telecanthus

Craniofacial-Deafness-Hand Syndrome

Clinical Characteristics

Ocular Features

This rare syndrome has anomalies in periocular structures but not in the eye itself.  The lid fissures are downward slanting with telecanthus and hypertelorism.  The nasolacrimal duct was missing in several individuals.

Systemic Features

The midface is generally flat with underdeveloped maxillary bones and absent or small nasal bones but there may be frontal bossing.  The nose appears hypoplastic with a broad, flat root resulting in dystopia canthorum.  Micrognathia and a high arched palate are sometimes present.   The sinuses are often underdeveloped.  There may be ulnar deviation of the hands and fingers while flexion contractures and clinodactyly of the 5th finger are often present.  A sensorineural hearing loss is present in many individuals.  No poliosis has been reported.

Genetics

This is an autosomal dominant condition secondary to mutations in the PAX3 gene (22q36.1) in at least some patients.  Changes in the same gene are responsible for types 1 and 3 of the Waardenburg syndrome (193500, 148820).  In fact, the major mutation, a heterozygous C-to-G transversion, has been identified in the same codon in both CDHS and Waardenburg 3 (148820) patients.

More patients need to be genotyped to clarify the clinical features distinctive of Waardenburg types 1 and 3 (193500, 148820) and CDHS syndrome.  Should we consider these conditions allelic or simply the result of variable expressivity?  The nasal root appearance is similar and both conditions are associated with sensorineural hearing loss.  Type 3 Waardenburg syndrome (148820) often has a cleft palate and musculoskeletal deformities of the upper limbs and fingers.  So far, no pigmentation changes have been reported in CDHS.

Treatment Options

Surgical release of contractures could be considered.

References

Gad A, Laurino M, Maravilla KR, Matsushita M, Raskind WH. Sensorineural deafness, distinctive facial features, and abnormal cranial bones: a new variant of Waardenburg syndrome? Am J Med Genet A. 2008 Jul 15;146A(14):1880-5.

PubMed ID: 
18553554

Asher JH Jr, Sommer A, Morell R, Friedman TB. Missense mutation in the paired domain of PAX3 causes craniofacial-deafness-hand syndrome. Hum Mutat. 1996;7(1):30-5.

PubMed ID: 
8664898

Microcornea, Myopia, Telecanthus and Posteriorly-Rotated Ears

Clinical Characteristics

Ocular Features

Small corneas measuring 9.8 – 10.5 mm are characteristic.  Acuity is usually 20/60 or better in older children but even younger children maintain steady fixation.  Refractive errors of -6 to -12.75 diopters are usually present but may be much less in other children.  Axial lengths range from 22.42 to 26.84 mm corresponding to the amount of myopia.  The degree of myopic chorioretinal change correlates roughly with the amount of axial myopia.  Telecanthus is present in all individuals.  

Systemic Features

The ears are rotated posteriorly.

Genetics

Five males with this syndrome occurred in four consanquineous/endogamous Saudi families suggesting autosomal recessive inheritance.  Homozygous mutations in ADAMTS18 (16q23.1) have been found in these four families.  However, one child had a similarly affected father suggesting to some that this may be a pseudodominant disorder.

Mutations in the same gene are responsible for Knobloch syndrome 2 (KNO2) (608454).

Treatment Options

No treatment has been reported although correction of the refractive error should be made in early childhood.  It would seem prudent to monitor the vitreoretinal system for further degeneration.

References

Aldahmesh MA, Alshammari MJ, Khan AO, Mohamed JY, Alhabib F, Alkuraya FS. The syndrome of Microcornea, Myopic Chorioretinal Atrophy and Telecanthus (MMCAT) Is Caused by Mutations in ADAMTS18. Hum Mutat. 2013 Jul 1.  PubMed PMID: 23818446.

