Meibography-Guided Electroepilation for Congenital Distichiasis: A Novel Surgical Technique.

PURPOSE: Congenital distichiasis is managed either by ablation, using laser, cryotherapy, or electroepilation, or by surgical excision with mucous membrane grafting. Ablative procedures are usually blind as the exact depth of distichiatic eyelashes is unknown. The described surgical technique utilizes meibography for imaging the root and depth of distichiatic eyelashes that aided in performing electroepilation. METHODS: Six patients (n = 24 eyelids; mean age 15.5 ± 12.2 years) underwent infrared meibography (Oculus Keratograph 5 M) and noninvasive tear breakup time prospectively. Eyelashes were electroepilated using a premarked needle inserted at a depth based on meibography findings in 4 patients. Surgical success was defined as no distichiatic eyelash regrowth and functional success was defined as the resolution of symptoms at a minimum of 3 months of follow-up. RESULTS: All 6 patients had all 4 eyelids involved to varying degrees, with a total of 230 distichiatic eyelashes. The median number of distichiatic eyelashes was 9 in the upper eyelids and 4.5 in the lower eyelids. Meibography revealed visible distichiatic eyelash roots in 70% of eyelashes in the upper eyelid and 87.8% in the lower eyelid, respectively. The median eyelash root depth was 2.7 mm (mean 2.9 mm, range 1.8-5.4 mm). The mean noninvasive tear breakup time was 12.2 seconds despite absent or rudimentary meibomian gland segments seen on meibography. The anatomical success was 75% (12/16 eyelids), and functional success was 87.5% (7/8 eyes) at a median follow-up of 5.5 months. CONCLUSION: Preoperative infrared meibography in eyelids with congenital distichiasis helps estimate the eyelash depth and can be used to guide eyelash ablation procedures.

Ophtalmologic diagnosis of lymphedema-distichiasis syndrome through the FOXC2 mutation.

Lymphedema distichiasis syndrome is one of the most frequent phenotypes of primary lymphedema, even so, its prevalence is still low. This syndrome courses with the appearance of abnormal eyelashes and distichiasis during childhood or puberty. This can cause a notable discomfort on our patients, especially at such an early age. The clinic evaluation of this signs must make us have in mind this group of syndromes, because in the case of lymphedema distichiasis syndrome, we can certainly diagnose it with the genetic analysis of the FOXC2 gen on patient's serum. With this we could prevent, diagnose and treat the ophthalmologic syndrome alongside the rest of systemic symptoms of this syndrome in a more effective way, giving our patients a higher quality of life.

Genetic landscape of FOXC2 mutations in lymphedema-distichiasis syndrome: Different mechanism of pathogenicity for mutations in different domains.

Lymphedema-dissociated syndrome (LDS), of which the pathogenesis is not fully understood, afflicts many patients. In this study, we investigated the effect of FOXC2 gene loss-of-function on the development of LDS disease. Two Han Chinese families with LDS were recruited in this study, pathogenic mutations were identified by Sanger sequencing. Reverse-transcription PCR, subcellular localization, dual fluorescein enzymes, and other in vitro experiments were used to study the functional effects of eight FOXC2 mutations. Two pathogenic FOXC2 duplication mutations (c.930_936dup and c.931-937dup) were identified in the two families. Both mutations caused uneven distribution in the nucleus and a chromatin contraction phenotype, weakening the DNA binding activity and transcription activity. We then performed functional analysis on six additional mutations in different domains of FOXC2 that were reported to cause LDS. We found mutations located in the forkhead domain and central region dramatically reduced the transactivation ability, while mutations in activation domain-2 enhanced this ability. All 8 mutations down-regulated the transcription of ANGPT2 and affected the activity of the ERK-RAS pathway, which may cause abnormal formation of lymphatic vessels. Our findings also showed that all 8 mutations decreased the ability of interaction between FOXC2 and the Wnt4 promoter, suggesting mutations in FOXC2 may also affect the Wnt4-Frizzled-RYK signaling pathway, leading the abnormal differentiation of the meibomian glands into hair follicle cells during the embryonic period and causing distichiasis. This study expanded and revealed the potential pathogenesis mechanism.

