syndactyly

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: 

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

Microphthalmia, Syndromic 1

Clinical Characteristics
Ocular Features: 

Microphthalmia is often a part of other ocular and systemic anomalies.  The full range of essential features of Lenz microphthalmia remains unknown but is often diagnosed in males when colobomas and microcornea are associated with mental deficits together with urogenital and skeletal anomalies.  Microphthalmos may be unilateral and ocular cysts are common.  The globes may be sufficiently small that anophthalmia is sometimes diagnosed but this is a misnomer as some ocular tissue is always present.   Sixty per cent of eyes have colobomas which are often bilateral and may involve the optic disc, choroid, ciliary body, and iris.  Blindness is common.  

Systemic Features: 

A large number of associated systemic anomalies have been reported with this type of microphthalmia.  Skeletal features include microcephaly, spinal deformities, high arched palate, pectus excavatum, absent or dysplastic clavicles (accounting for the narrow or sagging shoulders), and digital anomalies including syndactyly, duplicated thumbs and clinodactyly.  Physical growth retardation is evident by shortness of stature.   Urogenital malformations are present in 77% of individuals and include hypospadius, cryptorchidism, hydroureter, and renal dysgenesis.  Dental anomalies include oligodontia and irregular lower incisors that may be widely spaced.  Some degree of intellectual disability is present in 63%.  The ears may be abnormally shaped, low-set, rotated posteriorly, and anteverted. 

Genetics

This is a rare X-linked disorder that is apparently due to an unknown mutation at Xq27-Xq28.  No male-to-male transmission has been observed but affected males rarely reproduce as a result of various urogenital anomalies.

A somewhat similar X-linked syndrome of microphthalmia, sometimes called OFCD syndrome (syndromic 2 microphthalmia; 300166) has been reported to be caused by mutations in BCOR (Xp11.4).  This MCOPS2 disorder is often considered to be X-linked dominant with lethality in males.

Another X-linked non-syndromic form of microphthalmia with colobomas has been reported (Microphthalmia with Coloboma, X-Linked; 300345).  In addition there is a similar disorder of simple Microphthalmia with Coloboma that is inherited either in an autosomal dominant or autosomal recessive pattern (605738, 610092, 611638, 613703, 251505 ).

Pedigree: 
X-linked recessive, carrier mother
X-linked recessive, father affected
Treatment
Treatment Options: 

There is no treatment beyond supportive care for specific health issues. 

References
Article Title: 

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

EEM Syndrome

Clinical Characteristics
Ocular Features: 

Granular pigmentation and a grayish coloration of the retina may be present.  The peripheral retina usually appears normal but the posterior pole and macula have pigmentary changes consisting of clumping and geographic atrophy.  Fluorescein angiography shows patchy areas of hyperfluorescence.  Patients in their 30s have been reported to have normal ERGs in one study.  Reduced acuity can be noted in the first decade but progression is slow.  Acuity levels in the 20/200 range may be seen in the fourth decade of life. 

Systemic Features: 

Ectodermal dysplasia with ectrodactyly and syndactyly are prominent features of this syndrome.  Hypotrichosis of the scalp, eyebrows and eyelashes is often seen.  Partial anodontia and diastema are also features.  Syndactyly of the toes is present more frequently than found among the fingers. 

Genetics

This is an autosomal recessive disorder resulting from mutations in the CDH3 gene (16q22.1).

EEM syndrome is allelic to the Hypotrichosis with Macular Dystrophy syndrome (601553).  However, the latter lacks the dental, limb, and digital anomalies as well as the hypotrichosis of eyebrows and eyelashes.  

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for this disease. 

References
Article Title: 

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).

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

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

References
Article Title: 

Smith-Lemli-Opitz Syndrome

Clinical Characteristics
Ocular Features: 

A large number of ocular anomalies have been found in SLO syndrome but the most common is blepharoptosis of some degree.  No consistent pattern of ocular abnormalities has been reported.  Atrophy and hypoplasia of the optic nerve, strabismus, nystagmus, and cataracts may be present.   Abnormally low concentrations of cholesterol and cholesterol precursors have been found in all ocular tissues studied.

Systemic Features: 

This is a syndrome of multiple congenital anomalies.  Among these are dwarfism, micrognathia, hard palate anomalies, hypotonia, anomalies of the external genitalia, polysyndactyly, microcephaly, and mental retardation.  It has been suggested that many individuals have a characteristic behavioral profile consisting of cognitive delays, hyperreactivity, irritability, language deficiency, and autism spectrum behaviors.  Some individuals exhibit aspects of self destructive behavior.  Tissue levels of cholesterol are low.

Genetics

SLO syndrome is an autosomal recessive disorder resulting from mutations in the sterol delta-7-reductase  (DHCR7) gene mapped to 11q12-q13. The result is a defect in cholesterol synthesis.

