Identification of a novel FOXL2 mutation in a single family with both types of blepharophimosis‑-ptosis-epicanthus inversus syndrome

Planned oocyte cryopreservation in women with blepharophimosis-ptosis-epicanthus inversus syndrome: a case series

Objective

To describe the experiences of three women with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) who desired to pursue planned oocyte cryopreservation.

Design

Case series.

Setting

An academic institution and a private clinic.

Patient(s)

Three nulligravid women aged 23, 25, and 34 years who desired to pursue planned oocyte cryopreservation. Two women had BPES diagnosed when they were infants and one had BPES diagnosed after presenting to discuss oocyte cryopreservation.

Intervention(s)

All three women underwent ovarian stimulation. One woman underwent three oocyte retrievals.

Main Outcomes Measure(s)

Vitrification of metaphase II oocytes.

Result(s)

One woman had a total of eight metaphase II oocytes vitrified. In addition, she underwent genetic testing that confirmed type 1 BPES. The other two women, who had BPES diagnosed when they were newborns, each underwent two cycles of ovarian stimulation. Neither of these two women responded to ovarian stimulation and both cycles were cancelled before oocyte retrieval.

Conclusion(s)

BPES is a rare condition that can lead to primary ovarian insufficiency. Early identification of this condition is important to allow for timely reproductive counseling so that oocyte cryopreservation can be offered at a young age before oocyte depletion. Careful counseling is critical for these patients, because this case series demonstrated that not all women with BPES will respond to stimulation. Further, outcomes with cryopreserved oocytes have not yet been described in women with BPES.

The Genetic and Clinical Features of FOXL2-Related Blepharophimosis, Ptosis and Epicanthus Inversus Syndrome

Blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES) is a craniofacial disorder caused by heterozygous variants of the forkhead box L2 (FOXL2) gene. It shows autosomal dominant inheritance but can also occur sporadically. Depending on the mutation, two phenotypic subtypes have been described, both involving the same craniofacial features: type I, which is associated with premature ovarian failure (POF), and type II, which has no systemic features. The genotype-phenotype correlation is not fully understood, but it has been hypothesised that type I BPES involves more severe loss of function variants spanning the whole gene. Type II BPES has been linked to frameshift mutations that result in elongation of the protein rather than complete loss of function. A mutational hotspot has been identified within the poly-alanine domain, although the exact function of this region is still unknown. However, the BPES subtype cannot be determined genetically, necessitating informed genetic counselling and careful discussion of family planning advice in view of the associated POF particularly as the patient may still be a child. Following puberty, female patients should be referred for ovarian reserve and response assessment. Oculofacial features can be managed with surgical intervention and regular monitoring to prevent amblyopia.

New STAT3-FOXL2 pathway and its function in cancer cells

BACKGROUND

The forkhead transcription factor (FOXL2) plays a crucial role in blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), sex determination, ovary growth and development, and cell cycle regulation. Emerging investigations have focused on the downstream targets of FOXL2, while little is known about its upstream regulation.

RESULTS

In this study, we show that FOXL2 could be regulated by STAT3 in cancer cells and that STAT3 binds to FOXL2 at the 5'- GCCTGATGTTTGTCTTCCCAGTCTGTGGCAA-3' site using EMSA and ChIP. We further found that knockdown of STAT3 or FOXL2 could significantly induce cancer cell apoptosis, indicating the importance of these two genes in cancer cell growth and apoptosis. Our data also indicated that the increased apoptotic cell rate may be caused by changes in apoptosis-related genes, such as TNF, TRAIL and GnRHR.

CONCLUSION

This study presents a new upstream regulator of FOXL2 and demonstrats that this new STAT3-FOXL2 pathway has an important function in HeLaHeLa cell apoptosis, providing new insights regarding the targeting of FOXL2 for cancer prevention and treatment.