Blepharophimosis-ptosis-epicanthus Inversus Syndrome Patients Research Articles

Clinical characterization and identification of five novel FOXL2 pathogenic variants in a cohort of 12 Mexican subjects with the syndrome of blepharophimosis-ptosis-epicanthus inversus

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant entity characterized by eyelid malformations and caused by mutations in the forkhead box L2 (FOXL2) gene. Clinical and genetic analyses of large cohorts of BPES patients from different ethnic origins are important for a better characterization of FOXL2 mutational landscape. The purpose of this study is to describe the phenotypic features and the causal FOXL2 variants in a Mexican cohort of BPES patients. A total of 12 individuals with typical facial findings were included. Clinical evaluation included palpebral measurements and levator function assessment. The complete coding sequence of FOXL2 was amplified by PCR and subsequently analyzed by Sanger sequencing. A total of 11 distinct FOXL2 pathogenic variants were identified in our cohort (molecular diagnostic rate of 92%), including 5 novel mutations. Our results broaden the BPES-related mutational spectrum and supports considerable FOXL2 allelic heterogeneity in our population.

Co-occurrence of congenital hydronephrosis and FOXL2-associated blepharophimosis, ptosis, epicanthus inversus syndrome (BPES)

Blepharophimosis, ptosis, epicanthus inversus syndrome (BPES) is an autosomal dominantly inherited congenital malformation of the eyelids. Diagnostic criteria include blepharophimosis, ptosis, epicanthus inversus and telecanthus. Type І BPES has additional features of premature ovarian failure and female infertility, while type ІІ occurs isolated. We report a two-year old male child with typical features of BPES and bilateral congenital hydronephrosis. The child, first-born to non-consanguineous parents, presented to us with hypertension. Congenital hydronephrosis and reduced renal function were confirmed by renal dynamic scan. Pyeloplasty and stent placement were performed with subsequent resolution of hypertension. On follow up, growth and development are appropriate for age. His father has similar but less severe features of BPES. Sequencing of the FOXL2 gene revealed a heterozygous FOXL2 mutation c.672_701dup, which is a recurrent 30-bp duplication leading to expansion of the polyalanine tract (p.Ala225_Ala234dup), in both father and son. Additional atypical clinical features have been reported previously in BPES patients with this mutation. However, this is the first report of a renal congenital anomaly in a BPES patient with this or other mutations. Although a pleiotropic effect of the FOXL2 mutation cannot be excluded, the co-occurrence of congenital hydronephrosis and BPES may represent two different entities.

Intragenic and extragenic disruptions of FOXL2 mapped by whole genome low-coverage sequencing in two BPES families with chromosome reciprocal translocation

Blepharophimosis–ptosis–epicanthus inversus syndrome (BPES) is a rare autosomal dominant disorder that affects craniofacial development and ovarian function. FOXL2 is the only gene known to be responsible for BPES. The majority of BPES patients show intragenic mutations of FOXL2. Recently, a 7.4kb sequence disruption, which was 283kb upstream of FOXL2, was identified to independently contribute to the BPES phenotype. Several breakpoints nearing FOXL2 (0Mb to 1.2Mb, several of which were distant from the 7.4kb sequence disruption) have been mapped or deduced through a traditional method in BPES patients with chromosome reciprocal translocation.In this study, two BPES families with chromosome reciprocal translocation were investigated. Intragenic mutations of FOXL2 or pathogenic copy number variations were excluded for the two BPES families. All of the four breakpoints were identified at a base-precise manner using Giemsa banding and whole genome low-coverage sequencing (WGLCS). In family 01, the breakpoints were found at chr1:95,609,998 and chr3:138,879, 114 (213,132bp upstream of FOXL2). In family 02, the breakpoints were located at chr3:138,665,431 (intragenic disruptions of FOXL2) and chr20:56,924,609. Results indicate that the intragenic and extragenic interruptions of FOXL2 can be accurately and rapidly detected using WGLCS. In addition, both the 213kb upstream and intragenic interruptions of FOXL2 can cause BPES phenotype.

