nystagmus

Orofaciodigital Syndrome, Type VI

Clinical Characteristics
Ocular Features: 

Hypertelorism and epicanthal folds have been described.  Some patients have nystagmus and strabismus. Ocular apraxia and difficulties in smooth visual pursuit may be present.   

Systemic Features: 

Polydactyly of the hands is a common feature.  The central metacarpal is often Y-shaped leading to ‘central polydactyly’.  The large toes may be bifid.  Cognitive deficits are common and some patients have been considered mentally retarded.  The ears are low-set and rotated posteriorly.  Some patients have a conductive hearing loss.  Oral anomalies may include a lobed tongue, lingual and sublingual hemartomas, micrognathia, clefting, and multiple buccoalveolar frenula.  Congenital heart anomalies, micropenis, and cryptorchidism have been reported.  Tachypnea and tachycardia have been noted.  Some patients have some degree of skeletal dysplasia and many individuals are short in stature.

The presence of cerebellar abnormalities such as hypoplasia (including absence) of the vermis may help to distinguish type VI from other forms of OFDS.  Hypothalamic dysfunction may be responsible for poor temperature regulation (hyperthermia). The ‘molar tooth sign’ seen on brain MRIs in Joubert syndrome (213300) is also present in OFDS VI. 

Genetics

This is a rare condition with limited family information.  Parents in one family were consanguineous, and multiple affected sibs in other families suggest this may be an autosomal recessive condition.  Homozygous mutations in TMEM216 have been found. Other patients have mutations in C5orf42.

Many of the clinical features in OFDS VI are also found among individuals with Joubert (213300) and Meckel (249000) syndromes that also sometimes have mutations in the TMEM216 and C5orf42 genes.  Some consider all of these conditions to be members of a group of overlapping disorders called ciliopathies or ciliary dyskinesias.   

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No specific treatment is available for this syndrome but individual signs and symptoms may need treatment.

References
Article Title: 

C5orf42 is the major gene responsible for OFD syndrome type VI

Lopez E, Thauvin-Robinet C, Reversade B, Khartoufi NE, Devisme L, Holder M, Ansart-Franquet H, Avila M, Lacombe D, Kleinfinger P, Kaori I, Takanashi JI, Le Merrer M, Martinovic J, No?'l C, Shboul M, Ho L, G?oven Y, Razavi F, Burglen L, Gigot N, Darmency-Stamboul V, Thevenon J, Aral B, Kayserili H, Huet F, Lyonnet S, Le Caignec C, Franco B, Rivi?(r)re JB, Faivre L, Atti?(c)-Bitach T. C5orf42 is the major gene responsible for OFD syndrome type VI. Hum Genet. 2013 Nov 1. [Epub ahead of print].

PubMed ID: 
24178751

Mutations in TMEM216 perturb ciliogenesis and cause Joubert, Meckel and related syndromes

Valente EM, Logan CV, Mougou-Zerelli S, Lee JH, Silhavy JL, Brancati F, Iannicelli M, Travaglini L, Romani S, Illi B, Adams M, Szymanska K, Mazzotta A, Lee JE, Tolentino JC, Swistun D, Salpietro CD, Fede C, Gabriel S, Russ C, Cibulskis K, Sougnez C, Hildebrandt F, Otto EA, Held S, Diplas BH, Davis EE, Mikula M, Strom CM, Ben-Zeev B, Lev D, Sagie TL, Michelson M, Yaron Y, Krause A, Boltshauser E, Elkhartoufi N, Roume J, Shalev S, Munnich A, Saunier S, Inglehearn C, Saad A, Alkindy A, Thomas S, Vekemans M, Dallapiccola B, Katsanis N, Johnson CA, Atti?(c)-Bitach T, Gleeson JG. Mutations in TMEM216 perturb ciliogenesis and cause Joubert, Meckel and related syndromes. Nat Genet. 2010 Jul;42(7):619-25.

PubMed ID: 
20512146

Nystagmus 7, Congenital, AD

Clinical Characteristics
Ocular Features: 

A pendular nystagmus is usually diagnosed in infancy.  The eye is otherwise anatomically and functionally normal.  No photophobia, hypopigmentation, night blindness have been noted in the two Chinese families reported.  The ERG and foveal appearance are normal.  Visual acuity has not been reported.

Systemic Features: 

No systemic abnormalities have been found.

Genetics

The two reported multigenerational pedigrees show a pattern consistent with autosomal dominant inheritance. No causative mutation has been identified but mapping suggests a locus at 1q31-q32.2 that segregates with the condition.

