Clinically, there is an acute onset of visual loss, first in one eye, and then a few weeks to months later in the other. Onset is usually young adulthood, but age range at onset from 7-75 is reported. The age of onset is slightly higher in females (range 19–55 years: mean 31.3 years) than males (range 15–53 years: mean 24.3). The male to female ratio varies between mutations: 3:1 for 3460 G>A, 6:1 for 11778 G>A and 8:1 for 14484 T>C.

This typically evolves to very severe optic atrophy and a permanent decrease of visual acuity. Both eyes become affected either simultaneously (25% of cases) or sequentially (75% of cases) with a median inter-eye delay of 8 weeks. Rarely only one eye may be affected. In the acute stage, lasting a few weeks, the affected eye demonstrates an edematous appearance of the nerve fiber layer especially in the arcuate bundles and enlarged or telangiectatic and tortuous peripapillary vessels (microangiopathy). The main features are seen on fundus examination, just before or subsequent to the onset of visual loss. A pupillary defect may be visible in the acute stage as well. Examination reveals decreased visual acuity, loss of color vision and a cecocentral scotoma on visual field examination.

Familial exudative vitreoretinopathy (FEVR) ( ) is a genetic disorder affecting the growth and development of blood vessels in the retina of the eye. This disease can lead to visual impairment and sometimes complete blindness in one or both eyes. FEVR is characterized by exudative leakage and hemorrhage of the blood vessels in the retina, along with incomplete vascularization of the peripheral retina. The disease process can lead to retinal folds, tears, and detachments.

Onset : Early childhood

Progression: Chronic progressive

Clinical: Cerebellar ataxia plus syndrome / Optic Atrophy Plus Syndrome

Ocular: Optic atrophy, nystagmus, scotoma, and bilateral retrobulbar neuritis.

Other: Mental retardation, myoclonic epilepsy, spasticity, and posterior column sensory loss. Tremor in some cases.

Musculoskeletal

Contractures, lower limbs, Achilles tendon contractures, Hamstring contractures, Adductor longus contractures

Systemic

Hypogonadotrophic hypogonadism.

"LHON Plus" is a name given to a rare variant of the disorder with eye disease together with other conditions. The symptoms of this higher form of the disease include loss of the brain's ability to control the movement of muscles, tremors, and cardiac arrhythmia. Many cases of LHON plus have been comparable to multiple sclerosis because of the lack of muscular control.

The most common malformation in patients with the syndrome is kidney hypodysplasia, which are small and underdeveloped kidneys, often leading to end-stage renal disease (ESRD). Estimates show approximately 10% of children with hypoplastic kidneys are linked to the disease. Many different histological abnormalities have been noted, including:

- decrease in nephron number associated with hypertrophy

- focal segmental glomerulosclerosis

- interstitial fibrosis and tubular atrophy

- multicystic dysplastic kidney

Up to one-third of diagnosed patients develop end stage kidney disease, which may lead to complete kidney failure.

FEVR is, as its name suggests,

familial and can be inherited in an

autosomal dominant, autosomal

recessive or X-linked recessive pattern.1-3 It is caused by mutations in

FZD4, LRP5, TSPAN12 and NDP

genes, which impact the wingless/

integrated (Wnt) receptor signaling

pathway. 3 Disruption of this path

way leads to abnormalities of vascu-

lar growth in the peripheral retina. 2,3

It is typically bilateral, but asymmetric, with varying degrees of

progression over the individual’s

lifetime. Age of onset varies, and

visual outcome can be strongly

influenced by this factor. Patients

with onset before age three have a

more guarded long-term prognosis

whereas those with later onset are

more likely to have asymmetric

presentation with deterioration of

vision in one eye only. 2-3 However,

because FEVR is a lifelong disease,

these patients are at risk even as

adults.2 Ocular findings and useful

vision typically remain stable if the

patient does not have deterioration

before age 20.2,4 Due to the variability and unpredictability of the

disease course, patients with FEVR

should be followed throughout

their lifetime.