Differential Apoptotic and Proliferative Activities of Wild-type FOXL2 and Blepharophimosis-ptosis-epicanthus Inversus Syndrome (BPES)-associated Mutant FOXL2 Proteins

FOXL2 is an essential transcription factor that is required for proper development of the ovary and eyelid. Mutations in FOXL2 cause an autosomal dominant genetic disorder, blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). BPES type I patients have eyelid malformation and premature ovarian failure leading to infertility, whereas women with type II BPES are fertile or subfertile. In the present study, we evaluated and compared apoptotic and antiproliferative activities of wild-type (WT) and mutant FOXL2 proteins found in BPES type I and II in human granulosa cell tumor-derived KGN cells. Ectopic expression of WT FOXL2 induced apoptosis and inhibited cell cycle progression in human granulosa cells. In contrast, mutated FOXL2s found in BPES type I significantly reduced these activities, whereas mutated FOXL2s in BPES type II showed intermediate activities. Furthermore, mutant FOX L2 proteins were defective in activating transcription of target genes including Caspase 8, TNF-R1, FAS, p21, and BMP4, which regulate apoptosis, proliferation, and differentiation of granulosa cells. Thus, decreased apoptotic and antiproliferative activities caused by mutant forms of FOXL2 found in BPES patients may at least partially contribute to the pathophysiology of ovarian dysfunction.

Correction of the Lower Eyelid Malpositioning in the Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant complex eyelid malformation. The authors aim to offer an explanation for the lower eyelid malformation and propose a novel surgical approach to correct it. An observational and interventional case series of 10 consecutive, molecularly proven BPES patients who underwent surgical repair of the lower eyelid malformation. During surgery detailed anatomical examination and surgical repositioning of the medial canthal tendon was performed. All the patients were followed up regularly after the surgery and assessed for epiphora. All patients exhibited a marked asymmetry in the attachment of the lower and upper eyelid to the medial canthal tendon, with the lower eyelid being much less attached. This resulted in an abnormal downward concavity with a temporal ectropion and a temporally displaced lower eyelid. Consequently, the inferior punctum was displaced temporally. All patients underwent a novel surgical technique to remediate this, namely, inserting a 4.0 nylon suture between the tarsal plate of the lower eyelid and the medial canthal tendon during telecanthus surgery. This simple additional surgical step corrected not only the position of the lower eyelid but also its abnormal downward concavity, the temporal ectropion and the lateral displacement of the inferior punctum. None of the authors' patients had lasting epiphora. Lateral displacement of the inferior punctum is an important hallmark in the diagnosis of BPES. The authors demonstrate an anatomical explanation for the complex lower eyelid malformation and also propose a novel surgical technique to correct this. During surgical repair of the telecanthus and blepharophimosis, specific attention should be paid to reattachment of the lower eyelid to the medial canthal tendon. This understanding improves clinical diagnosis and surgical treatment of BPES patients.

A One-Stage Correction of the Blepharophimosis Syndrome Using a Standard Combination of Surgical Techniques

The aim of this study was to evaluate the efficacy of a one-stage treatment for the blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) using a combination of standard surgical techniques. This is a retrospective interventional case series study of 21 BPES patients with a 1-year minimum follow-up period. The one-stage intervention combined three different surgical procedures in the following order: Z-epicanthoplasty for the epicanthus, transnasal wiring of the medial canthal ligaments for the telecanthus, and a bilateral fascia lata sling for ptosis correction. Preoperative and postoperative measurements of the horizontal lid fissure length (HFL), vertical lid fissure width (VFW), nasal intercanthal distance (ICD), and the ratio between the intercanthal distance and the horizontal fissure length (ICD/HFL) were analyzed using Student's t test for paired variables. The mean preoperative measurements were 4.95±1.13mm for the VFW, 20.90±2.14mm for the HFL, 42.45±2.19mm for the ICD, and 2.04±0.14mm for the ICD/HFL ratio. The mean postoperative measurements were 7.93±1.02mm for the VFW, 26.36±1.40mm for the HFL, 32.07±1.96mm for the ICD, and 1.23±0.09mm for the ICD/HFL ratio. All these values and their differences were statistically significant (P<0.0001). All of the patients developed symmetric postoperative inferior version lagophthalmus, a complication that tended to decrease over time. One-stage correction of BPES is safe and efficient with the surgical techniques described.