Nystagmus 2 (164100), nystagmus 3 (608345), and nystagmus 4 (614826) are other autosomal dominant forms of simple nystagmus but they are unique disorders as they map to other chromosomal locations.

Several forms of X-linked recessive inheritance are contained in this database: NYS1, NYS5, and NYS6.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported. 

References
Article Title: 

Nystagmus 6, Congenital, X-linked

Clinical Characteristics
Ocular Features: 

In several Chinese families, nystagmus was limited to males with onset in one case in the first 6 months.  Foveal dysplasia was present along with mottled fundus pigmentation.  Carrier females did not have nystagmus or changes in fundus pigmentation (except for one with mottling). Vision is in the range of 20/50-20/60.

Systemic Features: 

Skin and hair pigmentation was normal. No systemic disease was identified.

Genetics

Mutations in GPR143 (Xp22.2) have been identified in this form of nystagmus. The family pedigrees are consistent with X-linked recessive inheritance.

Two additional X-linked isolated nystagmus conditions are contained in this database: nystagmus 1 (310700), the result of mutations in FRMD7, and nystagmus 5 (300589) of unknown gene causation.

Several autosomal dominant forms have been linked to chromosomal regions 6p12 (NYS2; 164100), 7p11 (NYS3, 608345), 13q (NYS4, 193003), 1q31.3-q32.1, and NYS7 (614826).  Autosomal recessive inheritance has been proposed for several pedigrees but adequate documentation is lacking (see 257400).

Ocular albinism (OA1) (300500) can also result from mutations in GPR143.  However, there was no evidence of ocular or systemic hypopigmentation in the Chinese families.

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

No treatment has been reported.

References
Article Title: 

Aprataxin gene mutations in Tunisian families

Amouri R, Moreira MC, Zouari M, El Euch G, Barhoumi C, Kefi M, Belal S, Koenig M, Hentati F. Aprataxin gene mutations in Tunisian families. Neurology. 2004 Sep 14;63(5):928-9.

PubMed ID: 
15365154

Nystagmus 5, Congenital, X-linked

Clinical Characteristics
Ocular Features: 

In the single 4 generation French family reported nystagmus was the only ocular finding.  It is present at birth or within the first year of life.  Visual acuity has not been reported.

Systemic Features: 

None reported.

Genetics

The pattern of inheritance is uncertain.  Both sexes may be affected but no male-to-male transmission was documented in the single family reported.  Apparent incomplete penetrance makes analysis difficult since several unaffected females transmitted the phenotype to male offspring.

No mutation has been identified but a possible locus within Xp11.4-p11.3 may contain the mutant gene.

Autosomal dominant transmission patterns have been reported in other families: NYS2, NYS3, NYS4, and NYS7.

This database contains several additional forms of congenital nystagmus inherited in X-linked recessive patterns: NYS1, and NYS6.

Pedigree: 
X-linked dominant, mother affected
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Nystagmus 4, AD

Clinical Characteristics
Ocular Features: 

Abnormal eye movements generally are present as early as 1 to 2 years of life and are stable but they are not congenital in origin.  Eye movement anomalies are somewhat variable and unusual with gaze-paretic nystagmus and poor or absent smooth pursuit most common.  The nystagmus may also be upbeat in direction.  A poor vestibuloocular reflex might be part of this eye movement complex.  Vision in many individuals is normal but mildly decreased in others.  Strabismus (primarily esotropia and exophoria) is common.

Systemic Features: 

Mild "balance problems" have been reported by some patients.  One individual reported intermittent dizziness.  No other cerebellar signs are present.  Neuroimaging found no CNS abnormalities in one patient. Seizures and ataxia were separately reported in two persons.

Genetics

The single reported family shows a transmission pattern consistent with autosomal dominant inheritance.  A locus cosegregating with the condition has been found at 13q31-q33 but no specific mutation has been identified.

Only one family has been reported and additional information is needed to document the uniqueness of this disorder.

Other autosomal dominant congenital nystagmus conditions in this database are: NYS2, NYS3, and NYS7.

Three X-linked isolated congenital nystagmus conditions may also be found in this database: NYS1, NYS5, and NYS6.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported.  Low vision aids might be helpful for school-age children.

References
Article Title: 

Albinism, Oculocutaneous, Type VII

Clinical Characteristics
Ocular Features: 

Nystagmus and iris transillumination are present in all family members studied.  VEP studies show asymmetric decussation of axons in the chiasm.  The peripheral retina may have striking hypopigmentation. OCT reveals hypoplasia of the foveal region.   Photophobia is not a significant problem. Visual acuity is mildly to moderately reduced.

