Lymphedema-Distichiasis Syndrome
Summary
Clinical characteristics.
Lymphedema-distichiasis syndrome (referred to as LDS in this GeneReview) is characterized by lower-limb lymphedema, and distichiasis (aberrant eyelashes ranging from a full set of extra eyelashes to a single hair). Lymphedema typically appears in late childhood or puberty, is confined to the lower limbs with or without involvement of the external genitalia, and is often asymmetric; severity varies within families. Males develop edema at an earlier age and have more problems with cellulitis than females. Distichiasis, which may be present at birth, is observed in 94% of affected individuals. About 75% of affected individuals have ocular findings including corneal irritation, recurrent conjunctivitis, and photophobia; other common findings include varicose veins and ptosis.
Diagnosis/testing.
The clinical diagnosis of LDS is established in a proband with either lymphedema and distichiasis, distichiasis and a family history of lower-limb lymphedema, or lower-limb lymphedema and a family history of distichiasis. If clinical findings are not diagnostic, the identification of a heterozygous FOXC2 pathogenic variant by molecular genetic testing confirms the diagnosis.
Management.
Treatment of manifestations: Lubrication, plucking, cryotherapy, electrolysis, or lid splitting for treatment of distichiasis; fitted compression garments and bandaging to improve swelling and discomfort associated with edema. To prevent secondary cellulitis, good skin care and prompt treatment of infected skin lesions; prompt treatment of cellulitis with antibiotics. The implementation of hosiery prior to the development of lymphedema may help reduce the extent of edema. Diuretics are not effective in the treatment of lymphedema.
Genetic counseling.
LDS is inherited in an autosomal dominant manner. Approximately 75% of affected individuals have an affected parent; about 25% have a de novo pathogenic variant. Each child of an individual with LDS has a 50% chance of inheriting the pathogenic variant. Disease severity cannot be predicted and is variable even within the same family. If the FOXC2 pathogenic variant has been identified in an affected family member, prenatal testing for a pregnancy at increased risk and preimplantation genetic testing are possible. Fetal echocardiography is recommended because of the increased risk for congenital heart disease, renal abnormalities, cleft palate, and hydrothoraces or hydrops fetalis.
Diagnosis
Suggestive Findings
Lymphedema-distichiasis syndrome (LDS) should be suspected in individuals with the following clinical findings:
- Primary lymphedema (chronic swelling of the extremities caused by an intrinsic dysfunction of the lymphatic vessels) typically affecting the lower limbs ± genitalia with onset in late childhood or puberty
- Distichiasis (aberrant, extra eyelashes arising from the meibomian glands on the inner aspects of the inferior and/or superior eyelids, ranging from a full set of extra eyelashes to a single hair
- Varicose veins in the lower limbs presenting at puberty or early adulthood
- Ptosis (drooping upper eyelid) of one or both eyes
- Other less frequent findings:
- Congenital heart disease including bicuspid aortic valves
- Cleft palate ± Pierre Robin sequence
- Renal anomalies
- Spinal extradural arachnoid cysts
- Nonimmune hydrops fetalis
- Antenatal hydrothoraces
- Neck webbing
Establishing the Diagnosis
The clinical diagnosis of LDS is established in a proband with one of the following:
- Distichiasis and lymphedema (although a young child may have no evidence of lymphedema)
- Distichiasis and a family history of lower-limb lymphedema
- Lower-limb lymphedema and a family history of distichiasis
If clinical findings are not diagnostic, the identification of a heterozygous pathogenic variant in FOXC2 by molecular genetic testing can confirm the diagnosis (see Table 1).
Molecular genetic testing approaches can include a combination of gene-targeted testing (single-gene testing, multigene panel) and comprehensive genomic testing (exome sequencing, exome array, genome sequencing) depending on the phenotype.
Gene-targeted testing requires that the clinician determine which gene(s) are likely involved, whereas genomic testing does not. Because the phenotype of LDS can be specific to this condition, individuals with the distinctive findings described in Suggestive Findings are likely to be diagnosed using gene-targeted testing (see Option 1), whereas those in whom the diagnosis of LDS has not been considered are more likely to be diagnosed using genomic testing (see Option 2).
