craniosynostosis

3MC Syndromes

Clinical Characteristics
Ocular Features: 

The major ocular features involve the periocular structures.  These result in the typical facial dysmorphism and include hypertelorism, blepharoptosis, blepharophimosis, and highly arched eyebrows. Ptosis, unilateral or bilateral, can be present.

One patient was reported to have unilateral aniridia and a corneal leucoma.  Tear duct atresia was reported in another individual.

Systemic Features: 

Systemic features are highly variable in their presence and severity.   Facial clefting, growth deficiency, cognitive impairment, and hearing loss are present about half the time in some combination while craniosynostosis, urogenital anomalies, and radioulnar synostosis are seen in about a third of individuals.  More rare features include cardiac defects and abdominal midline defects (omphalocele and diastasis recti).

Genetics

This condition (3MC) is now postulated to include at least 3 disorders (Malpuech-Michels-Mingarelli-Carnevale syndromes) and considered here as a single autosomal recessive disease complex with overlapping clinical features that requires genotyping for diagnostic separation.  These are: 3MC1 syndrome (257920) resulting from homozygous mutations in the MASP1 gene (3q27.3), 3MC2 syndrome (265050) caused by mutations in the COLEC11 gene (2p25.3) and 3MC3 (248340) with mutations in the COLEC10 gene (8q24.12).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective general treatment has been reported.

References
Article Title: 

COLEC10 is mutated in 3MC patients and regulates early craniofacial development

Munye MM, Diaz-Font A, Ocaka L, Henriksen ML, Lees M, Brady A, Jenkins D, Morton J, Hansen SW, Bacchelli C, Beales PL, Hernandez-Hernandez V. COLEC10 is mutated in 3MC patients and regulates early craniofacial development. PLoS Genet. 2017 Mar 16;13(3):e1006679. doi: 10.1371/journal.pgen.1006679. eCollection 2017 Mar.

PubMed ID: 
28301481

Mutations in lectin complement pathway genes COLEC11 and MASP1 cause 3MC syndrome

Rooryck C, Diaz-Font A, Osborn DP, Chabchoub E, Hernandez-Hernandez V, Shamseldin H, Kenny J, Waters A, Jenkins D, Kaissi AA, Leal GF, Dallapiccola B, Carnevale F, Bitner-Glindzicz M, Lees M, Hennekam R, Stanier P, Burns AJ, Peeters H, Alkuraya FS, Beales PL. Mutations in lectin complement pathway genes COLEC11 and MASP1 cause 3MC syndrome. Nat Genet. 2011 Mar;43(3):197-203.

PubMed ID: 
21258343

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

Cole-Carpenter Syndrome 2

Clinical Characteristics
Ocular Features: 

Postnatally the eyes are prominent and hypertelorism has been reported.  The palpebral fissures slant downward and the root of the nose is angular. 

Systemic Features: 

This is primarily a skeletal disorder with impaired skull ossification and multiple bone fractures of prenatal origin.  It is sometimes confused with forms of osteogenesis imperfecta.  The skull is poorly ossified and frequent diaphyseal fractures of the long bones occur leading to motor delays and short stature.  Rib fractures are sometimes seen. Intelligence seems to be normal.  A receding chin has been noted and the hard palate is highly vaulted.  The midface is flat.

Genetics

This disorder results from compound heterozygous mutations in the SEC24D gene (4q26).  Only a few patients have been reported.

For a somewhat similar but autosomal dominant disorder see Cole-Carpenter Syndrome 1 (112240).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Physical activity should be restricted to noncontact sports and where the cranium has ossification defects a helmet should be worn.  Fractures should be appropriately treated.

References
Article Title: 

Mutations in SEC24D, Encoding a Component of the COPII Machinery, Cause a Syndromic Form of Osteogenesis Imperfecta

Garbes L, Kim K, Riess A, Hoyer-Kuhn H, Beleggia F, Bevot A, Kim MJ, Huh YH, Kweon HS, Savarirayan R, Amor D, Kakadia PM, Lindig T, Kagan KO, Becker J, Boyadjiev SA, Wollnik B, Semler O, Bohlander SK, Kim J, Netzer C. Mutations in SEC24D, Encoding a Component of the COPII Machinery, Cause a Syndromic Form of Osteogenesis Imperfecta. Am J Hum Genet. 2015 Mar 5;96(3):432-9.

PubMed ID: 
25683121

Cole-Carpenter Syndrome 1

Clinical Characteristics
Ocular Features: 

The bony orbits are shallow and the eyes appear prominent as part of the facial and skull bone deformities.  The proptosis may be progressive and eventually interfere with blinking and normal surface wetting of the cornea. 