Clinical presentation can vary

greatly. In mild variations, patients

may experience peripheral vascular

changes, such as peripheral avascular zone, vitreoretinal adhesions,

arteriovenous anastomoses and a

V-shaped area of retinochoroidal

degeneration. 4 Severe forms may

present with neovascularization,

subretinal and intraretinal hemorrhages and exudation. 4 Neovascularization is a poor prognostic

indicator and can lead to retinal

folds, macular ectopia and tractional retinal detachment. 2,4 Widefield FA has been crucial in

helping to understand this disease,

as well as helping to confirm the

diagnosis. An abrupt cessation

of the retinal capillary network

in a scalloped edge posterior to

fibrovascular proliferations can

be made using FA.2,3,5 Patients can

also show delayed transit filling on

FA as well as delayed/patchy choroidal filling, bulbous vascular terminals, capillary dropout, venous/venous shunting and abnormal

branching patterns. 2,3,5 The staging of FEVR is similar

to that of retinopathy of prematurity. The first two stages involve an

avascular retinal periphery with or

without extraretinal vascularization (stage 1 and 2, respectively). 4 Stages three through five delineate

levels of retinal detachment; stage 3

is subtotal without foveal involvement, stage 4 is subtotal with foveal

involvement and stage 5 is a total

detachment, open or closed funnel.4

Because there was neovascularization in the absence of retinal detachment, our patient was

considered to have

stage 2.

Patients with Stargardt disease usually develop symptoms in the mid-first to the late second decade of life, with age of onset which can be as early as ~6 years of age. The main symptom of Stargardt disease is loss of visual acuity, uncorrectable with glasses, which progresses and frequently stabilizes between 20/200 and 20/400. Other symptoms include wavy vision, blind spots (scotomata), blurriness, impaired color vision, and difficulty adapting to dim lighting (delayed dark adaptation). The disease sometimes causes sensitivity to glare; overcast days offer some relief. Vision is most noticeably impaired when the macula (center of retina and focus of vision) is damaged, leaving peripheral vision more intact. Generally, vision loss starts within the first 20 years of life.

Examination with an ophthalmoscope shows few notable findings in the early stages of the disease. Eventually, however, an oval-shaped atrophy with a horizontal major axis appears in the retinal pigment epithelium, and has the appearance of beaten bronze, along with sparing of the area surrounding the optic disc (peripapillary sparing). Techniques such as fundus autofluorescence (FAF), Optical Coherence Tomography (OCT), or less frequently fluorescein angiography, can detect early signs before they are visible ophthalmoscopically.

Autosomal Dominant Retinal Vasculopathy with Cerebral Leukodystrophy (AD-RVCL) (previously known also as Cerebroretinal Vasculopathy, CRV, or Hereditary Vascular Retinopathy, HVR or Hereditary Endotheliopathy, Retinopathy, Nephropathy, and Stroke, HERNS) is an inherited condition resulting from a frameshift mutation to the TREX1 gene. This genetically inherited condition affects the retina and the white matter of the central nervous system, resulting in vision loss, lacunar strokes and ultimately dementia. Symptoms commonly begin in the early to mid-forties, and treatments currently aim to manage or alleviate the symptoms rather than treating the underlying cause. The overall prognosis is poor, and death can sometimes occur within 10 years of the first symptoms appearing.

AD-RVCL (CRV) Acronym

Autosomal Dominance (genetics) means only one copy of the gene is necessary for the symptoms to manifest themselves.

Retinal Vasculopathy means a disorder that is associated with a disease of the blood vessels in the retina.

Cerebral means having to do with the brain.

Leukodystrophy means a degeneration of the white matter of the brain.

Pathogenesis

The main pathologic process centers on small blood vessels that prematurely “drop out” and disappear. The retina of the eye and white matter of the brain are the most sensitive to this pathologic process. Over a five to ten-year period, this vasculopathy (blood vessel pathology) results in vision loss and destructive brain lesions with neurologic deficits and death.

Most recently, AD-RVCL (CRV) has been renamed. The new name is CHARIOT which stands for Cerebral Hereditary Angiopathy with vascular Retinopathy and Impaired Organ function caused by TREX1 mutations.