PubMed ID: 
23818446

Khan AO. Microcornea with myopic chorioretinal atrophy, telecanthus and posteriorly-rotated ears: a distinct clinical syndrome. Ophthalmic Genet. 2012 Jun 11. [Epub ahead of print]

PubMed ID: 
22686506

Waardenburg Syndrome, Type 1

Clinical Characteristics

Ocular Features

Waardenburg syndrome is a disorder of pigmentation, sensorineural deafness, and a characteristic facial (nasal root) morphology.  Some have neural tube defects.  Based on clinical criteria, the syndrome has been divided into types 1, 2, 3, and 4, with subtypes of 2 and 4.  Types 1 and 3 are caused by mutations in the same gene.

Patients often have a white forelock and iris heterochromia.  The latter may be partial in individual irides, or the entire iris in one eye with the fundus hypopigmentation often matching the iris pattern.  The fundus may also have segmental areas of pigmentary changes corresponding to the iris heterochromia. The hypopigmented portion of the iris is often a brilliant blue.  Dystopia canthorum is a prominent and nearly constant (>95%) feature of type 1, and together with the prominent nasal root and increased intercanthal distance may suggest hypertelorism.  Synophrys is often present and the medial portions of the eyebrows can be exceptionally bushy.  Sometimes the poliosis involves the lashes and eyebrows.

Systemic Features

Congenital sensorineural deafness is an important feature.  Individuals with type 1 often have a white forelock (29%), premature graying (44%), and hypopigmented skin patches (55%).  A few patients have cleft palate and/or lip. Neural tube defects have also been reported. The considerably more rare type 3 is caused by mutations in the same gene as type 1, but it is claimed by some to be a separate disorder because of the association of limb anomalies. 

Genetics

Autosomal dominant inheritance is typical for the Waardenburg syndrome.  Types 1 and 3 are caused by mutations in the PAX3 gene (2q35) and, of these, type 1 is far more common.  Type 1 is caused by a heterozygous mutation whereas type 3 may result from either a heterozygous, compound heterozygous, or homozygous mutation.  Both types have been reported to occur in the same pedigree.  The molecular role of PAX3 in this disorder is unclear.  Paternal age plays a role in new mutations which probably account for many sporadic cases.

Waardenburg syndrome is an excellant example of genetic heterogeneity as types 1 (193500), 2 (193510), 3 (148820  and 4 (277580) can all result from mutations in different genes.  In addition, types 2 and 4 are each caused by mutations in several different genes. 

A child has been reported who was doubly heterozygous for mutations involving both MITF and PAX3. Hypopigmentation in the scalp hair, eyebrows and eyelashes was more severe than usually seen in patients with single mutations. In addition the face showed marked patchy pigmentation. One parent contributed the MITF mutation and the other added the mutation in PAX3.

 

Treatment Options

No ocular treatment is necessary.  Patients may benefit from cochlear implants.

References

Yang T, Li X, Huang Q, Li L, Chai Y, Sun L, Wang X, Zhu Y, Wang Z, Huang Z, Li Y, Wu H. Double heterozygous mutations of MITF and PAX3 result in Waardenburg Syndrome with increased penetrance in pigmentary defects. Clin Genet. 2012 Feb 9. doi: 10.1111/j.1399-0004.2012.01853.x. [Epub ahead of print]

PubMed ID: 
22320238

Wollnik B, Tukel T, Uyguner O, Ghanbari A, Kayserili H, Emiroglu M, Yuksel-Apak M. Homozygous and heterozygous inheritance of PAX3 mutations causes different types of Waardenburg syndrome. Am J Med Genet A. 2003 Sep 15;122A(1):42-5.

PubMed ID: 
12949970

Pardono E, van Bever Y, van den Ende J, Havrenne PC, Iughetti P, Maestrelli SR, Costa F O, Richieri-Costa A, Frota-Pessoa O, Otto PA. Waardenburg syndrome: clinical differentiation between types I and II. Am J Med Genet A. 2003 Mar 15;117A(3):223-35.