Option 1
When the phenotypic findings suggest the diagnosis of LDS, molecular genetic testing approaches can include single-gene testing or use of a multigene panel:
- Single-gene testing. Sequence analysis of FOXC2 detects small intragenic deletions/insertions and missense, nonsense, and splice site variants; typically, exon or whole-gene deletions/duplications are not detected. Perform sequence analysis first. If no pathogenic variant is found, perform gene-targeted deletion/duplication analysis to detect intragenic deletions or duplications.
- A primary lymphedema multigene panel that includes FOXC2 and other genes of interest (see Differential Diagnosis) is most likely to identify the genetic cause of the condition at the most reasonable cost while limiting identification of variants of uncertain significance and pathogenic variants in genes that do not explain the underlying phenotype. Note: (1) The genes included in the panel and the diagnostic sensitivity of the testing used for each gene vary by laboratory and are likely to change over time. (2) Some multigene panels may include genes not associated with the condition discussed in this GeneReview. (3) In some laboratories, panel options may include a custom laboratory-designed panel and/or custom phenotype-focused exome analysis that includes genes specified by the clinician. (4) Methods used in a panel may include sequence analysis, deletion/duplication analysis, and/or other non-sequencing-based tests.For an introduction to multigene panels click here. More detailed information for clinicians ordering genetic tests can be found here.
Option 2
When the diagnosis of LDS is not considered because an individual has atypical phenotypic features, comprehensive genomic testing (which does not require the clinician to determine which gene[s] are likely involved) is the best option. Exome sequencing is the most commonly used genomic testing method; genome sequencing is also possible.
If exome sequencing is not diagnostic, exome array (when clinically available) may be considered to detect (multi)exon deletions or duplications that cannot be detected by sequence analysis.
For an introduction to comprehensive genomic testing click here. More detailed information for clinicians ordering genomic testing can be found here.
Table 1.
Molecular Genetic Testing Used in Lymphedema-Distichiasis Syndrome
| Gene 1 | Method | Proportion of Probands with a Pathogenic Variant 2 Detectable by Method |
|---|---|---|
| FOXC2 | Sequence analysis 3 | ~95% |
| Gene-targeted deletion/duplication analysis 4 | Unknown; none reported 5 |
- 1.
See Table A. Genes and Databases for chromosome locus and protein.
- 2.
See Molecular Genetics for information on allelic variants detected in this gene.
- 3.
Sequence analysis detects variants that are benign, likely benign, of uncertain significance, likely pathogenic, or pathogenic. Pathogenic variants may include small intragenic deletions/insertions and missense, nonsense, and splice site variants; typically, exon or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.
- 4.
Gene-targeted deletion/duplication analysis detects intragenic deletions or duplications. Methods used may include quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and a gene-targeted microarray designed to detect single-exon deletions or duplications.
- 5.
No data on detection rate of gene-targeted deletion/duplication analysis are available.
Clinical Characteristics
Clinical Description
Lymphedema-distichiasis syndrome (LDS) is characterized by lymphedema with onset in late childhood or puberty and is confined to the lower limbs and/or genitalia. Varicose veins are a frequent association and may develop before the onset of the lymphedema. Distichiasis, which may be present at birth, can be associated with ocular problems such as corneal irritation, recurrent conjunctivitis, and photophobia. Congenital ptosis involving one or both eyes may be present. Other less common findings include congenital heart disease, cleft palate, webbed neck, and renal anomalies. Severity varies within and between families, with some affected neonates presenting with hydrops fetalis.
Lymphedema is present in most individuals with LDS. While it typically appears in late childhood or puberty (age range: 7-40 years) [Erickson et al 2001, Brice et al 2002], congenital onset has been reported [Finegold et al 2001]. In females, pregnancy or use of oral contraceptives may precipitate the onset of swelling.
