Implication of androgen receptor gene dysfunction in human Müllerian duct anomalies

HOXD10: A novel gene implicated in human Müllerian duct anomalies

BACKGROUND

Müllerian duct anomalies (MDAs) are developmental malformations of the female genital tract. Genetic factors linked to MDAs and recent advancements in whole-exome sequencing (WES) have provided innovative perspectives in this field.

METHODS

In total, 97 patients with MDAs were recruited. A novel HOXD10 variant, screened using the in-house database of WES performed in the MDAs cohort, was identified, and its pathogenicity was further assessed using molecular dynamics simulation and functional assays. RNA sequencing was performed to determine the mechanisms underlying pathogenesis.

RESULTS

The HOXD10 c.238A>C (p.S80R) variant was identified in a sporadic patient with complete septate uterus, septate cervix, and longitudinal vaginal septum. This variant was absent in all the 100 controls. The variant was assessed to be pathogenic using in silico algorithms. The HOXD10 S80R variant exhibited conformational alterations compared with the wild type (WT) protein. Both proteins were stable during molecular dynamics simulations. However, S80R exhibited a larger radius of gyration, fewer hydrogen bonds, and an expanded solvent-accessible surface area. RNA sequencing revealed that the inhibition of HOXD10 WT on IFIT1, IFIT2 and IFIT3 were abrogated by S80R variant and resulted in an abnormal cell state.

CONCLUSIONS

To the best of our knowledge, this is the first study to report a novel HOXD10 p.S80R variant and explore its implications in MDAs. Identification of this variant has shed new light on the molecular genetic etiology of MDAs.

POI-associated EIF4ENIF1 mutations exhibit impaired translation regulation abilities

Various genetic variants have been found to be associated with the clinical onset of premature ovarian insufficiency (POI). However, when measured in vitro, the functional influence of the variants can be difficult to determine. By whole-exome sequencing (WES) of 93 patients with sporadic POI, we found a missense variant c.623G > A;p.R208H in the EIF4ENIF1 gene. In silico prediction of the variant using different algorithms suggested it might be a damaging variant. We compared the property of EIF4ENIF1 R208H and Q842P, a POI-related mutant that we reported previously, with wildtype (WT) protein using 293FT cells in vitro. Surprisingly, a change in subcellular distribution and granule forming ability (Q842P) and nuclear import capacity (R208H) was not observed, despite domain prediction evidences. Since EIF4ENIF1 was reported to inhibit translation, we employed T&T-seq, a translation-transcription dual-omics sequencing method, to profile gene expression upon overexpression of EIF4ENIF1 WT and mutants. EIF4ENIF1 WT overexpression group exhibited significantly (P < 0.0001) lower translation efficiency (TE) than empty vector or GFP overexpression control group. Surprisingly, EIF4ENIF1 Q842P overexpression failed to repress global translation, showing an overall TE significantly higher than WT group. Overexpression R208H significantly (P < 0.0001) lowered the overall TE, whereas exhibiting a reduced translation inhibitory effect on high-TE genes (TE > 2 in GFP control group). Several fertility-associated genes, such as AMH in Q842P group and SERPINE1 and THBS1 in R208H group, was translationally up-regulated in mutant groups versus WT control, suggesting a potential mechanism of mutated EIF4ENIF1 causing POI via impaired translation repression. It is further proposed that T&T-seq can be a sensitive evaluation tool for the measurement of functional alteration by variants in many other translational regulator genes, not only EIF4ENIF1, helping to eliminate misinterpretation of clinical significance of genetic variants.