PubMed ID: 
12599185

Goldberg MF. Waardenburg's syndrome with fundus and other anomalies. Arch Ophthalmol. 1966 Dec;76(6):797-810.

PubMed ID: 
4958935

Pingault V, Ente D, Dastot-Le Moal F, Goossens M, Marlin S, Bondurand N. Review and update of mutations causing Waardenburg syndrome. Hum Mutat. 2010 Apr;31(4):391-406. Review.

PubMed ID: 
20127975

Donnai-Barrow Syndrome

Clinical Characteristics

Ocular Features

A number of ocular features have been described in this disorder, including telecanthus, hypertelorism, and iris hypoplasia.  Patients may have marked iris transillumination.  Myopia is commonly present and retinal detachments are a risk.  Several patients had iris colobomas.  Cataracts, small optic nerves, and macular hypoplasia have been reported as well.  The lid fissures usually slant downward. 

Systemic Features

The facial dysmorphology, in addition to the periocular malformations, includes a prominent brow or frontal bossing, posterior rotation of the ears, a flat nasal bridge and a short nose.  Sensorineural hearing loss is universal and at least some patients have complete or partial agenesis of the corpus callosum, and an enlarged anterior fontanel.  Diaphragmatic and umbilical hernias often occur together.  Low-molecular-weight proteinuria in the absence of aminoaciduria is a frequent feature.  Developmental delays are often seen but occasional patients have normal intellect.  Rare patients have seizures. 

Genetics

This is a rare autosomal recessive disorder caused by homozygous mutations in the LRP2 (low-density lipoprotein receptor-related protein 2 or megalin) gene located at 2q24-q31.  Some patients have an ocular phenotype resembling the Stickler syndrome.

Treatment Options

Treatment is focused on specific manifestations such as cataract and retinal detachment surgery. Patients need to be monitored throughout life for retinal disease.  Omphaloceles and diaphragmatic hernias need to be repaired.  Hearing aids may be beneficial. 

References

Schrauwen I, Sommen M, Claes C, Pinner J, Flaherty M, Collins F, Van Camp G. Broadening the phenotype of LRP2 mutations: a new mutation in LRP2 causes a predominantly ocular phenotype suggestive of Stickler syndrome. Clin Genet. 2013 Aug 29. [Epub ahead of print] PubMed PMID: 23992033.

PubMed ID: 
23992033

Pober BR, Longoni M, Noonan KM. A review of Donnai-Barrow and facio-oculo-acoustico-renal (DB/FOAR) syndrome: clinical features and differential diagnosis. Birth Defects Res A Clin Mol Teratol. 2009 Jan;85(1):76-81. Review.

PubMed ID: 
19089858

Patel N, Hejkal T, Katz A, Margalit E. Ocular manifestations of Donnai-Barrow syndrome. J Child Neurol. 2007 Apr;22(4):462-4.

PubMed ID: 
17624530

Chassaing N, Lacombe D, Carles D, Calvas P, Saura R, Bieth E. Donnai-Barrow syndrome: four additional patients. Am J Med Genet A. 2003 Sep 1;121A(3):258-62. Review.

PubMed ID: 
12923867

Schowalter DB, Pagon RA, Kalina RE, McDonald R. Facio-oculo-acoustico-renal (FOAR) syndrome: case report and review. Am J Med Genet. 1997 Mar 3;69(1):45-9; discussion 44. Review.

PubMed ID: 
9066882

Oculodentodigital Dysplasia

Clinical Characteristics

Ocular Features

The eyes have been reported as small and sometimes appear deep-set.  The epicanthal folds are prominent and the lid fissures are small.  Microcornea and evidence of anterior chamber dysplasia including posterior synechiae, anterior displacement of Schwalbe’s line, and stromal hypoplasia in the peripupillary area may be present.  Many eyes have some persistence of the pupillary membrane. Nystagmus and strabismus has been seen in some individuals.  A few patients have evidence of a persistent hyperplastic primary vitreous, even bilaterally. Cataracts may be present as well and a few patients have been reported with open angle glaucoma.  Most patients have normal or near normal visual acuity.