Microdeletion of 16q24.1-q24.2-A unique etiology of Lymphedema-Distichiasis syndrome and neurodevelopmental disorder.

Interstitial deletions of 16q24.1-q24.2 are associated with alveolar capillary dysplasia, congenital renal malformations, neurodevelopmental disorders, and congenital abnormalities. Lymphedema-Distichiasis syndrome (LDS; OMIM # 153400) is a dominant condition caused by heterozygous pathogenic variants in FOXC2. Usually, lymphedema and distichiasis occur in puberty or later on, and affected individuals typically achieve normal developmental milestones. Here, we describe a boy with congenital lymphedema, distichiasis, bilateral hydronephrosis, and global developmental delay, with a de novo microdeletion of 894 kb at 16q24.1-q24.2. This report extends the phenotype of both 16q24.1-q24.2 microdeletion syndrome and of LDS. Interestingly, the deletion involves only the 3'-UTR part of FOXC2.

Distichiasis: An update on etiology, treatment and outcomes.

Distichiasis, an extra row of eyelashes emerging from meibomian gland orifices, occurs due to the metaplastic transition of sebaceous glands into the pilosebaceous unit. It can present congenitally, such as in lymphedema distichiasis syndrome, or secondary to acquired conditions, such as cicatrizing conjunctivitis, trachoma. This review summarizes the etiology of distichiasis, its presentation, the evolution of various surgical techniques, and their outcomes in human and animal eyes. The published literature has focused on the different treatment modalities and their outcomes; the etiopathogenesis of this condition remains elusive. Truncating mutations (missense, frameshift, and nonsense) in the Forkhead family gene FOXC2 are involved in the distichiasis-lymphedema syndrome. The treatment options are no different for congenital versus acquired distichiasis, with no specific available algorithms. Acquired distichiasis in cicatrizing ocular surface diseases is difficult to manage, and existing treatment options offer success rates of 50%-60%. The outcomes of electroepilation or direct cryotherapy are not as good as surgical excision of distichiatic lashes after splitting the anterior and posterior lamella under direct visualization. The marginal tarsectomy with or without free tarsoconjunctival graft has shown good results in eyes with congenital and acquired distichiasis. The details of differences between normal and distichiatic lash, depth, or course of distichiatic eyelashes remain largely unknown. Studies exploring the distichiatic eyelash depth might improve the outcomes of blind procedures such as cryotherapy or radiofrequency-assisted epilation.

Compound genetic etiology in a patient with a syndrome including diabetes, intellectual deficiency and distichiasis.

BACKGROUND: We studied a young woman with atypical diabetes associated with mild intellectual disability, lymphedema distichiasis syndrome (LDS) and polymalformative syndrome including distichiasis. We used different genetic tools to identify causative pathogenic mutations and/or copy number variations. RESULTS: Although proband's, diabetes mellitus occurred during childhood, type 1 diabetes was unlikely due to the absence of detectable autoimmunity. DNA microarray analysis first identified a de novo, heterozygous deletion at the chr16q24.2 locus. Previously, thirty-three pathogenic or likely pathogenic deletions encompassing this locus have been reported in patients presenting with intellectual deficiency, obesity and/or lymphedema but not with diabetes. Of note, the deletion encompassed two topological association domains, whose one included FOXC2 that is known to be linked with LDS. Via whole-exome sequencing, we found a heterozygous, likely pathogenic variant in WFS1 (encoding wolframin endoplasmic reticulum [ER] transmembrane glycoprotein) which was inherited from her father who also had diabetes. WFS1 is known to be involved in monogenic diabetes. We also found a likely pathogenic variant in USP9X (encoding ubiquitin specific peptidase 9 X-linked) that is involved in X-linked intellectual disability, which was inherited from her mother who had dyscalculia and dyspraxia. CONCLUSIONS: Our comprehensive genetic analysis suggested that the peculiar phenotypes of our patient were possibly due to the combination of multiple genetic causes including chr16q24.2 deletion, and two likely pathogenic variants in WFS1 and USP9X.