Treatment

Currently, there is no therapy to prevent the blood vessel deterioration.

About TREX1

The official name of the TREX1 gene is “three prime repair exonuclease 1.” The normal function of the TREX1 gene is to provide instructions for making the 3-prime repair exonuclease 1 enzyme. This enzyme is a DNA exonuclease, which means it trims molecules of DNA by removing DNA building blocks (nucleotides) from the ends of the molecules. In this way, it breaks down unneeded DNA molecules or fragments that may be generated during genetic material in preparation for cell division, DNA repair, cell death, and other processes.

Changes (mutations) to the TREX1 gene can result in a range of conditions one of which is AD-RVCL. The mutations to the TREX1 gene are believed to prevent the production of the 3-prime repair exonuclease 1 enzyme. Researchers suggest that the absence of this enzyme may result in an accumulation of unneeded DNA and RNA in cells. These DNA and RNA molecules may be mistaken by cells for those of viral invaders, triggering immune system reactions that result in the symptoms of AD-RVCL.

Mutations in the TREX1 gene have also been identified in people with other disorders involving the immune system. These disorders include a chronic inflammatory disease called systemic lupus erythematosus (SLE), including a rare form of SLE called chilblain lupus that mainly affects the skin.

The TREX1 gene is located on chromosome 3: base pairs 48,465,519 to 48,467,644

The immune system.

- The immune system is composed of white blood cells or leukocytes.

- There are 5 different types of leukocytes.

- Combined, the 5 different leukocytes represent the 2 types of immune systems (The general or innate immune system and the adaptive or acquired immune system).

- The adaptive immune system is composed of two types of cells (B-cells which release antibodies and T-cells which destroy abnormal and cancerous cells).

How the immune system becomes part of the condition.

During mitosis, tiny fragments of “scrap” single strand DNA naturally occur inside the cell. Enzymes find and destroy the “scrap” DNA. The TREX1 gene provides the information necessary to create the enzyme that destroys this single strand “scrap” DNA. A mutation in the TREX1 gene causes the enzyme that would destroy the single strand DNA to be less than completely effective. The less than completely effective nature of the enzyme allows “scrap” single strand DNA to build up in the cell. The buildup of “scrap” single strand DNA alerts the immune system that the cell is abnormal.

The abnormality of the cells with the high concentration of “scrap” DNA triggers a T-cell response and the abnormal cells are destroyed. Because the TREX1 gene is identical in all of the cells in the body the ineffective enzyme allows the accumulation of “scrap” single strand DNA in all of the cells in the body. Eventually, the immune system has destroyed enough of the cells in the walls of the blood vessels that the capillaries burst open. The capillary bursting happens throughout the body but is most recognizable when it happens in the eyes and brain because these are the two places where capillary bursting has the most pronounced effect.

Characteristics of AD-RVCL

- No recognizable symptoms until after age 40.

- No environmental toxins have been found to be attributable to the condition.

- The condition is primarily localized to the brain and eyes.

- Optically correctable, but continuous, deterioration of visual acuity due to extensive multifocal microvascular abnormalities and retinal neovascularization leading, ultimately, to a loss of vision.

- Elevated levels of alkaline phosphatase.

- Subtle vascular changes in the retina resembling telangiectasia (spider veins) in the parafovea circulation.

- Bilateral capillary occlusions involving the perifovea vessels as well as other isolated foci of occlusion in the posterior pole of the retina.

- Headaches due to papilledema.

- Mental confusion, loss of cognitive function, loss of memory, slowing of speech and hemiparesis due to “firm masses” and white, granular, firm lesions in the brain.

- Jacksonian seizures and grand mal seizure disorder.

- Progressive neurologic deterioration unresponsive to systemic corticosteroid therapy.

- Discrete, often confluent, foci of coagulation necrosis in the cerebral white matter with intermittent findings of fine calcium deposition within the necrotic foci.

- Vasculopathic changes involving both arteries and veins of medium and small caliber present in the cerebral white matter.