Systemic Features

The clinical features of this syndrome are highly variable.  Hair is sparse and the nails are usually dysplastic.  The nose appears small and peaked with underdevelopment of the nasal alae, and the mandible may be broad.  The cranial bones are often hyperostotic and the long bones as well as the ribs and clavicle are widened.  The middle phalanges of the digits are usually hypoplastic or may be absent.  Syndactyly of fingers and toes is often a feature and camptodactyly is common.  The teeth are small and carious with evidence of enamel dysplasia.   Hair often grows slowly and is sparse.  A variety of neurological deficits have been reported but no consistent pattern has been recognized.  However, white matter lesions and basal ganglia changes have been documented on MRI.

Genetics

Both autosomal recessive and autosomal dominant inheritance have been proposed but in both cases the mutations are in the same gene, GJA1, located at 6q21-q23.2.

This disorder is allelic to Hallermann-Streiff syndrome (234100).

Treatment Options

No treatment for the general condition is available.  Cataracts and glaucoma require attention when present, of course.

References

Musa FU, Ratajczak P, Sahu J, Pentlicky S, Fryer A, Richard G, Willoughby CE. Ocular manifestations in oculodentodigital dysplasia resulting from a heterozygous missense mutation (L113P) in GJA1 (connexin 43). Eye (Lond). 2009 Mar;23(3):549-55.

PubMed ID: 
18425059

Loddenkemper T, Grote K, Evers S, Oelerich M, Stögbauer F. Neurological manifestations of the oculodentodigital dysplasia syndrome. J Neurol. 2002 May;249(5):584-95.

PubMed ID: 
12021949

Traboulsi EI, Faris BM, Der Kaloustian VM. Persistent hyperplastic primary vitreous and recessive oculo-dento-osseous dysplasia. Am J Med Genet. 1986 May;24(1):95-100.

PubMed ID: 
3085500
PubMed ID: 

Potter Disease, Type I

Clinical Characteristics

Ocular Features

As part of the facial morphology said to be characteristic of Potter disease, there is usually hypertelorism, telecanthus and epicanthal folds.  Cataracts and angiomas of the optic disc area have also been described.

Systemic Features

Polycystic kidney disease and hepatic system anomalies are major features of Potter disease.   Pulmonary hypoplasia with neonatal respiratory distress, however, is often the most immediate cause of death in most infants.  Antenatal oligohydramnios and low birth weight are commonly present.  As many as 33% of fetuses die in utero, often the result of bilateral renal agenesis.  Infants that survive can have chronic lung disease and renal dysfunction.  Congenital heart malformations are common, including septal defects, tetralogy of Fallot and patent ductus arteriosis.  Vertebrae may have a ‘butterfly’ shape but other skeletal findings include hemivertebrae and sacral agenesis.  The neck has been described as short and the skull is brachycephalic.

The facial appearance, known as Potter facies, is said to be characteristic and may be helpful in distinguishing this type of polycystic kidney disease.  In addition to the ocular findings, the nares are often anteverted, and the external ears are large and often posteriorly rotated.

Genetics

The uniqueness of this syndrome remains to be established.  There are several polycystic kidney disorders which have a monogenic basis. These often have overlapping renal features with the condition described here but lack the facial features said to be characteristic of Potter type I disease.  Autosomal recessive inheritance has been suggested on the basis of several reported families with affected sibs from consanguineous parents but so far no gene locus or mutation has been identified.

Treatment Options

There is no treatment for the condition but symptoms of respiratory distress and renal failure may need to be addressed acutely.  Long-term therapy for pulmonary disease and renal dysfunction can be considered for older individuals.  Many infants die in the neonatal period.

