optic atrophy

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

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

Optic Atrophy, Ophthalmoplegia, Myopathy, and Neuropathy

Clinical Characteristics
Ocular Features: 

Visual symptoms have an insidious onset in childhood with vision loss and progressive external ophthalmoplegia.  Ptosis may be evident later.  The optic atrophy is progressive.   ERG abnormalities have been reported but no pigmentary retinopathy has been seen.  Myopia is sometimes present.

Systemic Features: 

The extraocular signs and symptoms are variable and generally have a later onset.  Some patients have an early onset of sensorineural hearing loss.  Muscle cramps and hyperreflexia may occur with clonus and a spastic gait.  Ataxia seems to be common.  The neurological phenotype has been likened to muscular sclerosis, Kearns-Sayre syndrome, and spastic paraplegia.  Muscle biopsies show variable-sized and atrophic fibers.

Genetics

This is generally considered an autosomal dominant disorder secondary to mutations in the OPA1 gene.  It is allelic to optic atrophy 1 (165500) but may also be the same condition since the p.Arg247His mutation has been found in patients with both disorders.  This syndromic form of optic atrophy may also result from biallelic mutations in OPA1 in which the clinical disease is more severe and earlier in onset. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment is available for the neurological disease but low vision aids should be considered to selected patients especially during childhood educational activities.

References
Article Title: 

Multi-system neurological disease is common in patients with OPA1 mutations

Yu-Wai-Man P, Griffiths PG, Gorman GS, Lourenco CM, Wright AF, Auer-Grumbach M, Toscano A, Musumeci O, Valentino ML, Caporali L, Lamperti C, Tallaksen CM, Duffey P, Miller J, Whittaker RG, Baker MR, Jackson MJ, Clarke MP, Dhillon B, Czermin B, Stewart JD, Hudson G, Reynier P, Bonneau D, Marques W Jr, Lenaers G, McFarland R, Taylor RW, Turnbull DM, Votruba M, Zeviani M, Carelli V, Bindoff LA, Horvath R, Amati-Bonneau P, Chinnery PF. Multi-system neurological disease is common in patients with OPA1 mutations. Brain. 2010 Mar;133(Pt 3):771-86.

PubMed ID: 
20157015

Retinitis Pigmentosa 38

Clinical Characteristics
Ocular Features: 

This is a rare clinically heterogeneous condition in which both rods and cones functions are variably affected.  It is a progressive disorder with children often being aware of night vision difficulties during the latter half of the first decade of life.  Reduced vision is often present at this time as well and progressively deteriorates.  Visual fields are constricted to 20-30 degrees.  Rod responses may be nondetectable in the first decade.

Central vision is subnormal as early as childhood and progressively worsens with age.  Dyschromatopsia to some degree is often present early as well and some patients have a maculopathy with a bull’s eye pattern and thinning of the photoreceptor layer seen on OCT.  Attenuated retinal vessels, pale optic discs, and variable fundus pigmentary changes (including pigmentary mottling and bone spicules) have been seen.  The degree and course of the photoreceptor damage is variable leading some to propose that RP38 is primarily a cone-rod dystrophy.

Systemic Features: 

None

Genetics

This is an autosomal recessive disorder resulting from homozygous mutations in the MERTK gene (2q13).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported but young people especially could benefit from low vision aids and special education therapy.

References
Article Title: 

Retinal Cone Dystrophy 3B

Clinical Characteristics
Ocular Features: 

This is a degenerative disorder in which patients have a progressive deterioration of visual acuity and color vision.  Most patients have significant myopia.  Visual difficulties begin in early childhood with acuity of 20/100 or worse by the second decade of life.  Color vision deficits can be detected in the second decade but nyctalopia occurs later in young adults.  Photophobia is a prominent symptom.  The ERG shows reduced and delayed cone responses.  Rod responses to low intensity flashes are undetectable but increased stimulus intensity leads to an abrupt increase in amplitude, often exceeding the upper limits of normal.

The fundus appears normal in some patients but foveal or parafoveal atrophy, a macular bull’s eye, hyperfluorescence anomalies, and a generalized fine pigmentary retinopathy have been reported.  There may be some temporal pallor in the optic nerves.  Nystagmus and strabismus may be present.

Systemic Features: 

No systemic disease has been reported.

Genetics

This is an autosomal recessive disorder resulting from homozygous or compound heterozygous mutations in the KCNV2 gene (9p24.2).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment is available for this dystrophy.  Low vision aids and tinted lenses may be helpful.

References
Article Title: 

Charcot-Marie-Tooth Disease(s)

Clinical Characteristics
Ocular Features: 

Optic atrophy is present in some patients, particularly in X-linked recessive (CMTX5; 311070), X-linked dominant (CMTX5; 302800), and autosomal recessive (CMT2A2B; 617087) disease.  Congenital and juvenile-onset open-angle glaucoma has been reported among members of 2 consanguineous families with type 4B2, or CMT4B2; (604563).  The mean age of onset was 8 years.