Cryptophthalmos, dental anomalies, oral vestibule defect, and a novel FREM2 mutation.

FREM2 is a member of the FREM2-FRAS1-FREM1 protein complex which contributes to epithelial-mesenchymal coupling. We report a Thai woman with cryptophthalmos, dental anomalies, and oral vestibule defect. A compound heterozygous mutation (c.6499C>T; p.Arg2167Trp and c.641_642del; p.Glu214GlyfsTer135) in the FREM2 gene was identified. The frameshift variant p.Glu214GlyfsTer135 is de novo and novel. It is predicted to result in the loss of most of the functional domains. The p.Arg2167Trp mutation was predicted to disrupt both Ca2+ binding and conformational change. The Arg2167Trp mutant protein has been shown to cause partial loss of function, decrease its interaction with FREM1 and result in impaired function of the FRAS1-FREM2-FREM1 complex. Frem2 was shown to be expressed in the developing tooth and vestibular lamina. It is hypothesized that these mutations resulted in aberration of the FRAS1-FREM2-FREM1 protein complex, resulting in loss of nephronectin, basement membrane disruption, and abnormal epithelial-mesenchymal interactions leading to dental and oral vestibule malformations.

Imbalance between Expression of FOXC2 and Its lncRNA in Lymphedema-Distichiasis Caused by Frameshift Mutations.

Forkhead-box C2 (FOXC2) is a transcription factor involved in lymphatic system development. FOXC2 mutations cause Lymphedema-distichiasis syndrome (LD). Recently, a natural antisense was identified, called lncRNA FOXC2-AS1, which increases FOXC2 mRNA stability. No studies have evaluated FOXC2 and FOXC2-AS1 blood expression in LD and healthy subjects. Here, we show that FOXC2 and FOXC-AS1 expression levels were similar in both controls and patients, and a significantly higher amount of both RNAs was observed in females. A positive correlation between FOXC2 and FOXC2-AS1 expression was found in both controls and patients, excluding those with frameshift mutations. In these patients, the FOXC2-AS1/FOXC2 ratio was about 1:1, while it was higher in controls and patients carrying other types of mutations. The overexpression or silencing of FOXC2-AS1 determined a significant increase or reduction in FOXC2 wild-type and frameshift mutant proteins, respectively. Moreover, confocal and bioinformatic analysis revealed that these variations caused the formation of nuclear proteins aggregates also involving DNA. In conclusion, patients with frameshift mutations presented lower values of the FOXC2-AS1/FOXC2 ratio, due to a decrease in FOXC2-AS1 expression. The imbalance between FOXC2 mRNA and its lncRNA could represent a molecular mechanism to reduce the amount of FOXC2 misfolded proteins, protecting cells from damage.

Successful treatment of distichiasis in a cow using a direct-contact 810-nm diode laser.

OBJECTIVES: To describe the use of direct-contact diode laser as a new treatment for distichiasis. STUDY DESIGN: Case report. ANIMALS: A 2-month-old Italian Friesian calf with bilateral excessive tearing and corneal opacification was presented to the Visionvet Eye Clinic. Abnormalities on ophthalmic examination included epiphora, seromucous discharge, bilateral distichiasis and secondary chronic keratitis affecting both eyes. METHODS: Distichiae were surgically removed after insertion of the 810-nm diode laser tip into the associated meibomian gland. RESULTS: Clinical signs gradually improved postoperatively with minimal and transient post-operative complications. Ophthalmic examination was within normal limits 6 months later beyond distichiae. CONCLUSION: Treatment of distichiasis with direct-contact 810-nm diode laser resulted in long-term resolution of signs in the case described here.

Lymphedema distichiasis syndrome may be caused by FOXC2 promoter-enhancer dissociation and disruption of a topological associated domain.