FOXL2 mutations in Taiwanese patients with blepharophimosis, ptosis, epicanthus inversus syndrome

Blepharophimosis, ptosis, epicanthus inversus syndrome (BPES) is an autosomal dominant developmental disorder that includes an eyelid malformation associated with (type I) or without (type II) premature ovarian failure (POF). Mutations in the forkhead transcription factor 2 (FOXL2) gene, a member of winged/forkhead transcription factor family, are responsible for both types of BPES. The purpose of this study was to identify mutations in FOXL2 in Taiwanese patients with BPES. The karyotype and genomic DNA was prepared from the leukocytes of peripheral venous blood samples. The coding and flanking region sequences of FOXL2 were analyzed by directed or cloning sequencing. The karyotypes of these patients did not show significant variation, especially on the 3q23 region. Two mutations in FOXL2 were identified in two familial cases. One was c.855-871dup (17-bp insertion) associated with POF. The other was c.384G>A (TGG>TGA), a novel mutation that resulted in non-sense changes of the encoded protein, i.e., p.W128X. Our results expand the spectrum of FOXL2 mutations and confirm the mutation hotspot in FOXL2 in Taiwanese BPES patients.

FOXL2 mutations lead to different ovarian phenotypes in BPES patients: Case Report

FOXL2 mutations cause the autosomal dominant Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) that may be associated with premature ovarian failure (POF). However, little is known about the molecular mechanisms of FOXL2 actions in the human ovary. We conducted an extensive clinical, hormonal and ovarian histological study in two patients carrying a FOXL2 mutation associated with the typical eyelid malformations and infertility. This observational study was conducted at referral centres for POF. Histological and immunohistological studies were conducted on ovarian biopsies from two women with POF carrying a FOXL2 mutation resulting in putative polyalanine expansions of the protein. Abnormalities similar to those observed in mice with FOXL2 gene inactivation were present in the first patient's ovary, although the ovarian histology of the second patient was apparently normal. Different ovarian phenotypes, follicular defects and distribution of FOXL2 protein were observed in two patients carrying a FOXL2 mutation.

Functional evidence implicating FOXL2 in non-syndromic premature ovarian failure and in the regulation of the transcription factor OSR2

Background:FOXL2 encodes a forkhead transcription factor whose mutations are responsible for the blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), involving craniofacial/palpebral abnormalities often associated with premature ovarian failure (POF).Results:We describe a FOXL2 variant...

Differential functional effects of novel mutations of the transcription factor FOXL2 in BPES patients

Mutations of the transcription factor FOXL2, involved in cranio-facial and ovarian development lead to the Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome (BPES) in human. Here, we describe nine mutations in the open reading frame of FOXL2. Six of them are novel: c.292T>A (p.Trp98Arg), c.323T>C (p.Leu108Pro), c.650C>G (p.Ser217Cys) and three frameshifts. We have performed localization and functional studies for three of them. We have observed a strong cytoplasmic mislocalization induced by the missense mutation p.Leu108Pro located in the forkhead (FKH) domain of FOXL2. In line with this, transcriptional activity assays confirmed the loss-of-function induced by this variant. Interestingly, the novel mutation p.Ser217Cys, mapping between the FKH and the polyalanine domain of FOXL2 and producing a mild eyelid phenotype, led to normal localization and transactivation. We have also modeled the structure of the FKH domain to explore the potential structural impact of the mutations reported here and other previously reported ones. This analysis shows that mutants can be sorted into two classes: those that potentially alter protein-protein interactions and those that might disrupt the interactions with DNA. Our findings reveal new insights into the molecular effects of FOXL2 mutations, especially those affecting the FKH binding domain. (c) 2008 Wiley-Liss, Inc.

