autosomal dominant

Myopathy, Mitochondrial Anomalies, and Ataxia

Clinical Characteristics
Ocular Features: 

Ocular findings are variable.  One of three individuals with compound heterozygous mutations had a pigmentary retinopathy with pallor of the optic nerve but no visual abnormalities.  Her sister had only optic nerve pallor.  The eyes are described as "small" and "close-set".

No ocular findings were reported for the family with autosomal dominant inheritance.

Systemic Features: 

Ataxia, short stature, and gait difficulties from an early age are consistent findings.  Some patients are never able to walk.  Motor development is generally delayed.  Truncal and limb ataxia is a feature.  Some degree of intellectual disability is generally present and speech is often delayed.  

The face is long with a myopathic appearance.  Both micrognathia and a prominent jaw may be seen.  The palate is highly arched.  Patients are described as hypotonic and there is generalized muscle weakness both proximal and distal.  Distal sensory impairment has been described in the family with presumed dominant inheritance and there may be psychiatric symptoms of anxiety, depression, and schizophrenia.  Dysmetria with dysdiadochokinesis is often present and a fine intention tremor has been observed.

Mitochondria in fibroblasts exhibit abnormal dynamics and occur in a fragmented network.  Muscle biopsies reveal changes consistent with myopathy.  Serum creatine kinase may be elevated.

Genetics

Compound heterozygous mutations in the MSTO1 gene (1q22) have been found in two families with 3 affected individuals suggesting autosomal recessive inheritance.  In a third family, heterozygous mutations in the same gene were found in a mother and 3 of her adult children, consistent with autosomal dominant transmission.

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Leber Congenital Amaurosis with Early-Onset Deafness

Clinical Characteristics
Ocular Features: 

Evidence for retinal disease can be seen within 3 years of age.  Three of 5 patients had no detectable responses on the ERG when tested at birth.  A 34-year-old female was noted to have advanced retinitis pigmentosa with attenuation of retinal vessels, choroidal atrophy, peripheral pigmentary deposits, and macular anomalies.  The posterior fundus may have a salt-and-pepper pigmentation.  Hypermetropia was present in all 5 patients.

Visual acuity varies widely and may be normal even among older patients.

Systemic Features: 

Mild to severe sensorineural hearing loss secondary to cochlear cell loss is usually diagnosed in the first decade.  All patients had normal neuro-psychomotor development.

Genetics

Heterozygous mutations in the TUBB4B gene (9q34.3) have been found in 5 individuals in 4 families with this disorder.  There may be significant mosaicism in blood cells.

See Leber Congenital Amaurosis for additional information on non-syndromal Leber congenital amaurosis and responsible mutations.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment is available for the general condition but refractive correction, low vision aids, and assistive hearing devices may be of benefit.

References
Article Title: 

Mutations in TUBB4B Cause a Distinctive Sensorineural Disease

Luscan R, Mechaussier S, Paul A, Tian G, Gerard X, Defoort-Dellhemmes S, Loundon N, Audo I, Bonnin S, LeGargasson JF, Dumont J, Goudin N, Garfa-Traore M, Bras M, Pouliet A, Bessieres B, Boddaert N, Sahel JA, Lyonnet S, Kaplan J, Cowan NJ, Rozet JM, Marlin S, Perrault I. Mutations in TUBB4B Cause a Distinctive Sensorineural Disease. Am J Hum Genet. 2017 Dec 7;101(6):1006-1012.

PubMed ID: 
29198720

Neurodevelopmental Disorder With or Without Seizures and Gait Abnormalities

Clinical Characteristics
Ocular Features: 

Nystagmus and strabismus are common ocular features.  Optic nerve hypoplasia is present in some individuals.

Systemic Features: 

Symptoms may begin in early infancy or childhood.  Several neonates with irritability, hypertonia, increased startle reflexes, and stiffness have been reported.  Hypotonia may occur in the neonatal period though.  Intellectual disability and severe developmental delay are common and some patients are unable to follow simple commands.  Seizures of variable severity frequently occur at some point.  Speech may be absent.  Some patients are unable to walk while those that do have a clumsy, spastic gait.  Joint contractures may develop.