Lymphedema distichiasis syndrome (LDS) is a rare autosomal dominant condition characterized by lower limb lymphedema, distichiasis, and variable additional features. LDS is usually caused by heterozygous sequence variants in the FOXC2 gene located at 16q24, but in one previous instance LDS has resulted from a balanced reciprocal translocation with a breakpoint at 16q24, 120 kb distal to the FOXC2 gene suggesting a position effect. Here, we describe a second family with LDS caused by a translocation involving 16q24. The family were ascertained after detection of a paternally inherited balanced reciprocal translocation t(16;22)(q24;q13.1) in a pregnancy complicated by severe fetal hydrops. There was a past history of multiple miscarriages in the father's family, and a personal and family history of lymphedema and distichiasis, consistent with the diagnosis of LDS. Using whole genome amplified DNA from single sperm of the male proband, bead array analysis demonstrated that the FOXC2 gene was intact and the chromosome 16 breakpoint mapped to the same region 120Kb distal to the FOXC2 gene. This case highlights the clinical consequences that can arise from a translocation of genomic material without dosage imbalance, and that it is increasingly feasible to predict and characterize possible effects with improved access to molecular techniques.

[Genetic analysis and clinical phenotype of a family with lymphedema-distichiasis syndrome].

OBJECTIVE: To identify the genetic causes of a family with lymphedema-distichiasis syndrome (LDS). METHODS: The whole exome sequencing was performed in a aborted fetus as the proband, and a candidate gene was identified. Peripheral blood of 8 family members were collected. Genotypic-phenotypic analysis were carried out through PCR amplification and Sanger sequencing. RESULTS: The proband, and the mother, grandmother, uncle, granduncle of the proband all had distichiasis or varix of lower limb carried a FOXC2:c.595dupC frame shift mutation, and other subjects without any significant phenotypes did not present the mutation. CONCLUSIONS: The FOXC2:c.595dupC frame shift mutation is the genetic cause of this family, which can lead to autosomal dominantly LDS, presenting nuchal translucency thickening and hydrops fetal during pregnancy, and the prognosis is usually good.

FOXC2 Disease Mutations Identified in Lymphedema Distichiasis Patients Impair Transcriptional Activity and Cell Proliferation.

FOXC2 is a member of the human forkhead-box gene family and encodes a regulatory transcription factor. Mutations in FOXC2 have been associated with lymphedema distichiasis (LD), an autosomal dominant disorder that primarily affects the limbs. Most patients also show extra eyelashes, a condition known as distichiasis. We previously reported genetic and clinical findings in six unrelated families with LD. Half the patients showed missense mutations, two carried frameshift mutations and a stop mutation was identified in a last patient. Here we analyzed the subcellular localization and transactivation activity of the mutant proteins, showing that all but one (p.Y109*) localized to the nucleus. A significant reduction of transactivation activity was observed in four mutants (p.L80F, p.H199Pfs*264, p.I213Tfs*18, p.Y109*) compared with wild type FOXC2 protein, while only a partial loss of function was associated with p.V228M. The mutant p.I213V showed a very slight increase of transactivation activity. Finally, immunofluorescence analysis revealed that some mutants were sequestered into nuclear aggregates and caused a reduction of cell viability. This study offers new insights into the effect of FOXC2 mutations on protein function and shows the involvement of aberrant aggregation of FOXC2 proteins in cell death.

[Genetic variant analysis of a pedigree affected with lymphedema-distichiasis syndrome].

OBJECTIVE: To analyze FOXC2 gene variant in a family affected with lymphodema-distichiasis syndrome (LDS). METHODS: Peripheral blood samples were collected for the extraction of DNA and protein. Whole-exome sequencing was carried out to detect variants in the proband. Suspected variant was validated by Sanger sequencing. Western blotting was used to detect changes in protein expression. RESULTS: The proband and his mother were both found to carry a heterozygous nonsense variant c.177C>G (p.Tyr59X) of the FOXC2 gene, which was previously unreported. Down-regulated expression of FOXC2 was detected by Western blotting. Prenatal ultrasonography of the fetus indicated increased nuchal thickness. Amniocentesis was performed at 21+1 weeks of pregnancy, genetic testing suggested that the fetus also carried the c.177C>G variant. CONCLUSION: The patients' condition may be attributed to the heterozygous nonsense variant c.177C>G of the FOXC2 gene, which resulted in a significant decrease in FOXC2 expression. Increased nuchal thickness may also be related with decreased FOXC2 expression. Above finding has expanded the variant spectrum of the FOXC2 gene.

