facial asymmetry

Elsahy-Waters Syndrome

Clinical Characteristics
Ocular Features: 

Structural anomalies of periocular tissues are common.  Hypertelorism, proptosis, and telecanthus may be striking.  Colobomas or clefts of the upper lid are frequently seen.  The eyebrows are bushy and synophyrs may be present across a broad nasal bridge.  Megalocornea, downslanting lid fissures, glaucoma and cataracts have also been reported but are uncommon.

Systemic Features: 

The skull has been described as brachycephalic.  The midface is flat due to maxillary hypoplasia. The lower jaw is prominent and some patients have mandibular prognathism.  A bifid uvula or partial clefting of the palate are common.  Low-set and posteriorly rotated ears have been reported as well.

 Both pectus excavatum and pectus carinatum have been described.  The teeth have dysplastic enamel and often have obliterated pulp chambers and dental cysts.  Their roots may be shortened and deformed and they are often lost early.  Vertebrae may have fusion of the spines, particularly in the cervical area.  A mixed type of hearing loss is common and some degree of intellectual disability is often evident, especially in older individuals.  Most males have some degree of hypospadias.  Cryptorchidism has been reported in one individual.

Brain imaging in one case revealed no abnormalities.

Genetics

This disorder results from biallelic mutations in the CDH11 gene (16q21).  The parents have been consanguineous in most reports and no vertical transmission has been documented making autosomal recessive the most likely pattern of inheritance.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment for the general disorder has been reported.  Eyelid and palatal defects may be surgically repaired and assistive hearing devices may be of benefit.  Special education is also likely to be helpful.

References
Article Title: 

Gabriele-de Vries Syndrome

Clinical Characteristics
Ocular Features: 

A number of nondiagnostic signs occur in the periocular structures as part of the general facial dysmorphism.  There is a general fullness to the periocular area, most evident in the upper eyelids.  The lid fissures slant downward and the eyebrows are sparse.  Strabismus is often present.  Ptosis has been noted in a few individuals.

Systemic Features: 

Systemic signs are inconsistent and highly variable.  Intrauterine growth is usually below average.  Feeding problems are evident from birth.  The facial dysmorphology is highlighted by a high, broad forehead and accentuated by micrognathia and midface hypoplasia.  The ears are posteriorly rotated.  General development is delayed and milestones, if achieved, are delayed.  Behavioral problems can be manifest as anxiety and some individuals have features of the autism spectrum.  Abnormal movements such as tremor and dystonia are sometimes present.

Brain imaging may reveal delayed myelination, frontal gliosis, white matter abnormalities, and enlarged ventricles.

Genetics

Heterozygous mutations in the YY1 gene (14q32) have been identified in this condition.  The gene is a transcription factor that acts both as a repressor and an activator in specific circumstances.  Virtually all cases occur de novo.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No effective generalized treatment has been reported.

References
Article Title: 

YY1 Haploinsufficiency Causes an Intellectual Disability Syndrome Featuring Transcriptional and Chromatin Dysfunction

Gabriele M, Vulto-van Silfhout AT, Germain PL, Vitriolo A, Kumar R, Douglas E, Haan E, Kosaki K, Takenouchi T, Rauch A, Steindl K, Frengen E, Misceo D, Pedurupillay CRJ, Stromme P, Rosenfeld JA, Shao Y, Craigen WJ, Schaaf CP, Rodriguez-Buritica D, Farach L, Friedman J, Thulin P, McLean SD, Nugent KM, Morton J, Nicholl J, Andrieux J, Stray-Pedersen A, Chambon P, Patrier S, Lynch SA, Kjaergaard S, Torring PM, Brasch-Andersen C, Ronan A, van Haeringen A, Anderson PJ, Powis Z, Brunner HG, Pfundt R, Schuurs-Hoeijmakers JHM, van Bon BWM, Lelieveld S, Gilissen C, Nillesen WM, Vissers LELM, Gecz J, Koolen DA, Testa G, de Vries BBA. YY1 Haploinsufficiency Causes an Intellectual Disability Syndrome Featuring Transcriptional and Chromatin Dysfunction. Am J Hum Genet. 2017 Jun 1;100(6):907-925.

PubMed ID: 
28575647

ZTTK Syndrome

Clinical Characteristics
Ocular Features: 

The eyes are deep-set and the palpebral fissures slant downward.  Optic atrophy is often present.  The majority of individuals have poor visual responses which may also be attributed to central or cortical impairment.  Strabismus and nystagmus are frequently present.

Systemic Features: 

ZTTK syndrome is multisystem malformation and developmental disorder with a heterogeneous clinical presentation.  The facial features might suggest the diagnosis at birth but most of the signs are nonspecific including frontal bossing, underdevelopment of the midface, facial asymmetry, low-set ears, broad and/or depressed nasal bridge, and a short philtrum.  Poor feeding and hypotonia in the neonatal period are usually present and physical growth is subnormal resulting in short stature.

Brain imaging may show abnormal gyral patterns, ventriculomegaly, hypoplasia of the corpus callosum, cerebellar hypoplasia, arachnoid cysts, and loss of periventricular white matter.  About half of patients develop seizures and many have intellectual disabilities.  Spinal anomalies include hemivertebrae with scoliosis and/or kyphosis.  Other skeletal features include joint laxity in some patients and contractures in others.  Arachnodactyly, craniosynostosis, and rib anomalies have been reported.  There may be malformations in the GI, GU, and cardiac systems while immune and coagulation abnormalities have also been reported.