Systemic Features: 

This condition may superficially resemble osteogenesis imperfecta with osseous deformities and frequent fractures.  However, the occurrence of craniosynostosis and hydrocephalus helps to distinguish it.  Cranial sutures may be slow to fuse and macrocephaly has been described.  Communicating hydrocephalus can be a feature and may require shunting.  Some patients have osteopenia of the long bones that fracture easily.

The facial features are said to be distinctive with midface hypoplasia, low-set ears, micrognathia, and, of course, prominent globes.  Growth may be subnormal and a variety of limb bone and digital anomalies have been described.  Intelligence is normal, however.

Genetics

This condition is the result of heterozygous mutations in the P4HB gene (17q25.3) (PDI family).

See Cole-Carpenter Syndrome 2 (616294) for a somewhat similar disorder that is recessively inherited.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

A frontal craniectomy may be necessary during early childhood to relieve the proptosis particularly when blinking is impaired.  Patients must be followed for the development of communicating hydrocephalus.  Long bone fractures require prompt treatment. 

References
Article Title: 

Jackson-Weiss Syndrome

Clinical Characteristics
Ocular Features: 

The facial malformation such as the flattened midface with maxillary hypoplasia leads to shallow orbits with the result that the eyes appear proptotic.  Some but not all individuals have strabismus, usually exotropia.  Optic atrophy has not been reported. 

Systemic Features: 

Infants usually present at birth with skull deformities resembling some variant of acrocephalosyndactyly.  Some or all of the skull sutures may be fused.  In some individuals craniectomy is necessary while others have normal brain development.  Few patients have evidence of abnormal neurological development and psychometric testing reveals IQ's in the normal range.  The midface is flattened with sometimes severe maxillary hypoplasia.  No hand deformities are present. 

There may be cutaneous syndactyly of the second and third toes.  Variable tarsal fusion is often present. The great toe may be abnormally broad and deviated medially.  The first metatarsals and proximal phalanges of the great toes are generally broad.

The phenotype is highly variable and even among individuals in genetically more homogeneous populations such as the Old Order Amish the range of facial, skull, and digital anomalies include features found among all of the craniosynostosis syndromes except for Apert syndrome.

Genetics

Heterozygous mutations in the FGFR2 gene (10q26.13) are likely responsible for this autosomal dominant condition. 

Other forms of craniosynostosis in which mutations in FGFR2 have been found are: Beare-Stevenson Syndrome (123790), Crouzon Syndrome (123500), Pfeiffer Syndrome (101600), Apert Syndrome (101200), and Saethre-Chotzen Syndrome (101400).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment beyond surgical correction of selected malformations. The risk of exposure keratitis requires constant vigilance and appropriate corneal lubrication.

References
Article Title: 

Beare-Stevenson Syndrome

Clinical Characteristics
Ocular Features: 

The midface hypoplasia and shallow orbits result in the appearance of prominent eyes.  Ptosis and hypertelorism have been reported while the palpebral fissures are downslanting. One patient has been reported to have optic atrophy.  Another patient was described with cloudy corneas, irregular irides and nonreactive pupils.

Systemic Features: 

Pregnancies may be complicated by polyhydramnios.  Infants are born with craniosynostosis with a cloverleaf pattern usually.  The skull is often shortened in the anteroposterior axis with flattening of the occipital region.  The skin is deeply furrowed with the cutis gyrata patterns most prominent in the posterior scalp but also present on the palms, soles, pinnae, and elsewhere.  Acanthosis nigricans is often present.

There is midface hypoplasia and nearly all individuals have intellectual disability.

The external ear canals can be atretic, the nares are often anteverted, and the mouth may be small.  An excess number of neonatal teeth and hypoplastic nails have been noted.  Hydrocephalus is common.  The umbilical stump is often unusually prominent.  Anogenital anomalies such as an anteriorly placed anus, cryptorchidism, and bifid scrotum may be present.  Pyloric stenosis is sometimes present.

Upper airway obstruction with respiratory distress may necessitate a tracheotomy. A cartilaginous tracheal sleeve replacing the normal C rings of cartilage has been found in several infants. These can be difficult to detect and their presence may have been responsible for breathing restrictions that has led to the demise of some children before two years of age.

Genetics

Reported cases have occurred sporadically.  Increased paternal age has been suggested as a factor in the occurrence of heterozygous mutations in the FGFR2 gene (10q26.13) which have been identified in some individuals.

Other forms of craniosynostosis in which mutations in FGFR2 have been found are: Crouzon Syndrome (123500), Pfeiffer Syndrome (101600), Apert Syndrome (101200), Jackson-Weiss Syndrome (123150), and Saethre-Chotzen Syndrome (101400).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no general treatment for this syndrome.  Several infants have had tracheotomies and CNS shunts.

