 and TNK2) were revealed. Two SNVs were annotated of the promoter region of gene NBPF10 and 3'UTR of NOTCH2NL, potentially contributing to the pathogenesis of MRKH.
Conclusion
We identified five
de novo
mutations in BAZ2B, KLHL18, PIK3CD, SLC4A10 and TNK2 by performing WGS, the functional involvement of all deleterious mutations in MRKH candidate genes of the trios warrant further study. WGS may complement conventional array to capture the complete landscape of the genome in MRKH.
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