The most obvious dysmorphic feature are large ears.  Choreiform and stereotypic hand movements are sometimes present.  Feeding difficulties and sleeping problems may be noted.  Cortical atrophy and thinning of the corpus callosum has been seen on brain imaging.  One mildly affected individual was short in stature.

Genetics

Heterozygous mutations in the GRIA4 gene (11q22.3) have been found in 5 unrelated patients.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Facial Palsy, Congenital, with Ptosis and Velopharyngeal Dysfunction

Clinical Characteristics
Ocular Features: 

The singular ocular feature found in this condition is congenital bilateral non-progressive ptosis which may improve to some extent with age.  Patients usually compensate with a chin up posture.  A mild paresis of upgaze and some weakness of the orbicularis oculi muscles has been described in the index case.  Ocular motility is otherwise normal and Bell's phenomenon is usually present. 

Systemic Features: 

Patients have a wide uvula, absent or decreased gag reflexes, and rhinophonia aperta.  Symptoms are nonprogressive but may improve with age or therapy.  No other skeletal, neurologic, or psychomotor anomalies have been reported.

Genetics

A single 5 generation family has been reported.  The transmission pattern is consistent with autosomal dominant inheritance.  Heterozygous missense mutations in the TUBB6 gene (18p11.21) are responsible for this condition.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Some patients benefit from nasopharyngeal surgery to improve swallowing and speech.  Ptosis surgery can also be helpful.

References
Article Title: 

A TUBB6 mutation is associated with autosomal dominant non-progressive congenital facial palsy, bilateral ptosis and velopharyngeal dysfunction

Fazeli W, Herkenrath P, Stiller B, Neugebauer A, Fricke J, Lang-Roth R, Nurnberg G, Thoenes M, Becker J, Altmuller J, Volk AE, Kubisch C, Heller R. A TUBB6 mutation is associated with autosomal dominant non-progressive congenital facial palsy, bilateral ptosis and velopharyngeal dysfunction. Hum Mol Genet. 2017 Oct 15;26(20):4055-4066.

PubMed ID: 
29016863

Choroidal Dystrophy, Central Areolar 2

Clinical Characteristics
Ocular Features: 

Slowly progressive loss of vision is noted in the 4th and 6th decades with a mean age of onset at 46 years. ERG recordings suggest that the cone dysfunction is more severe and occurs earlier than rod deterioration.  Night blindness is usually not a major complaint.  A central scotoma is usually present but peripheral fields may be relatively intact.  Dyschromatopsia is often present.  Early in the disease the RPE may have a granular appearance but in later stages there is usually a sharply demarcated area of central RPE atrophy (sometimes called geographic atrophy).

Autoflourescence, pattern ERGs, and fine matrix mapping can reveal abnormalities before patients become symptomatic.

Systemic Features: 

No systemic features are known.

Genetics

This is a clinically and genetically heterozygous disorder.  Multiple mutations in the PRPH2 gene (6p21.1) have been identified in this condition.  Some of the clinical variation may be mutation-specific.

For a somewhat similar disorder see choroidal dystrophy, central areolar 1 (215500).

CACD is a genetically heterogeneous disorder with mutations in several genes responsible.  The majority of patients have one of several mutations in the PRPH2 gene (6p21.1-cen) and the inheritance pattern seems to be autosomal recessive (CACD2).  Other family trees in which mutations in PRPH2 were excluded suggest autosomal dominant inheritance (CACD3; 613144).   

The gene product of PRPH2 is important to the integrity and stability of the structures that contain light-sensitive pigments (e.g., photoreceptors). More than 100 mutations have been identified. The resultant phenotype can be highly variable, even within members of the same family but most affected individuals have some degree of pigmentary retinopathy within the macula or throughout the posterior pole.

The altered gene product resulting from mutations in PRPH2 often leads to symptoms beginning in midlife as a result of the slow degeneration of photoreceptors. This database contains at least 11 disorders in which PRPH2 mutations have been found.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No effective treatment is known.

References
Article Title: 

Central areolar choroidal dystrophy

Boon CJ, Klevering BJ, Cremers FP, Zonneveld-Vrieling MN, Theelen T, Den Hollander AI, Hoyng CB. Central areolar choroidal dystrophy. Ophthalmology. 2009 Apr;116(4):771-82, 782.e1.