Evaluation of partial tarsal plate excision using a transconjunctival approach for the treatment of distichiasis in dogs.

PURPOSE: To evaluate the clinical outcome, possible complications, and recurrence rate of distichiasis in dogs treated with partial tarsal plate excision (PTPE) technique using a transconjunctival approach. METHODS: Retrospective study including 17 client-owned canine patients affected with distichiasis and presenting with associated clinical signs (ie, blepharospasm, epiphora, chronic keratoconjunctivitis, or corneal ulceration) that underwent surgical removal of the aberrant lashes using a PTPE technique between January 2018 and February 2019. Data collected included breed, age, sex, affected eyelid(s), number of distichia, and tear film breakup time (TBUT). Resected cilia-bearing tarsoconjunctival strips were submitted for histopathological analysis. RESULTS: Thirty eyes (52 eyelids) from 17 dogs were included in the study. The median age was 688 days (range 118-4243 days). A successful outcome, defined as complete resolution of clinical signs attributable to the distichia, occurred in all eyes after a single procedure, with a mean follow-up time of 239 days (range 69-480 days). Appearance of new distichia occurred in 14/30 eyes (46.3%), and of these, three eyes needed a new PTPE procedure. Recurrence of the distichia only occurred in one eye (3.3%) which was asymptomatic. Following surgery, TBUT decreased below the normal value in 7/24 eyes (29.1%) although none developed clinical signs of qualitative tear film deficiency. Post-operative complications included trichiasis and cicatricial entropion, which developed in two eyes (6.6%), and these were successfully managed with corrective eyelid surgery. CONCLUSIONS: Partial tarsal plate excision, using a transconjunctival approach, had an excellent clinical outcome with a low incidence of complications.

The utility of exome sequencing for fetal pleural effusions.

OBJECTIVE: We sought to evaluate the performance of exome sequencing (ES) in determining an underlying genetic etiology for cases of fetal pleural effusions. STUDY DESIGN: We examined a prospective cohort series of fetal pleural effusions visualized sonographically between 1 April 2016 and 31 August 2017. Fetal pleural effusions attributed to twin sharing, anemia, or structural anomalies were excluded, as were all cases with a genetic diagnosis established by karyotype or chromosomal microarray analysis. The remaining cases with pleural effusions of unclear etiology were offered ES. ES was performed by clinical sequencing and/or sequencing under the Baylor-Hopkins Center for Mendelian Genomics' (BHCMG) research platform. All cases were evaluated for novel genes or phenotypic expansion of disease-causing genes. RESULTS: ES was performed on six probands affected by pleural effusions. A pathogenic variant was identified in one case (16.7%). Four additional cases had variants of uncertain significance (VUS) in candidate genes of pathological interest. Neither clinical nor candidate genes were evident in the final case. CONCLUSION: ES should be considered in the evaluation of prenatally detected idiopathic pleural effusions when other diagnostic workup for a genetic etiology has failed.

Lymphoscintigraphic Abnormalities Associated with Milroy Disease and Lymphedema-Distichiasis Syndrome.