Systemic Features: 

Charcot-Marie-Tooth disease is a large group of clinically and genetically heterogeneous disorders characterized by progressive motor and sensory polyneuropathy.  These can be separated (with overlap) into two large groups on the basis of electrophysiologic criteria: type 1 is the demyelinating form, and type 2 the axonal form.  Patients with primarily distal motor neuropathy are sometimes considered to comprise a third type.

 Symptoms such as weakness in the extremities and digits have a variable age of onset but usually become evident in late childhood or early adulthood.  Small muscles of the hands and feet are often atrophied to some degree.  Some patients develop hearing loss of the neurosensory type.  Foot deformities such as pes cavus are common.  Nerve conduction velocity (reduction) and electromyography can be helpful diagnostically.  It may be helpful to look for characteristic changes such as loss of myelinated fibers and focal myelin sheath folding in sural nerve biopsies.  Intellectual impairment and dementia are usually not features of Charcot-Marie-Tooth disease.

Hemizygous individuals with X-linked types of CMT such as CMTX2-5 seem to be more likely to have intellectual disabilities, hearing loss, spasticity, and optic neuropathy.

Genetics

Charcot-Marie-Tooth disease can also be classified on the basis of their hereditary patterns including autosomal dominant, autosomal recessive, X-linked recessive, and X-linked dominant.  Each of these contains yet more distinct subtypes as defined by mutations in at least 40 genes.

The wide range of disease severity and the overlapping of many signs can make pedigree construction and the determination of recurrence risks and prognosis challenging.  The only recourse may be genotyping.

See Charcot-Marie-Tooth Disease with Glaucoma (604563) for a form of this disease in which glaucoma occurs early.

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

The widespread and debilitating polyneuropathy requires a multidisciplinary management approach with neurologists, physical and occupational therapists, audiologists, pain specialists, and orthopedists.  Pharmaceuticals such as gabapentin may be used for neuropathic pain.  Surgery for pes cavus and joint dysplasias can be helpful.

References
Article Title: 

Charcot-Marie-Tooth disease

Carter GT, Weiss MD, Han JJ, Chance PF, England JD. Charcot-Marie-Tooth disease. Curr Treat Options Neurol. 2008 Mar;10(2):94-102.

PubMed ID: 
18334132

Mutations in MTMR13, a new pseudophosphatase homologue of MTMR2 and Sbf1, in two families with an autosomal recessive demyelinating form of Charcot-Marie-Tooth disease associated with early-onset glaucoma

Azzedine H, Bolino A, Taieb T, Birouk N, Di Duca M, Bouhouche A, Benamou S, Mrabet A, Hammadouche T, Chkili T, Gouider R, Ravazzolo R, Brice A, Laporte J, LeGuern E. Mutations in MTMR13, a new pseudophosphatase homologue of MTMR2 and Sbf1, in two families with an autosomal recessive demyelinating form of Charcot-Marie-Tooth disease associated with early-onset glaucoma. Am J Hum Genet. 2003 May;72(5):1141-53.

PubMed ID: 
12687498

GAPO Syndrome

Clinical Characteristics
Ocular Features: 

Progressive optic atrophy is considered part of this syndrome but it is not a consistent feature.  One patient with the suspected diagnosis had papilledema while other individuals may have congenital glaucoma, buphthalmos, band keratopathy, and keratoconus.  White eyelashes have been described.  Myelinated nerve retinal nerve fibers may be prominent.

Systemic Features: 

This is a rare congenital disorder with so far incomplete phenotypic delineation. The diagnosis can be made soon after birth from the general facial and body morphology.  The dysmorphism is secondary to marked bone growth retardation and metaphyseal dysplasia, resulting in a flat midface, frontal bossing, micrognathism, chest deformities, and vertebral anomalies. Psychomotor retardation is common but the extent of cognitive deficits is unknown.  The permanent teeth may begin to develop but fail to erupt (pseudoanodontia). Even primary dentition is often abnormal.  Alopecia is a feature although some individuals do have sparse body hair, at least for a period of time.  Anomalous blood vessels such as dilated scalp veins are sometimes evident.   Hypogonadism has been reported in both sexes.  Individuals are subject to recurrent ear and respiratory infections. 

Genetics

GAPO occurs in both sexes.  Homozygous mutations in the ANTXR1 gene (2p13.3) are responsible for this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Treatment is directed at individual problems.  Prompt treatment of respiratory infections is important.

References
Article Title: 

Mutations in ANTXR1 cause GAPO syndrome

Stranecky V, Hoischen A, Hartmannova H, Zaki MS, Chaudhary A, Zudaire E, Noskova L, Baresova V, Pristoupilova A, Hodanova K, Sovova J, Hulkova H, Piherova L, Hehir-Kwa JY, de Silva D, Senanayake MP, Farrag S, Zeman J, Martasek P, Baxova A, Afifi HH, St Croix B, Brunner HG, Temtamy S, Kmoch S. Mutations in ANTXR1 cause GAPO syndrome. Am J Hum Genet. 2013 May 2;92(5):792-9.