Lymphedema is confined to the lower limbs, is often asymmetric, and can be unilateral. The severity of the lymphedema varies within families. Males develop edema at a significantly earlier age and have more problems with cellulitis than females. Sixty-five percent of males in one series complained of recurrent cellulitis in the edematous leg, compared to 25% of females [Brice et al 2002].
Whereas primary lymphedema is usually associated with hypoplasia or aplasia of the lymphatic vessels, LDS is associated with an increased number of lymphatic vessels and inguinal lymph nodes [Dale 1987, Brice 2003]. The valves in the lymphatic vessels and veins are small and dysplastic, resulting in reflux and edema [Petrova et al 2004].
Isotope lymphoscintigraphy can be used to demonstrate that the swelling is caused by lymphedema. Radioactive colloid is injected into the toe web spaces and uptake in the ilioinguinal nodes is measured at intervals. Low uptake can be demonstrated in most affected individuals in association with dermal backflow, indicating lymph reflux into the lower limbs. This technique replaces lymphangiography (x-ray after injection of dye into the lymphatic vessels in the foot).
Distichiasis describes the presence of aberrant eyelashes arising from the meibomian glands on the inner aspects of the inferior and superior eyelids. These range from a full set of extra eyelashes to a single hair. Distichiasis is observed in 94% of individuals with LDS [Brice et al 2002]. Although distichiasis may be present at birth, it may not be recognized until early childhood.
About 75% of affected individuals have ocular problems related to distichiasis, including corneal irritation, recurrent conjunctivitis, and photophobia. About 25% of individuals have no symptoms from distichiasis and are thus not aware of it. Therefore, any individual with primary lymphedema of the lower limbs should be examined carefully for the presence of distichiasis.
Finegold et al [2001] described one family with a FOXC2 pathogenic variant with lymphedema only; however, only three individuals were affected and it is not known whether they were examined by slit lamp for evidence of distichiasis, which can sometimes be very subtle. In a study of 23 probands reported to have Meige disease (see Differential Diagnosis) only one had a pathogenic variant in FOXC2. More extensive examination of the individuals in this family revealed that although the proband did not have distichiasis, four affected relatives had evidence of distichiasis on slit lamp examination [Rezaie et al 2008].
In one family, distichiasis was associated with a pathogenic variant in FOXC2 but none of the affected individuals had evidence of lymphedema. The two affected individuals in the family were the 13-year-old proband (in whom lymphedema could still develop) and her father [Brooks et al 2003].
Varicose veins. The incidence of varicose veins is much higher (and onset earlier) in individuals with LDS than in the general population. About 50% of individuals with LDS have clinically evident varicose veins [Brice et al 2002]. In one family, light-reflective rheography and Doppler studies showed bilateral incompetence at the sapheno-femoral junction and long saphenous vein, which were presumed to be congenital abnormalities affecting both deep and superficial veins [Rosbotham et al 2000]. Ongoing studies of venous abnormalities suggest that they are present in all individuals with FOXC2 pathogenic variants [Mellor et al 2007]. FOXC2 is essential for lymphatic and venous valve formation in the embryo [Lyons et al 2017].
Ptosis. Approximately 30% of individuals with LDS have unilateral or bilateral congenital ptosis of variable severity.
Congenital heart disease occurs in 7%-10% of individuals with LDS. Structural abnormalities include ventricular septal defect, atrial septal defect, patent ductus arteriosis, bicuspid aortic valve, and tetralogy of Fallot. Cardiac arrhythmia, most commonly sinus bradycardia, may also occur.
Cleft palate. About 4% of individuals have cleft palate with or without Pierre Robin sequence [Papoff et al 2016].
Other findings
- Nonimmune hydrops fetalis or antenatal hydrothoraces have been reported as a rare complication of LDS. Hydrops fetalis can be caused by lymphatic abnormalities [Bellini et al 2015]. If the fetus or neonate survives, the hydrops may resolve completely. It has been suggested that the hydrops and respiratory failure may be due to severe pulmonary lymphangiectasia [de Bruyn et al 2012, Sargent et al 2014].