Mutation analysis of the FOXL2 gene in Chinese patients with blepharophimosis–ptosis–epicanthus inversus syndrome

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant disorder characterized by blepharophimosis, ptosis and epicanthus inversus. Based on the presence and absence of premature ovarian failure, two clinical types have been distinguished. Both types of BPES have been mapped to chromosome 3q23 and are mostly due to mutations of a forkhead transcription factor FOXL2 gene which locates at this region. We screened for FOXL2 mutations in Chinese patients with BPES. A novel mutation (g.901-930dup30) which could result in an expansion of the polyalanine tract was found in two BPES type II families and one sporadic case. In addition, a new g.952delC mutation was identified in two patients from a BPES family of undetermined type. The previously reported g.892C>T (p.Q219X) was also found in 12 patients from a large BPES family of type I. No mutations were detected in three other BPES families and three sporadic cases. So we speculate that in a fraction of the BPES patients the genetic defect may represent a change in gene dosage or a rearrangement outside the transcription unit of FOXL2.

Spectrum of FOXL2 gene mutations in blepharophimosis-ptosis-epicanthus inversus (BPES) families demonstrates a genotype--phenotype correlation.

Mutations in FOXL2, a forkhead transcription factor gene, have recently been shown to cause blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) types I and II, a rare genetic disorder. In BPES type I a complex eyelid malformation is associated with premature ovarian failure (POF), whereas in BPES type II the eyelid defect occurs as an isolated entity. In this study, we describe the identification of novel mutations in the FOXL2 gene in BPES types I and II families, in sporadic BPES patients, and in BPES families where the type could not be established. In 67% of the patients studied, we identified a mutation in the FOXL2 gene. In total, 21 mutations (17 of which are novel) and one microdeletion were identified. Thirteen of these FOXL2 mutations are unique. In this study, we demonstrate that there is a genotype--phenotype correlation for either types of BPES by the finding that mutations predicted to result in a truncated protein either lacking or containing the forkhead domain lead to BPES type I. In contrast, duplications within or downstream of the forkhead domain, and a frameshift downstream of them, all predicted to result in an extended protein, cause BPES type II. In addition, in 30 unrelated patients with isolated POF no causal mutations were identified in FOXL2. Our study provides further evidence that FOXL2 haploinsufficiency may cause BPES types I and II by the effect of a null allele and a hypomorphic allele, respectively. Furthermore, we propose that in a fraction of the BPES patients the genetic defect does not reside within the coding region of the FOXL2 gene and may be caused by a position effect.

Fine mapping of the neurally expressed gene SOX14 to human 3q23, relative to three congenital diseases.

Members of the Sox gene family encode transcription factors that have diverse and important functions during development. We have recently described the cloning of chick and mouse Sox14 and the expression of these genes in a population of ventral interneurons in the embryonic spinal cord. We report here the cloning and sequencing of the human orthologue of Sox14. Human SOX14 shows remarkable sequence conservation compared with orthologues from other vertebrate species and probably mirrors the expression of these genes in the developing brain and spinal cord. Using radiation hybrid mapping and fluorescence in situ hybridisation, we have localised SOX14 close to the sequence tagged site D3S1576 on human chromosome 3q23. Three congenital disorders have been localised to this region: blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), Charcot-Marie-Tooth neuropathy type IIB (CMT2B) and Mobius syndrome type 2 (MBS2). We have found that SOX14 is unlikely to be involved in any of these disorders because of the position of SOX14 proximal to a BPES breakpoint and the lack of SOX14 coding region alterations in BPES, CMT2B and MBS2 patients.