References

Gillessen-Kaesbach G, Meinecke P, Garrett C, Padberg BC, Rehder H, Passarge E. New autosomal recessive lethal disorder with polycystic kidneys type Potter I, characteristic face, microcephaly, brachymelia, and congenital heart defects. Am J Med Genet. 1993 Feb 15;45(4):511-8.

PubMed ID: 
8465860

Hallermann C, Mücher G, Kohlschmidt N, Wellek B, Schumacher R, Bahlmann F, Shahidi-Asl P, Theile U, Rudnik-Schöneborn S, Müntefering H, Zerres K. Syndrome of autosomal recessive polycystic kidneys with skeletal and facial anomalies is not linked to the ARPKD gene locus on chromosome 6p. Am J Med Genet. 2000 Jan 17;90(2):115-9. Review.

PubMed ID: 
10607948

Carpenter Syndrome

Clinical Characteristics

Ocular Features

A variety of ocular anomalies have been reported in Carpenter syndrome with none being constant or characteristic.  The inner canthi are often spaced widely apart and many have epicanthal folds and a flat nasal bridge.  Other reported abnormalities are nystagmus, foveal hypoplasia, corneal malformations including microcornea, corneal opacity, and mild optic atrophy and features of pseudopapilledema.

Systemic Features

Premature synostosis involves numerous cranial sutures with the sagittal suture commonly involved causing acrocephaly (tower skull).  Asymmetry of the skull and a ‘cloverleaf’ deformity are often present.  The polydactyly is preaxial and some degree of syndactyly is common especially in the toes.  The digits are often short and may be missing phalanges.  Some patients are short in stature.  Structural brain defects may be widespread including atrophy of the cortex and cerebellar vermis.  Septal defects in the heart are found in about one-third of patients.  The ears can be low-set and preauricular pits may be seen.  Some but not all patients have obesity and a degree of mental retardation.

Genetics

This is an autosomal recessive syndrome caused by a mutation in the RAB23 gene (6p12.1-q12).

Treatment Options

No treatment of the ocular defects is necessary in most cases. Craniectomy may be required in cases with severe synostosis.

References

Hidestrand P, Vasconez H, Cottrill C. Carpenter syndrome. J Craniofac Surg. 2009 Jan;20(1):254-6.

PubMed ID: 
19165041

Jenkins D, Seelow D, Jehee FS, Perlyn CA, Alonso LG, Bueno DF, Donnai D, Josifova D, Mathijssen IM, Morton JE, Orstavik KH, Sweeney E, Wall SA, Marsh JL, Nurnberg P, Passos-Bueno MR, Wilkie AO. RAB23 mutations in Carpenter syndrome imply an unexpected role for hedgehog signaling in cranial-suture development and obesity. Am J Hum Genet. 2007 Jun;80(6):1162-70. Erratum in: Am J Hum Genet. 2007 Nov;81(5):1114. Josifiova, Dragana [corrected to Josifova, Dragana].

PubMed ID: 
17503333

Temtamy SA. Carpenter's syndrome: acrocephalopolysyndactyly. An autosomal recessive syndrome. J Pediatr. 1966 Jul;69(1):111-20.

PubMed ID: 
5935752

Axenfeld-Rieger Syndrome, Type 1

Clinical Characteristics

Ocular Features

Axenfeld-Rieger syndrome consists of a heterogeneous group of disorders with overlapping features.  Type 1 is described here. Common to all three types are the presence of ocular, dental, facial, skeletal abnormalities and autosomal dominant inheritance.  Anterior chamber dysgenesis of some form is universally present and severe glaucoma occurs in 50% of patients.  This may have its onset in childhood with typical symptoms of congenital glaucoma such as photophobia, excessive tearing and corneal clouding.  Hypoplasia of the iris is common and when progressive may result in an ectopic pupil and/or pseudopolycoria.  Iris insertion and Schwalbe’s line are often anteriorly displaced with iridocorneal adhesions, a pattern that leads to the inclusion of this disorder among those with iridogoniodysgenesis or anterior chamber dysgenesis.  Pupillary ectropion of the posterior pigmented layer of the iris may be seen.

