high-arched eyebrows

Kabuki Syndrome 2

Clinical Characteristics
Ocular Features: 

The facial features are characteristic primarily because of the appearance of the periocular features.  The eyebrows are highly arched and sparse.  The lid fissures are long with eversion of the lateral portion of the lower eyelid.  The eyelashes are bushy.  Nystagmus and strabismus have been reported.

Systemic Features: 

Only a small number of individuals with Kabuki syndrome 2 have been reported and the phenotype is incompletely described.  Most of the features in type 2 are similar to those in type 1 with defects in multiple organs.  There are often cardiac malformations including septal defects.  Otitis media and hearing loss are common.  The pinnae are large and cupped.  A highly arched or cleft palate may be present and the teeth are usually small.  The joints are highly mobile and general hypotonia is often present. The fifth finger is often short and clinodactylous.  Persistent fetal fingerpads are common.  The amount of intellectual disability varies considerably with some patients functioning normally.  Urogenital anomalies are less common than found in Kabuki syndrome 1 and anal malformations do not seem to be a feature.

Genetics

Kabuki syndrome 2 is an X-linked disorder, usually as the result of a mutation in the KDM6A gene (Xp11.3).   Patients with the X-linked form of Kabuki represent about 5-10% of cases.   

Kabuki syndrome 1 (147920) is an autosomal dominant condition caused by heterozygous mutations in the KMT2D gene but remaining heterogeneity is suggested by the fact that a substantial proportion (30%) of individuals with Kabuki syndrome features has neither of these mutations.

In a 3 generation family two males had the typical Kabuki phenotype whereas their mother and grandmother (all had the KMT2D mutation) had various attenuated features.

Treatment
Treatment Options: 

Management guidelines are available (Management of Kabuki Syndrome).

References
Article Title: 

Molecular analysis, pathogenic mechanisms, and readthrough therapy on a large cohort of Kabuki syndrome patients

Micale L, Augello B, Maffeo C, Selicorni A, Zucchetti F, Fusco C, De Nittis P, Pellico MT, Mandriani B, Fischetto R, Boccone L, Silengo M, Biamino E, Perria C, Sotgiu S, Serra G, Lapi E, Neri M, Ferlini A, Cavaliere ML, Chiurazzi P, Monica MD, Scarano G, Faravelli F, Ferrari P, Mazzanti L, Pilotta A, Patricelli MG, Bedeschi MF, Benedicenti F, Prontera P, Toschi B, Salviati L, Melis D, Di Battista E, Vancini A, Garavelli L, Zelante L, Merla G. Molecular analysis, pathogenic mechanisms, and readthrough therapy on a large cohort of Kabuki syndrome patients. Hum Mutat. 2014 Jul;35(7):841-50.

PubMed ID: 
24633898

Baraitser-Winter Syndrome 1

Clinical Characteristics
Ocular Features: 

Ptosis (both unilateral and bilateral), hypertelorism, prominent epicanthal folds, and colobomata are common.  The iris stroma may be dysplastic and correctopia has been observed.  Visual acuity has not been measured.

Systemic Features: 

Postnatal growth retardation leads to short stature.  Microcephaly and morphological aberrations in the brain such as lissencephaly, agenesis of the corpus callosum and pachygyria are present.  Seizures and developmental delays are common.  Hearing loss is sensorineural in type.

The ears are low-set and the posterior hair line may be low as well.  The nasal bridge appears broad and the nose appears short. Male genitalia are often underdeveloped.  Bicuspid aortic valves, patent ductus arteriosus, and aortic stenosis have been reported.

Genetics

Heterozygous mutations in the ACTB gene (7p22.1) are responsible for this apparent autosomal dominant syndrome.  However, all patients have been sporadic.

This condition is clinically similar to Baraitser-Winter syndrome 2 (614583) which is a unique entity caused by a mutation in ACTG1. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No specific treatment is available.

References
Article Title: 

New ocular finding in Baraitser-Winter syndrome

Rall N, Leon A, Gomez R, Daroca J, Lacassie Y. New ocular finding in Baraitser-Winter syndrome. Eur J Med Genet. 2017 Oct 9. pii: S1769-7212(17)30156-8. doi: 10.1016/j.ejmg.2017.10.006. [Epub ahead of print].

PubMed ID: 
29024830

Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases

Verloes A, Di Donato N, Masliah-Planchon J, Jongmans M, Abdul-Raman OA, Albrecht B, Allanson J, Brunner H, Bertola D, Chassaing N, David A, Devriendt K, Eftekhari P, Drouin-Garraud V, Faravelli F, Faivre L, Giuliano F, Guion Almeida L, Juncos J, Kempers M, Eker HK, Lacombe D, Lin A, Mancini G, Melis D, Lourenco CM, Siu VM, Morin G, Nezarati M, Nowaczyk MJ, Ramer JC, Osimani S, Philip N, Pierpont ME, Procaccio V, Roseli ZS, Rossi M, Rusu C, Sznajer Y, Templin L, Uliana V, Klaus M, Van Bon B, Van Ravenswaaij C, Wainer B, Fry AE, Rump A, Hoischen A, Drunat S, Riviere JB, Dobyns WB, Pilz DT. Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases. Eur J Hum Genet. 2014 Jul 23.

PubMed ID: 
25052316

De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome

Riviere JB, van Bon BW, Hoischen A, Kholmanskikh SS, O'Roak BJ, Gilissen C, Gijsen S, Sullivan CT, Christian SL, Abdul-Rahman OA, Atkin JF, Chassaing N, Drouin-Garraud V, Fry AE, Fryns JP, Gripp KW, Kempers M, Kleefstra T, Mancini GM, Nowaczyk MJ, van Ravenswaaij-Arts CM, Roscioli T, Marble M, Rosenfeld JA, Siu VM, de Vries BB, Shendure J, Verloes A, Veltman JA, Brunner HG, Ross ME, Pilz DT, Dobyns WB. De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome. Nat Genet. 2012 Feb 26;44(4):440-4.

PubMed ID: 
22366783
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