- Spinal extradural arachnoid cyst (SEDAC) is a cyst in the spinal canal that protrudes into the epidural space from a defect in the dura mater. Thus, SEDAC caused by a heterozygous FOXC2 loss-of-function variant should be considered a feature of LDS. It may manifest as the sole finding, but more frequently the family history is positive for SEDAC, distichiasis, and/or lymphedema [Kanaan et al 2006, Ogura et al 2013].
- Renal anomalies include hydronephrosis, ectopic kidney, and renal agenesis, which may be detected by antenatal ultrasound examination [Jones et al 2017].
Other abnormalities include scoliosis, neck webbing, uterine anomalies, strabismus, and synophrys. Neonatal chylothorax has been reported in one case in association with congenital heart disease [Chen et al 1996]. One paper suggested an association with yellow nails, but discolored nails are a common feature of chronic lymphedema regardless of cause.
Genotype-Phenotype Correlations
No genotype-phenotype correlations for the major clinical signs have been reported.
Penetrance
Approximately 80% of individuals with lymphedema-distichiasis syndrome have lymphedema by early adulthood (age 30 years), although a few individuals may develop lymphedema later.
Approximately 94% of affected individuals have distichiasis. In all families with FOXC pathogenic variants reported, at least one individual has had distichiasis.
Nomenclature
Lymphedema and ptosis, once described as a separate entity, is thought to be the same as lymphedema-distichiasis syndrome [Finegold et al 2001].
Prevalence
The prevalence of lymphedema-distichiasis syndrome is not known; it is a well-recognized and relatively frequent cause of autosomal dominant primary lymphedema.
Differential Diagnosis
Table 2.
Disorders to Consider in the Differential Diagnosis of Lymphedema-Distichiasis Syndrome (LDS)
| DiffDx Disorder | Gene(s) | MOI | Clinical Features of DiffDx Disorder | |
|---|---|---|---|---|
| Overlapping w/LDS | Distinguishing from LDS | |||
| Milroy disease | FLT4 | AD | Lymphedema 1 |
|
| Meige disease (OMIM 153200) | Unknown | AD |
| |
| Hypotrichosis-lymphedema-telangiectasia syndrome (OMIM 607823) | SOX18 | AR |
| |
| Hypotrichosis-lymphedema-telangiectasia-renal defect syndrome (OMIM 137940) | AD | |||
| Lymphedema microcephaly (OMIM 152950) | KIF11 | AD |
| |
| Yellow nail syndrome (OMIM 153300) | Unknown | AD 2 |
| |
| Emberger syndrome (OMIM 614038) | GATA2 | AD |
| |
| Blepharocheilodontic syndrome (OMIM PS119580) | CDH1 CTNND1 | AD | Distichiasis 4 |
|
AD = autosomal dominant; AR = autosomal recessive; DiffDx = differential diagnosis; ID = intellectual disability; MOI = mode of inheritance; XL = X-linked
- 1.
The presence of lymphatic vessels on lymphoscintigraphy in LDS contrasts with other causes of primary lymphedema, including Milroy disease and Meige disease, which show aplasia or hypoplasia of the lymphatic vessels.
- 2.
Inheritance is said to be autosomal dominant; most affected individuals represent simplex cases (i.e., a single occurrence in a family) [Hoque et al 2007].
- 3.
Nail changes are different from the typically discolored nails often associated with chronic lymphedema.
- 4.
Distichiasis should also be clinically distinguished from trichiasis, a more common condition in which lashes arise normally from the anterior lamella of the eyelids but are misdirected. The misdirected lashes can cause symptoms similar to distichiasis (e.g., corneal irritation and photophobia).
Management
Evaluations Following Initial Diagnosis
To establish the extent of disease and needs of in an individual diagnosed with lymphedema-distichiasis syndrome (LDS), the evaluations summarized in Table 3 (if not performed as part of the evaluation that led to the diagnosis) are recommended.
Table 3.
