Blepharophimosis-ptosis-epicanthus Inversus Syndrome Research Articles

The mutations and potential targets of the forkhead transcription factor FOXL2

Mutations of FOXL2, a gene encoding a forkhead transcription factor, have been shown to cause the blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). This genetic disorder is characterized by eyelid and mild craniofacial abnormalities that can appear associated with premature ovarian failure. FOXL2 is one of the earliest ovarian markers and it offers, along with its targets, an excellent model to study ovarian development and function in normal and pathological conditions. In this review we summarize recent data concerning FOXL2, its mutations and its potential targets. Indeed, many mutations have been described in the coding sequence of FOXL2. Among them, polyalanine expansions and premature nonsense mutations have been shown to induce protein aggregation. In the context of the ovary, FOXL2 has been suggested to be involved in the regulation of cholesterol and steroid metabolism, apoptosis, reactive oxygen species detoxification and inflammation processes. The elucidation of the impact of FOXL2 mutations on its function will allow a better understanding of the pathogenic mechanisms underlying the BPES phenotype.

FOXL2 mutations in Indian families with blepharophimosis-ptosis-epicanthus inversus syndrome

Blepharophimosis–ptosis–epicanthus inversus syndrome(BPES) (MIM#110100) is an autosomal dominant geneticcondition characterized by a complex eyelid malformation.The main features of BPES are shortening of the horizon-tal palpebral fissures (blepharophimosis), congenital ptosis,telecanthus and epicanthus inversus, and variable expressiv-ity of female infertility (premature ovarian failure) (POF) intype I BPES while absent in type II (Zlotogora

Blepharophimosis–ptosis–epicanthus inversus syndrome: objective analysis of surgical outcome in patients from a single unit

The aim was to objectively assess surgical outcome in blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). Retrospective review of 14 consecutive patients with BPES. Mustardé double z plasty (at about age 4) and autogenous fascia lata Crawford brow suspension (9-12 months later) were used in all. One consultant performed all operations. Patient photographs were scanned and magnified for analysis. Preoperative and postoperative intercanthal distance, vertical palpebral aperture and cosmetic outcome were measured. Values were converted into ratios. Bilateral (mildly asymmetrical) ptosis and symmetrical epicanthic folds were found in all preoperatively. Seventy-one per cent had severe folds. Preoperative intercanthal distance ratio range was 1.26-1.60 (non-BPES=1.0). Median reduction post surgery was 26% (P=0.001, Wilcoxon's signed ranks test). Patients with largest preoperative ratio displayed greatest correction (P=0.029). Mustardé technique completely abolished all epicanthic folds and unmasked prominent caruncles in all. Fifty per cent had mild scarring postoperatively in the medial canthal region. Median change in marginal reflex distance ratio (right)=22.2% (P=0.012), left=18.2% (P=0.008), Wilcoxon's signed ranks tests. Postoperatively all had formed eyelid creases with improved upper lid position symmetry. This is the first known study objectively assessing surgical outcome in BPES. Mustardé double z plasty and Crawford autogenous fascia lata brow suspension are an effective surgical combination in the treatment of this syndrome, with overall cosmetic benefit.

Surgical treament of 13 cases of blepharophimosisptosis-epicanthus inversus syndrome

目的 讨小睑裂综合征的联合手术方法.方法 小睑裂综合征13例26眼,采用三联手术,即上睑提肌缩短术、上睑提肌缩短加横韧带悬吊术、额肌腱膜悬吊术或额肌悬吊术治疗上睑下垂;Spaeth双Z成形术和Y-V成形术治疗内眦赘皮;并进行外眦开大术以扩大睑裂,3项手术一次完成.结果 术后外观有明显改善,睑裂长度和高度显著增加,内眦间距显著缩短.术前睑裂长度19～24 mm,平均(21.0±1.4)mm,睑裂高度:1～4mm,平均(2.3±1.1)mm,内眦间距35～40 mm,平均(37.0±1.6)mm,术后睑裂长度25～30 mm,平均(27.4±1.3)mm.睑裂高度:5～8 mm,平均(6.2±0.9)mm.内眦间距30～35 mm,平均(32.7±1.3)mm,各相应组两两比较差异均有统计学意义(P=0.000).结论 三联手术治疗小睑裂综合征取得良好效果。

Blepharophimosis–ptosis–epicanthus inversus syndrome (BPES)

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is a rare inherited condition that includes characteristic eyelid malformations and sometimes reduced fertility in females. Genetic studies have implicated mutations in the forkhead transcription factor FOXL2 as responsible for BPES. We report a female and her father with BPES type I, who presented the 1092-1108dup17 mutation in the FOXL2 gene. Molecular studies and the typical clinical features of BPES should allow the dermatologist to reach an early diagnosis and permit the treatment of eyelid alterations and the investigation of infertility.