References
Article Title: 

Beare-Stevenson cutis gyrata syndrome

Hall BD, Cadle RG, Golabi M, Morris CA, Cohen MM Jr. Beare-Stevenson cutis gyrata syndrome. Am J Med Genet. 1992 Sep 1;44(1):82-9. PubMed PMID: 1519658.

PubMed ID: 
1519658

Osteogenesis Imperfecta, Type VII

Clinical Characteristics
Ocular Features: 

Shallow orbits sometimes lead to severe and even progressive proptosis.  Bluish sclerae are sometimes present.

Systemic Features: 

Infants may be born with multiple fractures and adults are often short in stature.  Hypoplasia of the midface, frontal bossing, sutural craniosynostosis, hydrocephalus, and shallow orbits are frequently present and contribute to what is sometimes considered a distinctive facial dysmorphism.  Dentinogenesis imperfecta and hearing loss are variable features.  Neurological development is normal.

Multiple fractures occur and may result in marked long bone deformities, scoliosis, and short stature.  When the ribs are involved, respiratory insufficiency may result and can be responsible for early death.  Type VII osteogenesis imperfecta is sometimes considered a lethal form of OI. 

Genetics

Homozygous mutations in the CRTAP gene (3p22.3) are responsible for this condition.  This gene codes for a cartilage-associated protein and in mice is highly expressed in chondrocytes at growth plates and around the chondroosseous junction.  

This condition has been confused with Cole-Carpenter 1 syndrome (112240) but the latter is due to heterozygous mutations in P4HB (17q25.3) (PDI gene family).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Fractures require stabilization and hydrocephalus, if present, needs to be treated promptly.  Extreme proptosis can lead to inadequate hydration of the eye (especially the cornea) that may require lid surgery or orbital reconstruction.

References
Article Title: 

CRTAP mutation in a patient with Cole-Carpenter syndrome

Balasubramanian M, Pollitt RC, Chandler KE, Mughal MZ, Parker MJ, Dalton A, Arundel P, Offiah AC, Bishop NJ. CRTAP mutation in a patient with Cole-Carpenter syndrome. Am J Med Genet A. 2015 Jan 21. doi: 10.1002/ajmg.a.36916. [Epub ahead of print].

PubMed ID: 
25604815

New case of Cole-Carpenter syndrome

Amor DJ, Savarirayan R, Schneider AS, Bankier A. New case of Cole-Carpenter syndrome. Am J Med Genet. 2000 Jun 5;92(4):273-7. Review.

PubMed ID: 
10842295

Roberts Syndrome

Clinical Characteristics
Ocular Features: 

The eyes often appear prominent as the result of shallow orbits.  Hypertelorism and microphthalmia can be present.  The sclerae can have a bluish hue.   Cataracts and central corneal clouding plus scleralization and vascularization of the peripheral corneas are sometimes seen.  Lid colobomas and down-slanting palpebral fissures may be present.

Systemic Features: 

Failure of both membranous and long bones to grow properly lead to a variety of abnormalities such as craniosynostosis, hypomelia, syndactyly, oligodactyly, malar hypoplasia, short neck, micrognathia, and cleft lip and palate.  The long bones of the limbs may be underdeveloped or even absent.  Contractures of elbow, knee, and ankle joints are common as are digital anomalies.  Low birth weight and slow postnatal growth rates are usually result in short stature.  The hair is often sparse and light-colored. 

Mental development is impaired and some children are diagnosed to have mental retardation.  Cardiac defects are common.  Facial hemangiomas are often present as are septal defects and sometimes a patent ductus arteriosus.  External genitalia in both sexes appear enlarged.  The kidneys may be polycystic or horseshoe-shaped.

Genetics

This is an autosomal recessive condition caused by mutations in the ESCO2 gene (8p21.1).  Mutations in the same gene are also responsible for what some have called the SC phocomelia syndrome (269000) which has a similar but less severe phenotype.  Some consider the two disorders to be variants of the same condition and they are considered to be the same entity in this database.  The gene product is required for structural maintenance of centromeric cohesion during the cell cycle.  Microscopic anomalies of the centromeric region (puffing of the heterochromatic regions) are sometimes seen during cell division.

The Baller-Gerold syndrome (218600) has some phenotypic overlap with Roberts syndrome but is caused by mutations in a different gene (RECQL4).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Severely affected infants may be stillborn or die in infancy.  Other individuals live to adulthood.  There is no treatment for this condition beyond specific correction of individual anomalies.

References
Article Title: 

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: 

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).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

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

References
Article Title: 

Carpenter syndrome

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

PubMed ID: 
19165041

RAB23 mutations in Carpenter syndrome imply an unexpected role for hedgehog signaling in cranial-suture development and obesity

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

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