autosomal dominant

Optic Atrophy, Areflexia, Ataxia, Hearing Loss

Clinical Characteristics
Ocular Features: 

Progressive optic atrophy is a consistent feature of all reported cases.  It may have its onset during the first year or two of life but always before the age of 10 years.  Nystagmus may be seen early during acute febrile episodes but eventually becomes permanent.

Systemic Features: 

Onset of neurological symptoms usually occurs in childhood during or following an acute febrile illness which may be recurrent.  This may consist of cerebellar ataxia, hypotonia, drowsiness, dysarthria, and lethargy.  There may be partial or full recovery following the febrile illness initially but some signs remain after subsequent episodes.  Areflexia and sensorineural deafness can be additional signs and pes cavus eventually appears.

The acute febrile episodes tend to decrease in time along with the progression of neurological signs.  Plantar responses remain normal while peripheral neuropathy and seizures are not consistent features.  MRI imaging of the brain is normal.  Cognitive function usually remains normal but some children have autism features and social adjustment problems have been noted.

Genetics

This is an autosomal dominant condition (which may be considered a form of ‘ataxia-plus’) secondary to heterozygous mutations in the ATP1A3 gene (19q13.31).  The protein product is a subunit of an ATPase enzyme primarily active in neural tissue.

Other mutations in the same gene have been found in dystonia-12 and alternating hemiplegia of childhood.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment is known for this condition but physical therapy and mobility-assistive devices may be helpful.  Low vision aids may be useful as well.

References
Article Title: 

A novel recurrent mutation in ATP1A3 causes CAPOS syndrome

Demos MK, van Karnebeek CD, Ross CJ, Adam S, Shen Y, Zhan SH, Shyr C, Horvath G, Suri M, Fryer A, Jones SJ, Friedman JM; FORGE Canada Consortium. A novel recurrent mutation in ATP1A3 causes CAPOS syndrome. Orphanet J Rare Dis. 2014 Jan 28;9:15.

PubMed ID: 
24468074

Retinal Arteriolar Tortuosity

Clinical Characteristics
Ocular Features: 

The diameter of retinal arterioles and their degree of tortuosity are continuous metrics without specific endpoints. However, examination of the retinal vasculature can identify a set of patients in which the arterioles are strikingly tortuous. It is most evident in second and third order vessels.  In such individuals retinal hemorrhages may occur following mild trauma and exercise.  They are usually located in the posterior pole and may account for reported episodes of temporary vision loss if located in the foveal and parafoveal areas.  No vascular leakage is seen on fluorescein angiography.  The retinal hemorrhages usually resolve without permanent damage.  The vascular tortuosity seems to have its onset in the first two decades of life and has been described as progressive.

Systemic Features: 

Increased tortuosity of capillaries in the nail beds can be seen and some individuals have hematuria.

The phenotype in this condition is variable and seems to be specific to individual families.  There are families in which extraocular disease has been ruled out whereas in other families there may be small vessel disease in the brain, and yet other families in which nephropathy, muscle cramps, and aneurysms occur with the retinal arteriolar tortuosity.  Patients with systemic vascular disease frequently have evidence of leukoencephalopathy on brain scans.  There is a significant risk of major vascular accidents in the central nervous system.

Genetics

Heterozygous mutations in the COL4A1 gene (13q34) have been identified in families with simple retinal arteriolar tortuosity.  The gene product is a component of type IV collagen which is found in basement membranes throughout the body, including blood vessels.

Mutations in COL4A1 have also been found in the multisystem disease known as HANAC (Hereditary Angiopathy with Nephropathy, Aneurysm and Cramps) (611773) in which tortuosity of the retinal arterioles is also seen. 

Vascular tortuosity is also a feature of Fabry disease (301500) and Williams syndrome (194050).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment is known but patients should avoid strenuous excercise.

References
Article Title: 

Cranial Dysinnervation Disorders with Strabismus and Arthrogryposis

Clinical Characteristics
Ocular Features: 

Strabismus and/or ophthalmoplegia are important features of a group of conditions known as cranial dysinnervation disorders.  Ptosis, Duane syndrome, V pattern exotropia and various degrees of ophthalmoplegia may be seen.  There may be considerable asymmetry in the manifestations in the two eyes.  Epicanthal folds, blepharophimosis, and hypermetropia are sometimes present.  Some patients have corneal leukomas, keratoglobus, high corneal astigmatism, and dysplastic optic disks. 

A pigmentary retinopathy and folds in the macula with an abnormal ERG has been reported.  Subnormal vision has been reported in some patients.

Systemic Features: 

Patients are often short in stature with pectus excavatum, spine stiffness, highly arched palate, and club feet.  Limited forearm rotation and wrist extension may be present.  The fingers appear long and often have contractures while the palmar and phalangeal creases may be absent.  Camptodactyly and clinodactyly are common.  Deep tendon reflexes are often hyporeactive and decreased muscle mass has been noted.  The muscles seem "firm" to palpation.  Restrictive lung disease has been reported.  Hearing loss is experienced by some individuals.

