digital anomalies

Duane-Radial Ray Syndrome

Clinical Characteristics
Ocular Features: 

Most individuals have features of Duane’s anomaly, sometimes unilaterally.  Optic pallor with poor vision has been described in well-studied patients who also had thinning of the retinal nerve fiber layer.  The optic disk may appear hypoplastic.  Visual evoked potentials and pattern ERG amplitudes are decreased.

Other less common ocular features are microcornea, microphthalmia, ophthalmoplegia, hypertelorism, cataracts, epicanthal folds, colobomas, and chorioretinal scars.

Systemic Features: 

The systemic features are inconsistent (variable expressivity) with most patients having some variation of hypodactyly, polydactyly, syndactyly, and malformation of the hands.  The thumb is the most common digit involved and this is often associated with thenar hypoplasia.  Other skeletal features of the radial ray syndrome including absence of the radial and ulnar bones are variably present.  Hearing loss is described as sensorineural in etiology but malformations of the pinnae and external meatus are sometimes present.

Kidney anomalies include horseshoe malformations, abnormal rotation, ectopia, small size, vesicoureteric reflux, and pelvicalyceal dilatation.

Genetics

This is an autosomal dominant disorder due to heterozygous mutations in the SALL4 gene (20q13.2).

This syndrome is sometimes confused with the Holt-Oram syndrome but the latter is the result of mutations in a different gene and lacks ocular and renal abnormalities.  Duane syndrome 1 and 2 may also occur as isolated conditions.

The considerable clinical heterogeneity has led to alternate titles for this syndrome. For example, what is sometimes called the IVIC syndrome (147750) with similar features is also caused by mutations in this gene.  Duane-radial ray syndrome has also been called Okihiro syndrome. 

 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment is symptomatic in most cases although reconstructive surgery may be helpful for severe hand deformities.  Low vision aids may be beneficial.  

References
Article Title: 

Orofaciodigital Syndrome IX

Clinical Characteristics
Ocular Features: 

Multiple forms of orofaciodigital syndrome are recognized but this one (type IX, originally reported as VIII) is of ophthalmological interest because of the retinal anomalies.  Gurrieri’s original report calls these “retinochoroideal lacunae of colobomatous origin” similar to those found in Aicardi syndrome (304050).  These were further described as hypopigmented and atrophic appearing.  Synophyrs and hypertelorism have been noted and the ears may be low-set.

Systemic Features: 

Facial, oral, digital, psychomotor delays, and skeletal anomalies are major systemic features of OFD IX.  The oral manifestations include a high arched palate, cleft lip (sometimes subtle), bifid tongue, hemartomas on the tongue, abnormal tongue frenulation, and dental anomalies (supernumerary teeth).  Digital anomalies consist of mild syndactyly and occasionally polydactyly, brachydactyly, and bifid large toes.  Some patients have short stature.  Psychomotor delay is common and some patients have been described as mentally retarded.

Genetics

This is most likely an autosomal recessive condition since multiple sibs of both sexes have been identified.  Nothing is known of the locus or specific mutation.

Gurrieri’s name is attached to another syndrome (Gurrieri syndrome [601187]) with entirely different oculoskeletal features.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Specific malformations may need correction but there is no treatment for the overall disease.

References
Article Title: 

Microphthalmia with Limb Anomalies

Clinical Characteristics
Ocular Features: 

Patients have either microphthalmia or anophthalmia which may be present unilaterally or bilaterally.  The MRI in several patients has revealed complete absence of the globes, optic nerves, chiasm, and optic tracts.  The eyelashes are often sparse with shortened palpebral fissures and broad lateral eyebrows.

Systemic Features: 

Global developmental delays, failure to thrive, and mild to moderate mental retardation are common.   Syndactyly, polydactyly, and oligodactyly with hypoplasia of the long bones are present to a variable degree.  Synostosis in the digits, ankles, and wrist is often seen.  A split hand (lobster-claw deformity) is variably present.  Other anomalies such as the kidneys (horseshoe kidney), undescended testes, anomalous venous circulation and deformed vertebrae have been reported.  The midface is often flattened.  A high palate, cleft lip, and mild scoliosis may be seen.

Genetics

This is an autosomal recessive disorder resulting from homozygous mutations in the SMOC1 gene (14q24.2) but there is some evidence of genetic heterogeneity as the disorder has been mapped to 10p11.23 in several families.  However, no causative mutations were found in this region.  Consanguinity among parents is common.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no treatment in most cases for the ocular malformations.  Some of the limb anomalies may be surgically correctable.

References
Article Title: 

SMOC1 is essential for ocular and limb development in humans and mice

Okada I, Hamanoue H, Terada K, Tohma T, Megarbane A, Chouery E, Abou-Ghoch J, Jalkh N, Cogulu O, Ozkinay F, Horie K, Takeda J, Furuichi T, Ikegawa S, Nishiyama K, Miyatake S, Nishimura A, Mizuguchi T, Niikawa N, Hirahara F, Kaname T, Yoshiura K, Tsurusaki Y, Doi H, Miyake N, Furukawa T, Matsumoto N, Saitsu H. SMOC1 is essential for ocular and limb development in humans and mice. Am J Hum Genet. 2011 Jan 7;88(1):30-41.