Background: Primary lymphedema is genetically heterogeneous. Two of the most common forms of primary lymphedema are Milroy disease (MD) and lymphedema-distichiasis syndrome (LDS). This study aims to look further into the pathogenesis of the two conditions by analyzing the lymphoscintigram images from affected individuals to ascertain if it is a useful diagnostic tool. Methods and Results: The lymphoscintigrams of patients with MD and LDS were analyzed, comparing the images and transport parameters of the two genotypes against a control population. Lymphoscintigrams were available for 12 MD and 16 LDS patients (all genetically proven diagnoses). Eight of the 12 (67%) lymph scans performed on patients with MD demonstrated little or no uptake from the initial lymphatics and poor visualization of the inguinal lymph nodes. These changes were consistent with a "functional aplasia," that is, the lymphatic vessels were present but appeared to be ineffective in absorbing the interstitial fluid into the lymphatic system. In patients with LDS the lymphoscintigraphic appearances were different. In 12 of the 16 scans (75%), the lymph scans were highly suggestive of lymphatic collector reflux. Quantification revealed a significantly reduced uptake of tracer within the inguinal lymph nodes and a higher residual activity in the feet at 2 hours in MD compared with LDS and compared with controls. Conclusion: Lymphoscintigraphic imaging and quantification can be characteristic in specific genetic forms of primary lymphedema and may be useful as an additional tool for in-depth phenotyping, leading to a more accurate diagnosis and providing insight into the underlying mechanism of disease.

Trichomegaly induced by topical tacrolimus for the treatment of periorbital vitiligo: A brief report of a new adverse effect.

Trichomegaly is a known adverse effect of systemic administration of cyclosporine but is less commonly associated with systemic tacrolimus or with topical calcineruin inhibitors. In this report, we describe the first case, to our knowledge, of trichomegaly due to long-term use of topical tacrolimus for periocular vitiligo.

Lower eyelid tension balance reconstruction: A new procedure for the repair of congenital epiblepharon with epicanthus.

BACKGROUND: Congenital epiblepharon with epicanthus (CEE) is a common eyelid malposition in Asian children, which generally involves the lower eyelid. The induced cilial entropion may cause constant ocular irritation that requires surgical repair. The purpose of this study is to report the outcomes and surgical details of a novel procedure, lower eyelid tension balance reconstruction (LETBR), for the correction of CEE. METHODS: Patients diagnosed with CEE underwent LETBR, which consists of modified half Z epicanthoplasty, and fixation between marginal orbicularis oculi muscle and lower eyelid retractor was reviewed retrospectively. The outcomes were classified as 'good' with no cilia-ocular surface contact, 'fair' with 5 or fewer asymptomatic cilia-ocular surface points of contact and 'poor' with most of the eyelashes remaining in contact with the eyeball. The surgical outcomes (good, fair or poor), recurrence and complications were evaluated. RESULTS: One hundred and forty-nine eyelids of 78 patients (43 females and 35 males; mean age 6.6 ±â€¯2.4 years, range 4-17 years) were evaluated in this study. The mean follow-up time was 14 months (range 9-24 months). At the last follow-up time, 144 of 149 eyelids were judged as 'good' (96.6%), the other 5 eyelids were judged as 'fair' (3.4%) and no eyelid was assessed with a 'poor' outcome. There were no significant complications or complaints about scarring on eyelids from patients or their parents. CONCLUSION: LETBR is effective, safe and stable for patients with CEE.

A new perspective in oculoplastic surgical management of symptomatic distichiasis in lymphedema-distichiasis syndrome.

Lymphedema-distichiasis syndrome (LDS) is an autosomal dominant condition associated with FOXC2 mutations. Patients with distichiasis are mostly symptomatic, and efforts to deal with their ocular complaints comprise of electrolysis, cryotherapy and a variety of surgical techniques. We describe an enhanced surgical technique for a case of symptomatic distichiasis of the right eye with scarred, irregular eyelid margins secondary to initial cryotherapy, whereby the distorted tarsus was excised to remove the aberrant hair follicles, the levator palpebrae superioris was released to extend the upper lid and prevent lagophthalmos and a mucous membrane graft was used to cover the exposed portion of the tarsal plate. At 14 months follow up, the lid cosmesis and position remained satisfactory, with no infection or rejection of the mucous membrane graft. Therefore, this surgical technique provides a sound option for symptomatic distichiasis, where cryotherapy can cause lid irregularity and keratinization.