Systemic Features: 

Homozygous individuals are lighter in complexion than other family members. Hair color ranges from pale blond to dark brown.

Genetics

Homozygous mutations in the C10orf11 gene (10q22.2-q22.3) are responsible for the phenotype of this autosomal recessive condition.  The gene is active in melanocyte differentiation.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment for the hypopigmentation has been reported.  Visual function might be improved with low vision aids.

References
Article Title: 

Increasing the complexity: new genes and new types of albinism

Montoliu L, Gronskov K, Wei AH, Martinez-Garcia M, Fernandez A, Arveiler B, Morice-Picard F, Riazuddin S, Suzuki T, Ahmed ZM, Rosenberg T, Li W. Increasing the complexity: new genes and new types of albinism. Pigment Cell Melanoma Res. 2014 Jan;27(1):11-18. Review.

PubMed ID: 
24066960

Nystagmus 3, Congenital, AD

Clinical Characteristics
Ocular Features: 

The nystagmus is horizontal in type and accentuated by fixation and decreased by convergence.  It also increases during smooth pursuit and by lateral gaze.  There may be components of jerk, circular, and pendular nystagmus.  The nystagmus may be present at birth.

Systemic Features: 

No systemic disease is present.   

Genetics

No specific mutation has been found but 3 individuals in one family shared a haplotype suggesting a locus at 7p11.2.  The pedigree pattern suggests autosomal dominant inheritance.  A four generation family with male to male transmission and a balanced 7;15 translocation has been reported with a similar phenotype.

Other forms of congenital nystagmus transmitted in a similar autosomal pattern are: NYS2, NYS4, and NYS7.

X-linked recessive transmission patterns have also been identified for congenital nystagmus: NYS1, NYS5, and NYS6.

 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no effective cure for congenital nystagmus but some patients can benefit from extraocular muscle surgery, correction of refractive errors, and low vision aids.

References
Article Title: 

Nystagmus 2, Congenital, AD

Clinical Characteristics
Ocular Features: 

Pendular and sometimes jerk nystagmus are often present at birth.  Other patients are diagnosed between 3 and 6 months.  Vision is usually stable in the range of 20/30 to 20/100 with most patients having 20/50.  Between 35% and 50% of individuals have strabismus as well.

Systemic Features: 

None have been reported.

Genetics

Familial cases have an autosomal dominant transmission pattern.  No specific mutation has been found but strong linkage with a region at 6p12 has been reported.

Several additional autosomal dominant forms of congenital nystagmus have been linked to chromosomal regions 7p11 (NYS3, 608345), 13q (NYS4, 193003), 1q31.3-q32.1, and NYS7 (614826).  Autosomal recessive inheritance has been proposed for several pedigrees but adequate documentation is lacking (see 257400).

This database also contains 3 types of congenital nystagmus inherited in X-linked recessive patterns: NYS1, NYS5, and NYS6.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Nystagmus cannot be cured.  However, there are several treatments that can help.  Glasses and contact lenses, and, occasionally, extraocular muscle surgery may be helpful.  The latter should be considered especially when patients adopt a consistent head position for best vision.  This avoids long-term secondary changes in neck muscles and many individuals experience an improvement of two or more lines in visual acuity.  Low vision aids should be offered.

References
Article Title: 

Albinism, Oculocutaneous, Type VI

Clinical Characteristics
Ocular Features: 

Nystagmus is usually present from birth and visual acuity is in the range of 20/100.  There is marked hypopigmentation in the retina and the iris often transilluminates.  OCT usually shows foveal flattening consistent with hypoplasia.  Most patients experience severe photophobia and many have strabismus.

Systemic Features: 

There is usually complete loss or a severe reduction of melanin in skin, hair, and eyes.  Hair color is blond but may become tinged with brown in older individuals.  The skin may have pigmented nevi and has a tendency to tan in some patients.

Genetics

This is an autosomal recessive disorder resulting from mutations in SLC24A5 (15q21.1).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment is available.  Visual function can be improved with low vision aids.

References
Article Title: 

SLC24A5 Mutations are Associated with Non-Syndromic Oculocutaneous Albinism

Morice-Picard F, Lasseaux E, Fran?ssois S, Simon D, Rooryck C, Bieth E, Colin E, Bonneau D, Journel H, Walraedt S, Leroy BP, Meire F, Lacombe D, Arveiler B. SLC24A5 Mutations are Associated with Non-Syndromic Oculocutaneous Albinism. J Invest Dermatol. 2013 Aug 28. [Epub ahead of print] PubMed PMID: 23985994.

PubMed ID: 
23985994

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: 

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