Genetics

Distal arthrogryposis type 5D is caused by homozygous or compound heterozygous mutations in the ECEL1 gene located at 2q36.  However, a similar phenotype (albeit with more severe ocular manifestations) results from heterozygous mutations in PIEZO2 (18p11).  Heterozygous mutations in the PIEZO2 gene have also been reported to cause distal arthrogryposis type 3 (Gordon syndrome [114300]) and Marden-Walker syndrome (248700) and all of these may be simply phenotypical variations of the same disorder.

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

There is no treatment for this condition.  Patients with subnormal vision may benefit from low vision aids and selective surgery may be helpful in reducing the physical restrictions from physical deformities.

References
Article Title: 

Mutations in PIEZO2 cause Gordon syndrome, Marden-Walker syndrome, and distal arthrogryposis type 5

McMillin MJ, Beck AE, Chong JX, Shively KM, Buckingham KJ, Gildersleeve HI, Aracena MI, Aylsworth AS, Bitoun P, Carey JC, Clericuzio CL, Crow YJ, Curry CJ, Devriendt K, Everman DB, Fryer A, Gibson K, Giovannucci Uzielli ML, Graham JM Jr, Hall JG, Hecht JT, Heidenreich RA, Hurst JA, Irani S, Krapels IP, Leroy JG, Mowat D, Plant GT, Robertson SP, Schorry EK, Scott RH, Seaver LH, Sherr E, Splitt M, Stewart H, Stumpel C, Temel SG, Weaver DD, Whiteford M, Williams MS, Tabor HK, Smith JD, Shendure J, Nickerson DA; University of Washington Center for Mendelian Genomics, Bamshad MJ. Mutations in PIEZO2 cause Gordon syndrome, Marden-Walker syndrome, and distal arthrogryposis type 5. Am J Hum Genet. 2014 May 1;94(5):734-44.

PubMed ID: 
24726473

Optic Atrophy with Intellectual Disability

Clinical Characteristics
Ocular Features: 

Optic atrophy is the primary ocular abnormality but visual deficits are said to originate from cortical impairment.  The optic discs are pale and may be small with excavation.  Strabismus and latent nystagmus are often present. Up slanting palpebral fissures and epicanthal folds have been noted. Visual acuity levels have not been reported.

Systemic Features: 

Facial dysmorphism of a non-specific pattern can be present as evidenced by protruding ears with helical anomalies, and a small, sometimes elevated nasal bridge. The fingers are small and tapered.  Developmental delay is common.  Obsessive-compulsive behavior and autistic features have been reported in a single individual.  Hypotonia may be present.

Genetics

This is an autosomal dominant disorder resulting from heterozygous mutations in the NR2F1 gene (5q15), a transcription regulator.   Six persons with this condition have so far been reported.  The gene product is a nuclear protein active in transcription regulation during neurodevelopment.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Only symptomatic treatment is available.  Low vision aids and special education may be of benefit.

References
Article Title: 

NR2F1 mutations cause optic atrophy with intellectual disability

Bosch DG, Boonstra FN, Gonzaga-Jauregui C, Xu M, de Ligt J, Jhangiani S, Wiszniewski W, Muzny DM, Yntema HG, Pfundt R, Vissers LE, Spruijt L, Blokland EA, Chen CA; Baylor-Hopkins Center for Mendelian Genomics, Lewis RA, Tsai SY, Gibbs RA, Tsai MJ, Lupski JR, Zoghbi HY, Cremers FP, de Vries BB, Schaaf CP. NR2F1 mutations cause optic atrophy with intellectual disability. Am J Hum Genet. 2014 Feb 6;94(2):303-9.

PubMed ID: 
24462372

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

Microphthalmia, Syndromic 5

Clinical Characteristics
Ocular Features: 

One or both eyes may be small, sometimes resembling clinical anophthalmia. Other ocular anomalies such as coloboma, microcornea, cataracts, and hypoplasia or agenesis of the optic nerve have been reported.

A pigmentary retinopathy has been described.  The retinal vessels are often attenuated and sometimes sparse.  The optic nerves and chiasm are frequently absent or hypoplastic as seen on the MRI.  ERG and VEP responses are inconsistent but are generally abnormal indicating photoreceptor malfunction.  

Systemic Features: 

Patients have a variety of systemic abnormalities including pituitary dysfunction, joint laxity, hypotonia, agenesis of the corpus callosum, and seizures.  Hypothyroidism and deficiencies of growth hormone, gonadotropins, and cortisol are present in some patients.  Developmental delay and cognitive impairment are frequently present but mental functioning is normal in some patients.  The genitalia of males are often underdeveloped.  Patients are often short in stature.

Genetics

This is an autosomal dominant condition secondary to heterozygous mutations in the OTX2 gene (14q22.3).  A variety of point mutations as well as microdeletions involving the OTX2 gene have been reported.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment for the syndrome but surgical and/or endocrinological treatment may be used to correct individual features.  Special education and low vision aids may be helpful in selected patients.