PubMed ID: 
19243827

Keratosis Follicularis Spinulosa Decalvans, AD

Clinical Characteristics
Ocular Features: 

This genodermatosis has signs and symptoms beginning in childhood.  Photophobia is a prominent symptom.  The eyebrows and eyelashes are thin and sparse.  Recurrent blepharitis and keratitis are often present.

Systemic Features: 

The scalp is often dry and scaly.  Scalp alopecia begins sometime in the first two decades of life and becomes a major complaint by the third or fourth decade.  The face and especially the cheeks are often erythematous.  The scalp can have multiple follicular pustules which are most prominent in the occipital and nuchal areas.  Follicular keratotic papules are often located on the trunk and extensor areas of the limbs.  Histology of scalp skin biopsies show epidermal hyperplasia and an extensive perifollicular inflammatory infiltrate.

Enamel hypoplasia result in multiple and recurrent caries and loss of teeth.  The nails are often dystrophic.

Genetics

This is likely an autosomal dominant disorder based on the transmission pattern of several reported families but no locus or mutation has been reported.

There is also an X-linked form of Keratosis Follicularis Spinulosa Decalvans (KFSDX) (308800) which is more common.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Dental surveillance and treatment are important.  Ocular lubrication can be helpful in severe cases and ophthalmic topical antibiotics may be useful in treatment of blepharitis and keratitis.Clinica

References
Article Title: 

Blepharocheilodontic Syndrome 2

Clinical Characteristics
Ocular Features: 

The eyelids are disproportionately large with ectropion of the lower lid.  There is often a duplicate row of lashes (distichiasis) and there may be lagophthalmos and euryblepharon present.  Hypertelorism has been described. 

Systemic Features: 

The teeth are often conical and some may be absent.  Cleft lip and palate are often present.  The forehead is prominent and the frontal hairline is posteriorly located.

Genetics

Heterozygous mutations in the CTNND1 gene (11q12.1) are responsible for this condition.

Blepharocheilodontic syndrome 1 results from heterozygous mutations in the CDH1 gene (16q22.1).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment consists of surgical repair of dental, eyelid, and oral defects.

References
Article Title: 

Spinocerebellar Ataxia 37

Clinical Characteristics
Ocular Features: 

 Abnormal ocular movements are common, beginning with dysmetric vertical saccades and irregularities of vertical pursuit, with later development of irregular horizontal tracking movements.  Nystagmus is sometimes present. 

Two otherwise asymptomatic individuals with dysmetric vertical saccades and irregular vertical pursuit movements had normal horizontal pursuit movements at the ages of 32 and 40 years and were found to have the SCA37 haplotype.   

Systemic Features: 

The mean age of onset in is about 50 years with signs of dysarthria and a clumsy gait.  Other more variable findings include truncal ataxia, dysmetria, and sometimes dysphagia.  Slow progression of signs may lead to eventual wheelchair dependence within one or two decades of disease onset.  Brain imaging reveals cerebellar atrophy with sparing of the brainstem.

Genetics

Heterozygous mutations in the DAB1 gene (1p32.2) are responsible for this disorder.   This disorder of adult onset has been described in several families living on the Iberian peninsula.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No effective treatment has been reported.

References
Article Title: 

A Pentanucleotide ATTTC Repeat Insertion in the Non-coding Region of DAB1, Mapping to SCA37, Causes Spinocerebellar Ataxia

Seixas AI, Loureiro JR, Costa C, Ordonez-Ugalde A, Marcelino H, Oliveira CL, Loureiro JL, Dhingra A, Brandao E, Cruz VT, Timoteo A, Quintans B, Rouleau GA, Rizzu P, Carracedo A, Bessa J, Heutink P, Sequeiros J, Sobrido MJ, Coutinho P, Silveira I. A Pentanucleotide ATTTC Repeat Insertion in the Non-coding Region of DAB1, Mapping to SCA37, Causes Spinocerebellar Ataxia. Am J Hum Genet. 2017 Jul 6;101(1):87-103.