Tamoxifen Treatment in a Patient with Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome and Peripheral Precocious Puberty

Patients with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) can be classified as types 1 or 2, according to the presence or not of ovarian failure. We report a 5 year-old girl with BPES and large multicystic ovaries who developed peripheral precocious puberty with thelarche (Tanner stage III) and pubarche (Tanner stage II). Pelvic ultrasound revealed pubertal uterus and enlarged multicystic ovaries. Fibrous dysplasia and McCune-Albright syndrome were ruled out. Treatment with an estrogen antagonist was started (tamoxifen, 10 mg/day), achieving regression of thelarche. Tamoxifen treatment was stopped at 10-(7/12) years, and growth velocity and skeletal maturation rate returned to normal. No treatment-associated adverse effects were observed.

Mutational screening of FOXO3A and FOXO1A in women with premature ovarian failure

FOXO3A and FOXO1A are excellent candidate genes for the development of premature ovarian failure and have not been analyzed previously in POF patients. Potentially causal mutations in FOXO3A (2/90; 2.2%) and FOXO1A (1/90; 1.1%) were identified in POF patients; however, the pathological role of these mutations will be determined only by screening increased numbers of patients and controls, or by functional studies.

An investigation into FOXE1 polyalanine tract length in premature ovarian failure

Premature ovarian failure (POF) is a common condition affecting 1% of women worldwide. There is strong evidence for genetic involvement in POF as many cases are familial, and mutations in several genes have been associated with POF. We investigated variation in FOXE1 polyalanine tract length, following the observation that polyalanine tract deletions are seen in the closely related FOXL2 in patients with POF. In addition, polyalanine tract expansions in FOXL2 are often seen in patients with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), a rare eyelid disorder often associated with POF. The FOXE1 polyalanine tract shows marked variation in its length between POF patients and normal controls, existing as an allele of 12, 14, 16, 17 or 19 alanine residues. We found evidence to suggest that variation in FOXE1 polyalanine tract length predisposes to POF.

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.

Blepharophimosis and bilateral Duane syndrome associated with a FOXL2 mutation

This case describes the novel coexistence of sporadic blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) and bilateral type I Duane syndrome in a female infant, with a FOXL2 mutation. Mutational analysis of FOXL2 demonstrated a 30-nucleotide duplication (c.672(-)701dup30) within the polyalanine tract of FOXL2. The association of BPES and Duane syndrome represents a novel phenotype which may suggest a greater pleiotropic effect of FOXL2 in development. During the period of the 4-8th week of embryonic development, the cranial nerves, their nuclei and the corresponding innervation to the extraocular muscles develop, the extraocular muscles undergo development and differentiation. This coincides with the period of time that FOXL2 is expressed strongly in the developing eyelids and the surrounding tissues. Forkhead genes are transcription factors and likely to be involved in signal transduction pathways. This case expands the spectrum of FOXL2 mutations associated with BPES.

A new heterozygous mutation of the FOXL2 gene is associated with a large ovarian cyst and ovarian dysfunction in an adolescent girl with blepharophimosis/ptosis/epicanthus inversus syndrome

Blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), an autosomal dominant syndrome in which eyelid malformation is associated with (type I BPES) or without premature ovarian failure (type II BPES). Mutations of a putative winged helix/forkhead transcription factor FOXL2 account for both types of BPES. We report on a 16-year-old adolescent girl with blepharophimosis and ptosis. Subsequently she developed oligomenorrhea, secondary amenorrhea for 6 months, and an extremely large cyst of one ovary. The cyst contained 8 l of cyst fluid and histopathology displayed a large corpus luteum cyst. Following laparotomy, gonadotropin levels were elevated (LH 17.2 U/l, FSH 29.4 U/l) and estradiol levels decreased (67 pmol/l). Because of clinical aspects of BPES and abnormal ovarian function we suspected a mutation of her FOXL2 gene and found a new in-frame mutation (904_939dup36) on one allele, leading to a 12 alanine expansion within the polyalanine domain. We conclude that the FOXL2 mutation 904_939dup36 may account not only for blepharophimosis and ptosis but also for ovarian dysfunction and growth of the large corpus luteum cyst. In contrast to known FOXL2 mutations with polyalanine expansions and association with BPES type II, clinical aspects of our girl may indicate some degree of ovarian dysfunction that might finally lead to BPES type I with premature ovarian failure.