- Fibroid necrosis of vessel walls with extravasation of fibrinoid material into adjacent parenchyma present in both necrotic and non-necrotic tissue.

- Obliterative fibrosis in all the layers of many vessel walls.

- Parivascular, adventitial fibrosis with limited intimal thickening.

Conditions with similar symptoms that AD-RVCL can be misdiagnosed as:

- Brain tumors

- Diabetes

- Macular degeneration

- Telangiectasia (Spider veins)

- Hemiparesis (Stroke)

- Glaucoma

- Hypertension (high blood pressure)

- Systemic Lupus Erythematosus (SLE (same original pathogenic gene, but definitely a different disease because of a different mutation in TREX1))

- Polyarteritis nodosa

- Granulomatosis with polyangiitis

- Behçet's disease

- Lymphomatoid granulomatosis

- Vasculitis

Clinical Associations

- Raynaud's phenomenon

- Anemia

- Hypertension

- Normocytic anemia

- Normochromic anemia

- Gastrointestinal bleeding or telangiectasias

- Elevated alkaline phosphatase

Definitions

- Coagulation necrosis

- Endothelium

- Fibrinoid

- Fibrinoid necrosis

- Frameshift mutation

- Hemiparesis

- Jacksonian seizure

- Necrotic

- Necrosis

- Papilledema

- Perivascular

- Retinopathy

- Telangiectasia

- Vasculopathy

- Vascular

What AD-RVCL is not:

- Infection

- Cancer

- Diabetes

- Glaucoma

- Hypertension

- A neurological disorder

- Muscular dystrophy

- Systemic Lupus Erythematosis (SLE)

- Vasculitis

Things that have been tried but turned out to be ineffective or even make things worse:

- Antibiotics

- Steroids

- X-Ray therapy

- Immunosuppression

History of AD-RVCL (CRV)

- 1985 – 1988: CRV (Cerebral Retinal Vasculopathy) was discovered by John P. Atkinson, MD at Washington University School of Medicine in St. Louis, MO

- 1988: 10 families worldwide were identified as having CRV

- 1991: Related disease reported, HERNS (Hereditary Endiotheliopathy with Retinopathy, Nephropathy and Stroke – UCLA

- 1998: Related disease reported, HRV (Hereditary Retinal Vasculopathy) – Leiden University, Netherlands

- 2001: Localized to Chromosome 3.

- 2007: The specific genetic defect in all of these families was discovered in a single gene called TREX1

- 2008: Name changed to AD-RVCL Autosomal Dominant-Retinal Vasculopathy with Cerebral Leukodystrophy

- 2009: Testing for the disease available to persons 21 and older

- 2011: 20 families worldwide were identified as having CRV

- 2012: Obtained mouse models for further research and to test therapeutic agents

The initial retinal degenerative symptoms of retinitis pigmentosa are characterized by decreased night vision (nyctalopia) and the loss of the mid-peripheral visual field. The rod photoreceptor cells, which are responsible for low-light vision and are orientated in the retinal periphery, are the retinal processes affected first during non-syndromic forms of this disease. Visual decline progresses relatively quickly to the far peripheral field, eventually extending into the central visual field as tunnel vision increases. Visual acuity and color vision can become compromised due to accompanying abnormalities in the cone photoreceptor cells, which are responsible for color vision, visual acuity, and sight in the central visual field. The progression of disease symptoms occurs in a symmetrical manner, with both the left and right eyes experiencing symptoms at a similar rate.

A variety of indirect symptoms characterize retinitis pigmentosa along with the direct effects of the initial rod photoreceptor degeneration and later cone photoreceptor decline. Phenomena such as photophobia, which describes the event in which light is perceived as an intense glare, and photopsia, the presence of blinking or shimmering lights within the visual field, often manifest during the later stages of RP. Findings related to RP have often been characterized in the fundus of the eye as the "ophthalamic triad". This includes the development of (1) a mottled appearance of the retinal pigment epithelium (RPE) caused by bone spicule formation, (2) a waxy appearance of the optic nerve, and (3) the attentuation of blood vessels in the retina.