PubMed ID: 
23602711

Ophthalmic findings in GAPO syndrome

Ilker SS, Ozturk F, Kurt E, Temel M, Gul D, Sayli BS. Ophthalmic findings in GAPO syndrome. Jpn J Ophthalmol. 1999 Jan-Feb;43(1):48-52.

PubMed ID: 
10197743

Spastic Paraplegia 2

Clinical Characteristics
Ocular Features: 

Nystagmus is common but variable in age of onset, and half of affected individuals have optic atrophy.

Systemic Features: 

This is a complex form of spastic paraplegia in which primarily lower limb spasticity is associated with dysarthria, sensory disturbances, cognitive deficits, muscle wasting and mild ataxia.  There is, however, considerable variability in age of onset and rate of symptom progression.  The first motor symptoms are often evident when children start walking, which is often delayed and clumsy.  However, evidence of spasticity may be present in children under 1 year of age.   Some patients have normal mental functions while others are considered mentally retarded.  The MRI reveals patchy leukodystrophy and degeneration of both corticospinal and spinocerebellar tracks was found in an autopsied individual.  Progression is relentless with many individuals requiring assistive devices such as crutches or walkers by early adult life.

Genetics

This is an X-linked disorder secondary to a mutation in the PLP1 gene at Xq22.2which codes for 2 major proteins found in myelin.  SPG2 is allelic to the more severe Pelizaeus-Merzbacher disease (312080).

Treatment
Treatment Options: 

Mobility devices and physical therapy can be helpful, especially in younger individuals.

References
Article Title: 

Spinocerebellar Ataxia, Infantile-Onset

Clinical Characteristics
Ocular Features: 

Ocular problems begin by about age 7 years when various degrees of ophthalmoplegia appear.  By the second decade damage to the optic nerves is evident (optic atrophy) leading to severe vision loss.

Systemic Features: 

This mitochondrial DNA depletion syndrome allows normal development in the first year of life.  By 10-18 months of age, muscle weakness and coordination become evident.  Deep tendon reflexes are diminished or absent.  The muscle deficits are relentlessly progressive and by teenage years most individuals are wheelchair-bound.  Generalized seizures are common.  Facial and limb dyskinesia of an athetoid nature is evident to a variable degree.  A sensory polyneuropathy develops in many patients.  Cerebellar atrophy is evident on neuroimaging.

Neurosensory hearing loss may become evident late in the first decade of life.  The amount of hearing loss is progressive, leading eventually to profound deafness.  Some patients experience a complete loss of vestibular caloric responses. 

Most individuals live to adulthood but a severe form of this disease in which liver damage and encephalopathy occur limits the lifespan to about 5 years.

Genetics

This infantile-onset form of spinocerebellar atrophy results from homozygous or compound heterozygous mutations in the C10ORF2 gene (10q24) which encodes the so-called Twinkle and Twinky mitochondrial proteins. Since the Twinkle protein is involved in the production and maintenance of mitochondrial DNA, its malfunction leads to reduced quantities of mtDNA in the liver and CNS but not in skeletal muscle.

Mutations in the C10ORF2 gene affecting the Twinkle protein may be responsible for an autosomal dominant progressive ophthalmoplegia (609286) in which ptosis and cataracts are often found but the more extensive muscle and sensory deficits are often missing.  This is one of the better examples of seemingly unique, allelic phenotypes resulting from different mutations in the same gene.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment has been reported but physical therapy, assistive hearing devices, and low vision aids might be helpful in selected patients.

References
Article Title: 

Infantile onset spinocerebellar ataxia caused by compound heterozygosity for Twinkle mutations and modeling of Twinkle mutations causing recessive disease

Pierce SB, Gulsuner S, Stapleton GA, Walsh T, Lee MK, Mandell JB, Morales A, Klevit RE, King MC, Rogers RC. Infantile onset spinocerebellar ataxia caused by compound heterozygosity for Twinkle mutations and modeling of Twinkle mutations causing recessive disease. Cold Spring Harb Mol Case Stud. 2016 Jul;2(4):a001107. doi: 10.1101/mcs.a001107.

PubMed ID: 
27551684

Retinitis Pigmentosa 25

Clinical Characteristics
Ocular Features: 

There is considerable clinical heterogeneity with a wide range in age of onset and progression.  Night blindness, sometimes with photophobia, has its onset in the second or third decade of life and central acuity can be impacted by age 30 years.  Other patients have no symptoms until the fifth decade.  Some patients lose the ability to perceive light by the sixth decade.  The visual fields are usually constricted although one patient had a central scotoma.  The ERG is usually nonrecordable but other patients may have a variable rod-cone pattern of attenuation.  The retinal vessels are also attenuated and some patients have mild optic atrophy.  The pigmentary retinopathy is also variable with sometimes central lesions and in other patients more peripheral.  One patient had posterior subcapsular cataracts.

Systemic Features: 

No systemic disease has been reported.

Genetics

This is an autosomal recessive form of retinitis pigmentosa resulting from homozygosity or compound heterozygosity in the EYS gene (6q12).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment has been reported.

References
Article Title: 

Pages

Subscribe to RSS - optic atrophy