Pisrt1, a gene implicated in XX sex reversal, is expressed in gonads of both sexes during mouse development

XX sex reversal syndromes not involving Sry provide an opportunity to identify and study genes important for sexual development. The polled intersex syndrome (PIS) in goats, which shares some features with blepharophimosis, ptosis, epicanthus inversus syndrome (BPES) in humans, exemplifies such syndromes. BPES is caused by defects in the forkhead transcription factor gene FOXL2, while PIS is caused by a large deletion of goat chromosome 1q43 that affects transcription of the genes Pisrt1 and Foxl2. Pisrt1 is a non-translated gene that has a sexually dimorphic expression pattern in goats. Here, we describe the structure and expression of the mouse Pisrt1 locus, to investigate its likely role in ovarian development more broadly in mammals. This gene showed some sequence similarity, and was found in a similar genomic context, to its goat and human orthologues. Expression analyses indicated that Pisrt1 is transcribed, and its mRNA polyadenylated and exported to the cytoplasm, but no significant open reading frames were found in a 1.5 kb mouse genomic region corresponding to goat Pisrt1. Pisrt1 transcripts were expressed very broadly among tissues of the developing mouse embryo, and at similar levels in male and female gonads at each stage examined, as determined by in situ hybridisation and RT-PCR. This profile of expression suggests that Pisrt1 is unlikely to contribute to sex-specific events during gonadal development in mice and that divergent pathways of ovarian development operate among different mammalian species.

Interstitial deletion in 3q in a patient with blepharophimosis‐ptosis‐epicanthus inversus syndrome (BPES) and microcephaly, mild mental retardation and growth delay: Clinical report and review of the literature

We present a boy with blepharophimosis, ptosis, epicanthus inversus, microcephaly, mild mental retardation, and growth delay. Chromosomal analysis revealed a male karyotype with an interstitial deletion in the long arm of chromosome 3. DNA-analysis showed that the deletion is of maternal origin and encompasses the region between markers D3S1535 and D3S1593. The deletion contains not only the FOXL2 gene, but also the gene encoding ataxia-telangiectasia and Rad3-related protein (ATR). Mutations in FOXL2 have been shown to cause blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). ATR has been identified as a candidate gene for Seckel syndrome, an autosomal recessive syndrome that comprises growth retardation, microcephaly, and mental retardation. We hypothesize that our patient has a contiguous gene syndrome and that the non-BPES-associated abnormalities (microcephaly, mild mental retardation, and growth delay) are the result of the deletion of the maternal ATR gene. However, it has not yet been excluded that haploinsufficiency of some other gene in this region plays a role.

Mutations in the coding region of the FOXL2 gene are not a major cause of idiopathic premature ovarian failure.

Premature ovarian failure (POF) is a heterogeneous disorder whose aetiology is still unknown. Recently, the autosomal FOXL2 gene, highly expressed in the adult ovary, has been correlated with the disorder. FOXL2 mutations, causing a truncation of the FOXL2 protein in the forkhead domain or in the poly-Ala tract lead to blepharophimosis-ptosis-epicanthus-inversus syndrome associated with POF (BPES I). Interestingly, in two out of 70 idiopathic POF patients, a 30 bp deletion (898-927del) and a missense mutation (1009T-->A) were identified. To further evaluate the correlation between POF and FOXL2 mutations, 120 phenotypically normal women affected by POF were analysed by direct sequencing of the FOXL2 coding region. The analysis did not reveal any mutation in the 240 analysed chromosomes, indicating that mutations in the FOXL2 coding region are rarely associated with non-syndromic POF.

A novel insertion mutation in the FOXL2 gene is detected in a big Chinese family with blepharophimosis–ptosis–epicanthus inversus

Blepharophimosis–ptosis–epicanthus inversus syndrome (BPES), an autosomal dominant syndrome in which an eyelid malformation is associated (type I) or not (type II) with premature ovarian failure (POF), has recently been ascribed to mutations in the forkhead transcription factor 2 ( FOXL2) gene. In this work, we reveal a novel insertion mutation in the 3′UTR of the FOXL2 gene in a big Chinese family which is to our knowledge the first BPES (type II) family reported in China. It is the first time that a 3′UTR mutation in the FOXL2 gene has ever been found to demonstrate a close correlation between genotype and BPES. Our result gains a greater insight into the function of 3′UTR in the FOXL2 gene.

Deletion of the TWIST gene in a large five-generation family.

In this article, we describe a large five-generation family with characteristics of the Saethre-Chotzen syndrome as well as of the blepharophimosis ptosis epicanthus inversus syndrome. Segregating with their phenotype is a deletion of the chromosome 7p21 TWIST gene locus. The TWIST gene indeed is involved in Saethre-Chotzen syndrome, a craniosynostosis syndrome further characterized by specific facial and limb abnormalities. However, only two members of our family exhibited craniosynostosis. This report demonstrates that the genetics of craniofacial anomalies are less straightforward than they sometimes appear to be. Not only craniosynostosis, but also subtle facial deformities could be indicative of an abnormality of the TWIST gene. In conclusion, the clinical spectrum of genetic abnormalities of the TWIST gene is highly variable. We therefore recommend that genetic analysis of the TWIST gene locus, including fluorescence in situ hybridization, should be considered in familial cases of facial and eyelid abnormalities without the presence of craniosynostosis.