Recommended Evaluations Following Initial Diagnosis in Individuals with Lymphedema-Distichiasis Syndrome
| System/ Concern | Evaluation | Comment |
|---|---|---|
| Eyes | Ophthalmologic eval |
|
| Lymphedema | Physical exam of lower legs to document presence of lymphedema & any evidence of cellulitis | Isotope lymphoscintigraphy to detect lymphatic weakness before onset of swelling |
| Vascular | Physical exam of varicose veins w/young onset (adolescence / early adulthood) | Venous duplex scans |
| Cleft palate | Assess for cleft palate or Pierre Robin sequence. | |
| Cardiovascular | Assess for congenital heart defects. |
|
| Spine | Assess for spinal extradural arachnoid cyst. |
|
| Assess for scoliosis. | ||
| Renal | Renal ultrasound eval | Assess for renal anomalies. |
| Miscellaneous/ Other | Consultation w/clinical geneticist &/or genetic counselor |
Treatment of Manifestations
Eyes
- Conservative management of symptomatic distichiasis with lubrication or epilation (plucking), or more definitive management with cryotherapy, electrolysis, or lid splitting [O'Donnell & Collin 1993]. Recurrence is possible even with more definitive treatment.
- Surgery for ptosis if clinically indicated (e.g., obscured vision, cosmetic appearance)
Lymphedema. Refer to a lymphedema therapist for management of edema (fitting hosiery, massage). Although the edema cannot be cured, some improvement may be possible with the use of carefully fitted hosiery and/or bandaging, which may reduce the size of the swelling as well as the associated discomfort. The implementation of hosiery prior to the development of lymphedema may be beneficial in reducing the extent of edema [P Mortimer, personal communication].
The following are appropriate:
- Prevention of secondary cellulitis in areas with lymphedema, particularly as cellulitis may aggravate the degree of edema. Prophylactic antibiotics (e.g., penicillin V 500 mg/day) are recommended for recurrent cellulitis.
- Prompt treatment of early cellulitis with appropriate antibiotics. It may be necessary to give the first few doses intravenously if there is severe systemic upset.
- Prevention of foot infections (particularly athlete's foot / infected eczema) by treatment with appropriate creams/ointments
Note: (1) Diuretics are not effective in the treatment of lymphedema. (2) Cosmetic surgery is often associated with disappointing results.
See fact sheet for more information.
Varicose veins. Manage varicose veins conservatively with compression garments if possible, as surgery could aggravate the edema and increase the risk of infection or cellulitis.
Cardiac anomalies/arrhythmia. Manage as per standard practice.
Spine
- Spinal extradural arachnoid cyst. Refer individuals with symptomatic spinal cysts (i.e., any neurologic signs or symptoms, especially in the lower limbs) to a neurosurgeon.
- Scoliosis. Standard treatment
Renal malformations. Standard treatment
Surveillance
Table 4.
Recommended Surveillance for Individuals with Lymphedema-Distichiasis Syndrome
| System/Concern | Evaluation | Frequency |
|---|---|---|
| Eyes | Slit lamp exam of the eyes | As required for control of symptoms from distichiasis |
| Lymphedema | Lymphoscintigraphy at diagnosis, then clinical assessment | 1-2x/yr, but regular lymphedema therapy (every 6 mos) 1 |
| Varicose veins | Clinical assessment | 1-2x/yr |
| Cleft palate | Per craniofacial team | |
| Cardiovascular | Per cardiologist | |
| Spine | Investigate w/spine MRI; only if symptomatic. | |
| Renal | Per treating nephrologist/urologist |
- 1.
See fact sheet for more information.
Evaluation of Relatives at Risk
See Genetic Counseling for issues related to testing of at-risk relatives for genetic counseling purposes.
Pregnancy Management
Edema may be exacerbated during pregnancy, but often improves after delivery. The patient should continue compression and bandage treatment as long as possible but this should be adapted to the patient's needs (e.g., thigh-length compression garments instead of tights). See fact sheet for more information.
Therapies Under Investigation
Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.