Non-syndromic RP usually presents a variety of the following symptoms:

- Night blindness

- Tunnel vision (due to loss of peripheral vision)

- Latticework vision

- Photopsia (blinking/shimmering lights)

- Photophobia (aversion to glare)

- Development of bone spicules in the fundus

- Slow adjustment from dark to light environments and vice versa

- Blurring of vision

- Poor color separation

- Loss of central vision

- Eventual blindness

Ocular disc dysplasia is the most notable ocular defect of the disease. An abnormal development in the optic stalk causes optic disc dysplasia, which is caused by a mutation in the "Pax2" gene. The nerve head typically resembles the morning glory disc anomaly, but has also been described as a coloboma. A coloboma is the failure to close the choroid fissure, which is the opening from the ventral side of the retina in the optic stalk. Despite the similarities with coloboma and morning glory anomaly, significant differences exist such that optic disc dysplasia cannot be classified as either one entity.

Optic disc dysplasia is noted by an ill-defined inferior excavation, convoluted origin of the superior retinal vessels, excessive number of vessels, infrapapillary pigmentary disturbance, and slight band of retinal elevation adjacent to the disk. Some patients have normal or near normal vision, but others have visual impairment associated with the disease, though it is not certain if this is due only to the dysplastic optic nerves, or a possible contribution from macular and retinal malformations. The retinal vessels are abnormal or absent, in some cases having small vessels exiting the periphery of the disc. There is a great deal of clinical variability.

Usually, pseudoxanthoma elasticum affects the skin first, often in childhood but frequently later. Small, yellowish papular lesions form and cutaneous laxity mainly affects the neck, axillae (armpits), groin, and flexural creases (the inside parts of the elbows and knees). Skin may become lax and redundant. Many individuals have "oblique mental creases" (diagonal grooves of the chin).

PXE first affects the retina through a dimpling of the Bruch membrane (a thin membrane separating the blood vessel-rich layer from the pigmented layer of the retina), that is only visible during ophthalmologic examinations. This is called peau d'orange (a French term meaning that the retina resembles the skin of an orange). Eventually the mineralization of the elastic fibers in the Bruch membrane create cracks (angioid streaks) that radiate out from the optic nerve. Angioid streaks themselves do not cause distortion of vision, even if they cross into the foveal area. This symptom is present in almost all PXE patients and is usually noticed a few years after the onset of cutaneous . These cracks may allow small blood vessels that were originally held back by Bruch's membrane to penetrate the retina. These blood vessels sometimes leak, and these retinal hemorrhages may lead to the loss of central vision. Vision loss is a major issue in many PXE patients.

PXE may affect the gastrointestinal and cardiovascular systems. In the digestive tract, the principal symptom is gastrointestinal bleeding, usually from the stomach. This occurs in a very small number of patients. In the circulatory system, intermittent claudication (leg pain during walking which resolves at rest) is a prominent feature, although at later stages coronary artery disease may develop, leading to angina and myocardial infarction (heart attack) may occur.

The first symptom of this disease is usually a slow loss of vision. Early signs of Retinitis include loss of night vision; making it harder to drive at night. Later signs of retinitis include loss of peripheral vision, leading to tunnel vision. In some cases, symptoms are experienced in only one of the eyes. Experiencing the vision of floaters, flashes, blurred vision and loss of side vision in just one of the eyes is an early indication of the onset of Retinitis.

Behr syndrome is characterized by the association of early-onset optic atrophy with spinocerebellar degeneration resulting in ataxia, pyramidal signs, peripheral neuropathy and developmental delay.

Although it is an autosomal recessive disorder, heterozygotes may still manifest much attenuated symptoms. Autosomal dominant inheritance also being reported in a family. Recently a variant of OPA1 mutation with phenotypic presentation like Behr syndrome is also described. Some reported cases have been found to carry mutations in the OPA1, OPA3 or C12ORF65 genes which are known causes of pure optic atrophy or optic atrophy complicated by movement disorder.

Wagner's disease is a familial disease of the eye that can cause reduced visual acuity. Wagner's disease was originally described in 1938. This disorder was frequently confused with Stickler syndrome, but lacks the systemic features and high incidence of retinal detachments. Inheritance is autosomal dominant.