There is considerable clinical overlap among conditions with iris dysgenesis.  Some patients with typical systemic features of Axenfeld-Rieger syndrome may even have typical anterior chamber features of Axenfeld-Rieger anomaly in one eye and severe iris hypoplasia resembling aniridia in the other.

Systemic Features

Dental anomalies and mid-facial hypoplasia secondary to underdeveloped maxillary sinuses are among the most common systemic features in type 1.  The nasal root often appears abnormally broad and the lower lip appears to protrude. The teeth are frequently small and conical in shape with wide spaces between them (diastema).  Some teeth may be missing.  The umbilicus may fail to involute normally and retains excessive, redundant skin that sometimes leads to the erroneous diagnosis of an umbilical hernia for which unnecessary surgery may be performed.  Hypospadius is frequently present while cardiac defects, sensorineural deafness, and anal stenosis are less common.

Genetics

There is clinical and genetic heterogeneity in this syndrome and precise classification of many families remains elusive without knowing the genotype.  Mutations in at least three genes are responsible and all are are responsible for phenotypes transmitted in autosomal dominant patterns.  Type 1 discussed here is caused by a mutation in the homeobox transcription factor gene, PITX2, located at 4q25-q26.  A type of iris hypoplasia (IH)/iridogoniodysgenesis (IGDS) (IRID2; 137600) disorder has been classified separately but is caused by a mutation in PITX2 as well and many cases have the same systemic features.  Mutations in the same gene have also been found in ring dermoid of the cornea (180550) and in some cases of Peters anomaly (604229).

RIEG2 (601499) is rare but a deletion of 13q14 has been reported in several cases.  Mapping in a large family with 11 affected individuals yielded a locus in the same region.  Clinical signs overlap types 1 and 3 with dental, craniofacial, and ocular features, but with hearing impairment and rare umbilical anomalies.

Mutations in the FOXC1 gene (6p25) may be responsible for RIEG3 (602482).  However, a family has been reported with a severe 'Axenfeld-Rieger phenotype' in which a digenic etiology may have been responsible: patients had mutations in both FOXC1 and PITX2

Treatment Options

The presence of glaucoma requires prompt and vigorous treatment but control is difficult with blindness too often the result.  Oral surgery may be beneficial for dental problems.  Low vision aids can be useful.

References

Weisschuh N. Digenic inheritance in axenfeld rieger syndrome. Hum Mutat. 2011 Oct;32(10):iv. doi: 10.1002/humu.21593.

PubMed ID: 
21932364

Law SK, Sami M, Piri N, Coleman AL, Caprioli J. Asymmetric phenotype of Axenfeld-Rieger anomaly and aniridia associated with a novel PITX2 mutation. Mol Vis. 2011;17:1231-8.

PubMed ID: 
21617748

Tümer Z, Bach-Holm D. Axenfeld-Rieger syndrome and spectrum of PITX2 and FOXC1 mutations. Eur J Hum Genet. 2009 Dec;17(12):1527-39.

PubMed ID: 
19513095

Sowden JC. Molecular and developmental mechanisms of anterior segment
dysgenesis.
Eye (Lond). 2007 Oct;21(10):1310-8. Review.

PubMed ID: 
17914434

Strungaru MH, Dinu I, Walter MA. Genotype-phenotype correlations in Axenfeld-Rieger malformation and glaucoma patients with FOXC1 and PITX2 mutations. Invest Ophthalmol Vis Sci. 2007 Jan;48(1):228-37.

PubMed ID: 
17197537

Alward WL. Axenfeld-Rieger syndrome in the age of molecular genetics. Am J
Ophthalmol. 2000 Jul;130(1):107-15. Review.

PubMed ID: 
11004268

Jorgenson RJ, Levin LS, Cross HE, Yoder F, Kelly TE. The Rieger syndrome. Am J Med Genet. 1978;2(3):307-18.

PubMed ID: 
263445