PubMed ID: 
21194678

A locus for ophthalmo-acromelic syndrome mapped to 10p11.23

Hamanoue H, Megarbane A, Tohma T, Nishimura A, Mizuguchi T, Saitsu H, Sakai H, Miura S, Toda T, Miyake N, Niikawa N, Yoshiura K, Hirahara F, Matsumoto N. A locus for ophthalmo-acromelic syndrome mapped to 10p11.23. Am J Med Genet A. 2009 Mar;149A(3):336-42.

PubMed ID: 
19208380

Ablepharon-Macrostomia Syndrome

Clinical Characteristics
Ocular Features: 

The clinical features of this syndrome remain to be fully delineated.  Important ocular anomalies include malformations and sometimes absence of the upper and lower eyelids.  The eyelashes and eyebrows may be sparse or even missing.  The lid fissures, if present, may be shortened.  Deformities of the eyelids can lead to corneal exposure and secondary vision loss. 

Systemic Features: 

Other facial malformations include macrostomia which may be secondary to aberrant lip fusion.  Micrognathia has been described.  The external ears are often rudimentary, sometimes described as rosebuds.  The nasal bridge is low and the nostrils anteverted.  The zygomatic arches may be absent.  The nipples are often missing as well.  Scalp hair is sparse or even absent while the skin is dry, coarse, and often has redundant folds (cutis laxa).  Mild skin syndactyly, camptodactyly, finger contractures, and shortening of metacarpals have been noted.  The genitalia are often ambiguous and some patients have had ventral hernias.  Hearing loss can be a feature.  Growth retardation has been seen but developmental delays if present are mild.  Intelligence can be normal. 

Genetics

The majority of sibships suggest autosomal recessive inheritance although autosomal dominant inheritance has been proposed for several. One male child has been reported to have a partial deletion of chromosome 18 but other complex rearrangements were also present.

An amino acid substitution (lysine) in the basic domain of the TWIST2 gene has been found in seven families in which ablepharon-macrostomia followed an autosomal dominant pattern.  Mutations in the same TWIST2 domain but leading to substitutions of glutamine or alanine amino acids is responsible for the Barber-Say phenotype (209885).

Mutations in the TWIST2 gene may also be responsible for Setleis syndrome (227260). 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Cosmetic surgery can correct at least some of the malformations. Vigorous effort may be required to maintain corneal surface wetting. 

References
Article Title: 

Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes

Marchegiani S, Davis T, Tessadori F, van Haaften G, Brancati F, Hoischen A, Huang H, Valkanas E, Pusey B, Schanze D, Venselaar H, Vulto-van Silfhout AT, Wolfe LA, Tifft CJ, Zerfas PM, Zambruno G, Kariminejad A, Sabbagh-Kermani F, Lee J, Tsokos MG, Lee CC, Ferraz V, da Silva EM, Stevens CA, Roche N, Bartsch O, Farndon P, Bermejo-Sanchez E, Brooks BP, Maduro V, Dallapiccola B, Ramos FJ, Chung HY, Le Caignec C, Martins F, Jacyk WK, Mazzanti L, Brunner HG, Bakkers J, Lin S, Malicdan MC, Boerkoel CF, Gahl WA, de Vries BB, van Haelst MM, Zenker M, Markello TC. Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes. Am J Hum Genet. 2015 Jul 2;97(1):99-110.

PubMed ID: 
26119818

Baller-Gerold Syndrome

Clinical Characteristics
Ocular Features: 

The ocular features are a rather minor part of this syndrome and are found in less than a third of patients.  These primarily involve lids and adnexae with telecanthus, downslanting lid fissures, and epicanthal folds.  Some individuals have nystagmus while strabismus, blue sclerae, and ectropion have also been reported.

Systemic Features: 

The cardinal features of this syndrome are craniosynostosis and radial defects.  However, a large number of variable defects such as imperforate or anteriorly placed anus, rectovaginal fistula, absent thumbs, polydactyly, and mental retardation may also be present.  The radius may be completely absent or abnormally formed and occasionally the ulnar bone is involved as well.  Some patients have a conductive hearing loss.

Genetics

This syndrome is caused by a mutation in the RECQL4 gene at 8q24.3 and seems to be an autosomal recessive disorder.  Its syndromal status as a unique syndrome is in some doubt because of considerable phenotypic overlap with other entities such as Roberts (268300) and Saethre-Chotzen (101400) syndromes.  The latter however is caused by a mutation in the TWIST1 gene and the former by mutations in the ESCO2 gene.

The same gene is mutated in Rothmund-Thomson syndrome (268400) suggesting allelism of the two disorders.  The phenotype is vastly different in the two disorders however.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available.

References
Article Title: 
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