FOXL2 inactivation by a translocation 171 kb away: analysis of 500 kb of chromosome 3 for candidate long-range regulatory sequences

A translocation breakpoint 171 kb 5′ of the transcription start of FOXL2 causes blepharophimosis/ptosis/epicanthus inversus syndrome (BPES) and associated premature ovarian failure. The breakpoint falls within another gene, MRPS22, that has been sequenced in 500 kb of continuous DNA. MRPS22 encodes 20 exons and a number of alternative transcripts. Three CpG islands (>91% identical) are followed by noncoding exons 4–12 and coding exons 13–20. The 3′UTR extends into the 3′UTR of COPB2. Based on the sequence, three reported translocations that cause BPES all fall within intron 6 of MRPS22. Comparisons reveal conserved segments in introns 6, 11, and 12 of human and mouse. Notably intron 11 sequence is also deleted in goat PIS syndrome (which combines craniofacial defects, female infertility, and XX sex reversal). The conserved sequences are candidates for models in which they are distant enhancers or otherwise affect higher order chromatin structure to impose long-range cis regulation of FOXL2 expression.

The murine winged-helix transcription factor Foxl2 is required for granulosa cell differentiation and ovary maintenance

Human Blepharophimosis/ptosis/epicanthus inversus syndrome (BPES) type I is an autosomal dominant disorder associated with premature ovarian failure (POF) caused by mutations in FOXL2, a winged-helix/forkhead domain transcription factor. Although it has been shown that FOXL2 is expressed in adult ovaries, its function during folliculogenesis is not known. Here, we show that the murine Foxl2 gene is essential for granulosa cell differentiation and ovary maintenance. In Foxl2(lacZ) homozygous mutant ovaries granulosa cells do not complete the squamous to cuboidal transition leading to the absence of secondary follicles and oocyte atresia. We further demonstrate that activin-betaA and anti-Mullerian inhibiting hormone expression is absent or strongly diminished in Foxl2(lacZ) homozygous mutant ovaries. Unexpectedly, two weeks after birth most if not all oocytes expressed Gdf9 in Foxl2(lacZ) homozygous mutant ovaries, indicating that nearly all primordial follicles have already initiated folliculogenesis at this stage. This activation, in the absence of functional granulosa cells, leads to oocyte atresia and progressive follicular depletion. In addition to providing a molecular mechanism for premature ovarian failure in BPES, these results suggest that granulosa cell function is not only crucial for oocyte growth but also to maintain follicular quiescence in vivo.

Etiology of ovarian failure in blepharophimosis ptosis epicanthus inversus syndrome: FOXL2 is a conserved, early-acting gene in vertebrate ovarian development.

Blepharophimosis ptosis epicanthus inversus syndrome (BPES) is a human disorder caused by mutations in the forkhead transcription factor gene FOXL2 and is characterized by facial dysmorphology combined in some cases with ovarian failure. To better understand the role of FOXL2 in the etiology of ovarian failure in BPES, we examined its expression in embryonic ovaries of mice, chickens, and red-eared slider turtles, representatives of three phylogenetically distant vertebrate groups that have different mechanisms of sex determination. Expression of Foxl2 was detected in early ovaries of all three species around the time of sex determination and was associated with both somatic and germ cell populations in mice. Expression was sexually dimorphic in all cases. Sequence analysis of turtle and chicken FoxL2 orthologues indicated an unusually high degree of structural conservation during evolution. FoxL2 was found to be autosomal in chickens, and therefore unlikely to represent the dominant ovarian-determining gene that has been postulated to exist as a possible explanation for female heterogamety in birds. Our observations suggest that BPES may result from early abnormalities in regulating the development of the fetal ovary, rather than premature degeneration of the postnatal or adult ovary. Further, our results suggest that FOXL2 is a highly conserved early regulator of vertebrate ovarian development.

Mutations in FOXL2 underlying BPES (types 1 and 2) in Colombian families.

We report the genetic characterization of one family with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) type 1 and two families with BPES type 2 from a historically isolated population in northwest Colombia. Linkage and haplotype analyses indicate that BPES in these families is linked to 3q23. Mutation screening of FOXL2 in the family with BPES type 1 revealed a novel 394C --> T nonsense mutation which deletes the forkhead DNA binding domain. The two families with BPES type 2 both carry an in-frame 30 bp duplication that leads to the elongation of a polyalanine tract. This duplication has been previously reported in Europe, where recurrent mutation has been demonstrated in unrelated familial and sporadic BPES cases. The recurrent nature of this duplication seems to relate to the secondary structure of this DNA region. The genotype-phenotype correlation seen in the Colombian families is consistent with the recent proposal that BPES type 1 is caused by truncating mutations leading to haploinsufficiency, while BPES type 2 is due to mutations generating elongated protein products.