References
Article Title: 

Heterozygous mutations of OTX2 cause severe ocular malformations

Ragge NK, Brown AG, Poloschek CM, Lorenz B, Henderson RA, Clarke MP, Russell-Eggitt I, Fielder A, Gerrelli D, Martinez-Barbera JP, Ruddle P, Hurst J, Collin JR, Salt A, Cooper ST, Thompson PJ, Sisodiya SM, Williamson KA, Fitzpatrick DR, van Heyningen V, Hanson IM. Heterozygous mutations of OTX2 cause severe ocular malformations. Am J Hum Genet. 2005 Jun;76(6):1008-22. Apr 21. Erratum in: Am J Hum Genet. 2005 Aug;77(2):334..

PubMed ID: 
15846561

Nanophthalmos 3

Clinical Characteristics
Ocular Features: 

A six generation Chinese family has been reported in which 12 affected members had small eyes, ptosis, apparent enophthalmos, shallow anterior chambers, and small corneas.  Hyperopic refractive errors ranged from +6.00 to +11.25 (mean +8.25).  

Systemic Features: 

None reported.

Genetics

The transmission pattern for this 6 generation family strongly suggests autosomal dominant inheritance.  No mutation has been identified but the 2q11-14 locus is strongly associated with the phenotype.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment has not been reported but monitoring for narrow angle glaucoma is advised.

References
Article Title: 

Nanophthalmos 1

Clinical Characteristics
Ocular Features: 

The axial length ranges from 17.55 to 19.28 mm with a mean of 18.13 mm.  The mean refractive error was +9.88 in one reported family but ranged from +7.25 to +13.00.  More than half of reported patients have developed angle closure glaucoma.  Patients are at risk for strabismus and amblyopia.  Choroidal detachments are often seen in nanophthalmic eyes.

Histological studies on full thickness sclerotomy tissue from a nanophthalmic eye showed frayed and split collagen fibrils with lightly stained cores predominantly in the sclera and episcleral regions which may contribute to the anatomical changes.

Systemic Features: 

None have been reported.

Genetics

No mutation has been described but this autosomal dominant condition maps to 11p.

Another type of autosomal dominant nanophthalmos (NNO3) (611897) maps to 2q22-q14, and yet another, nanophthalmos AD, results from mutations in TMEM98.

Nanophthalmos may also be inherited in an autosomal recessive pattern.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Lifelong monitoring is required because of the risk of angle closure.  Intraocular surgery such as lens extractions carries a high risk of complications.

References
Article Title: 

Nanophthalmos AD

Clinical Characteristics
Ocular Features: 

In the family reported, vision ranged from NLP to 20/20.  Refractive errors ranged from +8.25 to +15.50 D (mean +11.8 D).  Axial length ranged from 16.90 to 18.46 mm with a mean of 17.6 mm.  Angle closure glaucoma was diagnosed in 6 of 16 (37%) patients. Thickened sclera with prominent scleral vessels was described in affected family members.  Optic nerve drusen are often present and increased tortuosity of the retinal vessels has been described.

Systemic Features: 

No systemic abnormalities have been reported in spite of the fact that the TMEM98 gene is widely expressed in body tissues. 

Genetics

This is an autosomal dominant disorder resulting from a missense mutation in exon 8 of the TMEM98 (17p12-q12) gene.  The mutation has been reported in a single Australian family.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Lens removal may be considered in individuals with shallow anterior chambers and narrow angles but frequent postoperative macular edema and choroidal effusions have been seen and the visual prognosis is guarded.

References
Article Title: 

Blepharocheilodontic Syndrome 1

Clinical Characteristics
Ocular Features: 

The eyelids are disproportionately large with an associated lagophthalmos and lower lid ectropion.  The upper eyelids may have a double row of lashes (distichiasis).  Hypertelorism and a broad nasal root have been reported.

Systemic Features: 

A cleft lip and palate are major features and are usually bilateral.  The teeth are conically shaped with microdontia and oligodontia (involving both primary and secondary dentition) often present as well.  Several newborns have had an imperforate anus. Scalp hair may be sparse and hypoplastic nails have been described.  Hypothyroidism and thyroid agenesis has been documented in several patients.

Genetics

This is an autosomal dominant condition resulting from mutations in the CDH1 gene (16q22.1).

Blepharocheilodontic syndrome 2 is caused by mutations in the CTNND1 gene (16q22.1).

Other conditions with distichiasis include Blatt distichiasis (126300) and lymphedema-distichiasis (153400).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment consists of correction of individual anomalies such as eyelid, oral, and dental malformations.

References
Article Title: 

Blepharo-cheilo-dontic (BCD) syndrome

Gorlin RJ, Zellweger H, Curtis MW, Wiedemann HR, Warburg M, Majewski F, Gillessen-Kaesbach G, Prahl-Andersen B, Zackai E. Blepharo-cheilo-dontic (BCD) syndrome. Am J Med Genet. 1996 Oct 16;65(2):109-12.

PubMed ID: 
8911600

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