Most patients with ML IV show psychomotor retardation (i.e., delayed development of movement and coordination), corneal opacity, retinal degeneration and other ophthalmological abnormalities. Other symptoms include agenesis of the corpus callosum, iron deficiency resulting from an absence of acid secretion in the stomach, achlorhydria. Achlorhydria in these patients results in an increase in blood gastrin levels. These symptoms typically manifest early in life (within the first year). After disease onset there occurs a period of stability, typically lasting two to three decades during which very little disease progression occurs.

In general, PRAs are characterised by initial loss of rod photoreceptor cell function followed by that of the cones and for this reason night blindness is the first significant clinical sign for most dogs affected with PRA. As other retinal disorders, PRA can be divided into either dysplastic disease, where the cells develop abnormally, and degenerative, where the cells develop normally but then degenerate during the dog's lifetime.

Generalized PRA is the most common type and causes atrophy of all the neural retinal structures. Central progressive retinal atrophy (CPRA) is a different disease from PRA involving the retinal pigment epithelium (RPE), and is also known as retinal pigment epithelial dystrophy (RPED).

RP may be:

(1) Non-syndromic, that is, it occurs alone, without any other clinical findings,

(2) Syndromic, with other neurosensory disorders, developmental abnormalities, or complex clinical findings, or

(3) Secondary to other systemic diseases.

- RP combined with deafness (congenital or progressive) is called Usher syndrome.

- Alport's syndrome is associated with RP and an abnormal glomerular-basement membrane leading nephrotic syndrome and inherited as X-linked dominant.

- RP combined with ophthalmoplegia, dysphagia, ataxia, and cardiac conduction defects is seen in the mitochondrial DNA disorder Kearns-Sayre syndrome (also known as Ragged Red Fiber Myopathy)

- RP combined with retardation, peripheral neuropathy, acanthotic (spiked) RBCs, ataxia, steatorrhea, is absence of VLDL is seen in abetalipoproteinemia.

- RP is seen clinically in association with several other rare genetic disorders (including muscular dystrophy and chronic granulomatous disease) as part of McLeod syndrome. This is an X-linked recessive phenotype characterized by a complete absence of XK cell surface proteins, and therefore markedly reduced expression of all Kell red blood cell antigens. For transfusion purposes these patients are considered completely incompatible with all normal and K0/K0 donors.

- RP associated with hypogonadism, and developmental delay with an autosomal recessive inheritance pattern is seen with Bardet-Biedl syndrome

Other conditions include neurosyphilis, toxoplasmosis and Refsum's disease.

Stargardt disease, or fundus flavimaculatus, is the most frequent form of inherited juvenile macular degeneration. Stargardt causes progressive vision loss usually to the point of legal blindness. Several genes are associated with the disorder. Symptoms, mainly central vision loss, typically develop before age 20 (median age of onset: ~17 years old), and also include wavy vision, blind spots, blurriness, impaired color vision, and difficulty adapting to dim lighting (dark adaptation delays).

Stargardt is often used to refer to any juvenile macular dystrophy; however, it properly refers to atrophic macular dystrophy with yellow, poorly-defined flecks surrounding the macula in the retinal pigment epithelium.

Autosomal dominant optic atrophy can present clinically as an isolated bilateral optic neuropathy (non-syndromic form) or rather as a complicated phenotype with extra-ocular signs (syndromic form).

Dominant optic atrophy usually affects both eyes roughly symmetrically in a slowly progressive pattern of vision loss beginning in childhood and is hence a contributor to childhood blindness. Vision testing will reveal scotomas (areas of impaired visual acuity) in the central visual fields with peripheral vision sparing and impaired color vision (color blindness). Visual acuity loss varies from mild to severe, typically ranging from 6/6 (in meters, equivalent to 20/20, ft) to 6/60 (20/200, ft) with a median value of 6/36 (roughly equivalent to 20/125 ft), corrected vision. In rare cases, vision loss is more severe.

