OPA3 Gene

Costeff syndrome is an inherited condition characterized by vision loss, delayed development, and movement problems. Vision loss is primarily caused by degeneration (atrophy) of the optic nerves, which carry information from the eyes to the brain. This optic nerve atrophy often begins in infancy or early childhood and results in vision impairment that worsens over time. Some affected individuals have rapid and involuntary eye movements (nystagmus) or eyes that do not look in the same direction (strabismus).

Development of motor skills, such as walking, is often delayed in people with Costeff syndrome. Affected individuals may also have speech difficulties (dysarthria). While some people with Costeff syndrome have mild to moderate intellectual disability, many have normal intelligence.

Movement problems in people with Costeff syndrome develop in late childhood and include muscle stiffness (spasticity), impaired muscle coordination (ataxia), and involuntary jerking movements (choreiform movements). As a result of these movement difficulties, individuals with Costeff syndrome may require wheelchair assistance.

Costeff syndrome is associated with increased levels of a substance called 3-methylglutaconic acid in the urine (3-methylglutaconic aciduria). The amount of this substance does not appear to influence the signs and symptoms of the condition. Costeff syndrome is one of a group of metabolic disorders that can be diagnosed by the presence of 3-methylglutaconic aciduria. People with Costeff syndrome also have high levels of another acid called 3-methylglutaric acid in their urine.

Autosomal dominant optic atrophy and cataract is an eye disorder that is characterized by impaired vision. Most affected individuals have decreased sharpness of vision (visual acuity) from birth, while others begin to experience vision problems in early childhood or later. In affected individuals, both eyes are usually affected equally. However, the severity of the vision loss varies widely, even among affected members of the same family, ranging from nearly normal vision to complete blindness.

Several abnormalities contribute to impaired vision in people with autosomal dominant optic atrophy and cataract. In the early stages of the condition, affected individuals experience a progressive loss of certain cells within the retina, which is a specialized light-sensitive tissue that lines the back of the eye. The loss of these cells (known as retinal ganglion cells) is followed by the degeneration (atrophy) of the nerves that relay visual information from the eyes to the brain (optic nerves), which contributes to vision loss. Atrophy of these nerves causes an abnormally pale appearance (pallor) of the optic nerves, which can be seen only during an eye examination. Most people with this disorder also have clouding of the lenses of the eyes (cataracts). This eye abnormality can develop anytime but typically appears in childhood. Other common eye problems in autosomal dominant optic atrophy and cataract include involuntary movements of the eyes (nystagmus), or problems with color vision (color vision deficiency) that make it difficult or impossible to distinguish between shades of blue and green.

Some people with autosomal dominant optic atrophy and cataract develop disturbances in the function of other nerves (neuropathy) besides the optic nerves. These disturbances can lead to problems with balance and coordination (cerebellar ataxia), an unsteady style of walking (gait), prickling or tingling sensations (paresthesias) in the arms and legs, progressive muscle stiffness (spasticity), or rhythmic shaking (tremors). In some cases, affected individuals have hearing loss caused by abnormalities of the inner ear (sensorineural deafness).