The clinical features significantly overlap those seen in Meckel (249000) and Joubert (213300) syndromes.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

A high cholesterol diet has been reported to have a beneficial effect on behavior and general well-being.

References
Article Title: 

Focal Dermal Hypoplasia

Clinical Characteristics
Ocular Features: 

Features have considerable heterogeneity and few patients have all of them.  Some ocular abnormalities are found in 40% of patients.  Microphthalmia is common and many patients (30%) have colobomas of the iris and choroid.  Some patients have dislocated lenses.  Distinctive peripheral corneal lesions consisting of discrete vascularized subepithelial opacities have been described.  Occasional patients have conjunctival or lid margin papillomas.  Strabismus and nystagmus are common.

Systemic Features: 

This disorder has a wide variety of clinical features and many occur in only a few patients.  The skin has focal areas of hypoplasia with hypopigmentation, often appearing in a streak or linear pattern.  These areas may be present at birth and contain bullae or urticarial lesions with signs of inflammation.  Telangiectases and herniated fat may appear in these areas.   Oral, esophageal, and laryngeal fibrovascular papillomas occur but they may also be seen in the perineal, vulvar, and perianal areas.  These may be large, friable, and recurrent.  The teeth erupt late and are usually hypoplastic.  The nails are often dysplastic and the hands and feet may be 'split' with syndactyly of the third and fourth fingers giving a 'lobster claw' appearance.  Polydactyly may be present.  Most have thin 'protruding' ears.  A variety of skeletal anomalies have been reported including absence of metatarsals and metacarpals.  A considerable number of patients have mild to moderate mental deficits.  Severely affected females may die in infancy.

Genetics

This is considered an X-linked dominant disorder with lethality in males.  However, numerous affected males (>30) and rare instances of father-to-daughter transmission have been reported and it has been suggested that half-chromatid mutations or postzygotic somatic mosaicism in these males might be responsible.  Mutations in the PORCN gene (Xp11.23) have been associated with FDH.

Pedigree: 
X-linked dominant, mother affected
Treatment
Treatment Options: 

Surgery may be required for the papillomas if they are obstructive.

References
Article Title: 

Saethre-Chotzen Syndrome

Clinical Characteristics
Ocular Features: 

The lids are often ptotic and asymmetrically so in keeping with the skull asymmetry.  Strabismus is common.  Optic atrophy, downward slanting lid fissures, epicanthal folds, and dacryostenosis have also been reported.

Systemic Features: 

The skull is acrocephalic and asymmetrical.  The frontal hairline is low.  The external ear and especially the crus of the ear are malformed and the latter is sometimes considered a valuable diagnostic sign.  There is frequently mild soft tissue syndactyly of the third, fourth and fifth toes, and the distal phalanges of the hallux may be bifid.  Syndactyly of the fingers is sometimes present as well.  Clefting of the soft and hard palates is commonly present and a few patients have had joint contractures.  Hearing loss of all types has been reported.  Mental development seems to be normal.  An increased risk of breast cancer has been found among Swedish patients.

SCS is considered to be one of the more common types of syndromic craniosynostosis.

Genetics

Saethre-Chotzen syndrome is caused by mutations in the TWIST1 (10q26) and possibly FGFR2 genes suggesting genetic heterogeneity.  There is also a great deal of clinical heterogeneity.  This syndrome is sometimes confused with Gorlin-Chaudhry-Moss syndrome (233500).  Pedigrees are consistent with autosomal dominant inheritance.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no known treatment except for cranioplasty and repair of palate clefting.

References
Article Title: 

Gorlin-Chaudhry-Moss Syndrome

Clinical Characteristics
Ocular Features: 

Orbital hypoplasia, short, abnormally slanted (up or down) lid fissures, and sometimes lid notching (colobomas?) are characteristic facial features as are bushy eyebrows and synophrys.  Lacrimal duct stenosis has been noted.  The eyes are described as 'small' but no ophthalmological examination has been performed to document microphthalmia or other ocular anomalies.  No mention is made of visual problems.

Systemic Features: 

Premature closure of the coronal suture and midface hypoplasia lead to striking brachycephaly.  The scalp hairline is low and scalp hair is abundant and coarse.  In fact, hypertrichosis is seen throughout the body.  Hypo- and microdontia with irregularly spaced teeth and a high arched palate are common features.  Clefts of the soft palate has been observed.  The ears can be small and rotated posteriorly.  The labia majora are hypoplastic as are the distal phalanges of the fingers and toes.  Mild syndactyly of the second and third fingers and toes have been described.  The nails may be abormally small.  Conductive hearing loss may be present.  Growth and psychomotor development seem to be normal although some patients have been described to have a 'stocky' build.  The facial features tend to coarsen over time.

Genetics

Autosomal recessive inheritance has been suggested but nothing is known about the gene locus.  All 5 reported patients have been female.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is known.

References
Article Title: 

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