PubMed ID: 
28686858

Familial Exudative Vitreoretinopathy, EVR7

Clinical Characteristics
Ocular Features: 

The ocular features are primarily limited to the posterior chamber where there are areas of retinal avascularity, exudation, retinal holes, and detachments.  Areas of degeneration and pigmentary retinopathy may be present.  Vascular proliferation may be part of the process with vitreous traction and folds.  Progression of retinal damage is highly variable and surgical outcomes are unpredictable.  Long term vision outcomes are sometimes as good as 20/40 but in many eyes NLP or hand motion vision is the end result.  

Secondary changes in the anterior chamber and cornea from repeated surgeries may lead to glaucoma, cataracts, and corneal decompensation. 

Systemic Features: 

There are no consistent systemic abnormalities.

Genetics

Missense and nonsense heterozygous mutations in the CTNNB1 gene (3p22.1) segregate with this autosomal dominant condition found in two families of Japanese origin.  A Chinese 3-year-old with FEVR having a single BP insertion in the CTNNB1 gene also had global developmental delay and dysmorphic facies.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

The prognosis for vision is poor as the retinal damage often continues to evolve and additional folds and detachments develop.  Attempts to close retinal holes and repair detachments are important.

References
Article Title: 

Defects in the Cell Signaling Mediator β-Catenin Cause the Retinal Vascular Condition FEVR

Panagiotou ES, Sanjurjo Soriano C, Poulter JA, Lord EC, Dzulova D, Kondo H, Hiyoshi A, Chung BH, Chu YW, Lai CHY, Tafoya ME, Karjosukarso D, Collin RWJ, Topping J, Downey LM, Ali M, Inglehearn CF, Toomes C. Defects in the Cell Signaling Mediator v-Catenin Cause the Retinal Vascular Condition FEVR. Am J Hum Genet. 2017 Jun 1;100(6):960-968.

PubMed ID: 
28575650

Spinocerebellar Ataxia 3

Clinical Characteristics
Ocular Features: 

External ophthalmoplegia in some form is usually present and there may be a supranuclear component.  Smooth horizontal movements are impaired and saccades are dysmetric.  Gaze-evoked nystagmus is a common finding.  The eyes are often described as 'bulging' and this has been attributed to eyelid retraction.  With time the abnormal saccadic movements slow resulting in ophthalmoparesis with restriction of upgaze.

Systemic Features: 

This form of spinocerebellar ataxia is considered to be the most frequent.  It is a progressive disease in all aspects which accounts for some of the considerable clinical heterogeneity reported.  Onset is likewise highly variable depending upon the number of repeats but usually sometime between the second to fifth decades.  In a large cohort of Azorean individuals the mean age of onset was reported to be 37 years.

An unsteady gait, dysarthric speech, general clumsiness, and diplopia are among the early symptoms.  Nystagmus, spasticity, and various autonomic signs including reduced bladder control may also be noted.  Chronic pain, sleep disturbances, impaired mental functioning, and memory deficits are often present and some authors have labelled these as indicative of dementia.

Virtually all clinical signs progress with ambulation difficulties requiring the need for assistive devices about a decade after the onset of disease.  Eventually signs of brain stem involvement appear with facial atrophy, perioral twitching, tongue fasciculations and atrophy, and dysphagia. Some degree of peripheral polyneuropathy with muscle wasting and loss of sensation are often present.  Tremors and other signs of Parkinsonism may be present.  Dystonic movements are often seen.

Imagining of the brain has revealed pontocerebellar atrophy and enlargement of the 4th ventricle but this is variable.  Nerve conduction studies documents involvement of the sensory nerves.  Neuropathologic studies show widespread neuronal loss in the CNS and spinal cord.

Genetics

This is considered to be an autosomal dominant disorder caused by an excess of heterozygous trinucleotide repeats in the ataxin3 gene (14q32) encoding glutamine.  The number in normal individuals is up to 44 repeats whereas patients with SCA3 have 52-86 repeats.  However, clinical signs of SCA3 have been found in patients with as few as 45 glutamine repeats.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Physical and occupational therapy combined with regular exercise has been reported to slow the progression of symptoms.

References
Article Title: 

Machado-Joseph disease

Sudarsky L, Coutinho P. Machado-Joseph disease. Clin Neurosci. 1995;3(1):17-22. Review.

PubMed ID: 
7614089

Pages

Subscribe to RSS - autosomal dominant