Genetics

Heterozygous mutations in the SON gene (21q22.11) have been identified in patients with this condition.  They may cause truncation of the gene product with haploinsufficiency or, in other patients, a frameshift in the reading.  The SON gene is a master RNA splicing regulator that impacts neurodevelopment.

Virtually all cases are the result of de novo mutations.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No effective treatment has been reported.  Physical therapy and assistive devices may be helpful.

References
Article Title: 

De Novo Truncating Variants in SON Cause Intellectual Disability, Congenital Malformations, and Failure to Thrive

Tokita MJ, Braxton AA, Shao Y, Lewis AM, Vincent M, Kury S, Besnard T, Isidor B, Latypova X, Bezieau S, Liu P, Motter CS, Melver CW, Robin NH, Infante EM, McGuire M, El-Gharbawy A, Littlejohn RO, McLean SD, Bi W, Bacino CA, Lalani SR, Scott DA, Eng CM, Yang Y, Schaaf CP, Walkiewicz MA. De Novo Truncating Variants in SON Cause Intellectual Disability, Congenital Malformations, and Failure to Thrive. Am J Hum Genet. 2016 Sep 1;99(3):720-7.

PubMed ID: 
27545676

De Novo Mutations in SON Disrupt RNA Splicing of Genes Essential for Brain Development and Metabolism, Causing an Intellectual-Disability Syndrome

Kim JH, Shinde DN, Reijnders MR, Hauser NS, Belmonte RL, Wilson GR, Bosch DG, Bubulya PA, Shashi V, Petrovski S, Stone JK, Park EY, Veltman JA, Sinnema M, Stumpel CT, Draaisma JM, Nicolai J; University of Washington Center for Mendelian Genomics, Yntema HG, Lindstrom K, de Vries BB, Jewett T, Santoro SL, Vogt J; Deciphering Developmental Disorders Study, Bachman KK, Seeley AH, Krokosky A, Turner C, Rohena L, Hempel M, Kortum F, Lessel D, Neu A, Strom TM, Wieczorek D, Bramswig N, Laccone FA, Behunova J, Rehder H, Gordon CT, Rio M, Romana S, Tang S, El-Khechen D, Cho MT, McWalter K, Douglas G, Baskin B, Begtrup A, Funari T, Schoch K, Stegmann AP, Stevens SJ, Zhang DE, Traver D, Yao X, MacArthur DG, Brunner HG, Mancini GM, Myers RM, Owen LB, Lim ST, Stachura DL, Vissers LE, Ahn EY. De Novo Mutations in SON Disrupt RNA Splicing of Genes Essential for Brain Development and Metabolism, Causing an Intellectual-Disability Syndrome. Am J Hum Genet. 2016 Sep 1;99(3):711-9.

PubMed ID: 
27545680

Mandibulofacial Dysostosis with Alopecia

Clinical Characteristics
Ocular Features: 

The extensive dysplasia of the facial bones involves those of the orbital rims and zygomatic arches.  The orbital rims can be malformed and there is often a broad depression at the inferolateral region of the eyes.  Hypoplasia or even aplasia of the eyelids maybe present and some individuals have colobomas of the lower eyelids.  The lacrimal punctae may be temporally displaced.  The eyebrows and eyelashes are often sparse as part of the generalized alopecia.

Systemic Features: 

This is a disorder of craniofacial development resulting in extensive malformations of facial bones and skin.  Different rates of development among these structures leads to facial asymmetry in many patients. Maxillary, zygomatic arch, and mandibular bones are dysplastic resulting in micrognathia and a flat midface.   The temporomandibular joints are absent and the external ear canals are often incompletely formed.  Conductive hearing loss is common with hypoplastic ossicular chains while the pinnae are low-set, crumpled and abnormally cupped.  There may be preauricular tags or pits present.  Tooth eruption is often delayed and there may be agenesis of many permanent teeth.  The maxillary sinuses may be absent.  Cleft palate is often present.

Genetics

Heterozygous mutations in the EDNRA gene (4q31) are responsible for this condition.  No familial cases have been reported and it can be assumed that the mutations arise de novo. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment for the overall condition but individual anomalies such as the colobomas, dental deformities and cleft palate may be surgically repaired.  Upper airway obstruction may require tracheostomy in infants.

References
Article Title: 

Mutations in the endothelin receptor type A cause mandibulofacial dysostosis with alopecia

Gordon CT, Weaver KN, Zechi-Ceide RM, Madsen EC, Tavares AL, Oufadem M, Kurihara Y, Adameyko I, Picard A, Breton S, Pierrot S, Biosse-Duplan M, Voisin N, Masson C, Bole-Feysot C, Nitschke P, Delrue MA, Lacombe D, Guion-Almeida ML, Moura PP, Garib DG, Munnich A, Ernfors P, Hufnagel RB, Hopkin RJ, Kurihara H, Saal HM, Weaver DD, Katsanis N, Lyonnet S, Golzio C, Clouthier DE, Amiel J. Mutations in the endothelin receptor type A cause mandibulofacial dysostosis with alopecia. Am J Hum Genet. 2015 Apr 2;96(4):519-31.

PubMed ID: 
25772936
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