Characteristic changes of the fundus evident on examination is temporal pallor (indicating atrophy) of the optic disc and in its end stage, excavation of the optic disc, as is also seen in Leber hereditary optic neuropathy and normal tension glaucoma.

Because the onset of Dominant optic atrophy is insidious, symptoms are often not noticed by the patients in its early stages and are picked up by chance in routine school eye screenings. First signs of Kjer's typically present between 4–6 years of age, though presentation at as early as 1 year of age has been reported. In some cases, Dominant optic atrophy may remain subclinical until early adulthood.

Progression of dominant optic atrophy varies even within the same family. Some have mild cases with visual acuity stabilizing in adolescence, others have slowly but constantly progressing cases, and others still have sudden step-like decreases in visual acuity. Generally, the severity of the condition by adolescence reflects the overall level of visual function to be expected throughout most of the patient’s adult life (Votruba, 1998). Slow decline in acuity is known to occur in late middle age in some families.

In complicated cases of autosomal dominant optic atrophy, in addition to bilateral optic neuropathy, several other neurological signs of neurological involvement can be observed: peripheral neuropathy, deafness, cerebellar ataxia, spastic paraparesis, myopathy.

Progressive retinal atrophy (PRA) is a group of genetic diseases seen in certain breeds of dogs and, more rarely, cats. Similar to retinitis pigmentosa in humans, it is characterized by the bilateral degeneration of the retina, causing progressive vision loss culminating in blindness. The condition in nearly all breeds is inherited as an autosomal recessive trait, with the exception of the Siberian Husky (inherited as an X chromosome linked trait) and the Bullmastiff (inherited as an autosomal dominant trait). There is no treatment.

Common symptoms of the disease are weakness and atrophy in the distal muscles of the lower limbs which progresses to the hands and arms, then to the trunk, neck and face. Respiratory impairment often follows.

Dominant optic atrophy, or dominant optic atrophy, Kjer's type, is an autosomally inherited disease that affects the optic nerves, causing reduced visual acuity and blindness beginning in childhood. This condition is due to mitochondrial dysfunction mediating the death of optic nerve fibers. Dominant optic atrophy was first described clinically by Batten in 1896 and named Kjer’s optic neuropathy in 1959 after Danish ophthalmologist Poul Kjer, who studied 19 families with the disease. Although dominant optic atrophy is the most common autosomally inherited optic neuropathy (i.e., disease of the optic nerves) aside from glaucoma, it is often misdiagnosed.

Vitelliform macular dystrophy causes a fatty yellow pigment (lipofuscin) to build up in cells underlying the macula. The retinal pigment epithelium also degenerates. Over time, the abnormal accumulation of this substance can damage the cells that are critical for clear central vision. As a result, people with this disorder often lose their central vision and may experience blurry or distorted vision, and loss is rarely symmetric. Scotomata appear, first with red light and then for green; finally, relative (or in more serious cases, absolute) scotomata occur with white light. Vitelliform macular dystrophy does not affect side (peripheral) vision or the ability to see at night.

Researchers have described two forms of vitelliform macular dystrophy with similar features. The early-onset form (known as Best disease) usually appears in childhood; however, the onset of symptoms and the severity of vision loss vary widely. The adult-onset form begins later, usually in middle age, and tends to cause relatively mild vision loss. The two forms of vitelliform macular dystrophy each have characteristic changes in the macula that can be detected during an eye examination.

Pseudoxanthoma elasticum (PXE), also known as Grönblad–Strandberg syndrome, is a genetic disease that causes fragmentation and mineralization of elastic fibers in some tissues. The most common problems arise in the skin and eyes, and later in blood vessels in the form of premature atherosclerosis. PXE is caused by autosomal recessive mutations in the "ABCC6" gene on the short arm of chromosome 16 (16p13.1).

Vitelliform macular dystrophy or vitelliform dystrophy is an irregular autosomal dominant eye disorder which can cause progressive vision loss. This disorder affects the retina, specifically cells in a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. The condition is characterized by yellow (or orange), slightly elevated, round structures similar to the yolk (Latin "vitellus") of an egg.