SNP Shot: Genomic Insights

Costeff syndrome is a genetic disorder affecting vision, development, and movement. A key feature is vision loss due to the breakdown (atrophy) of the optic nerves, which transmit visual signals to the brain. This optic nerve atrophy usually starts in infancy or early childhood, leading to progressive vision impairment. Some individuals may also experience involuntary eye movements (nystagmus) or misaligned eyes (strabismus).

Individuals with Costeff syndrome often experience delays in motor skill development, such as learning to walk. Speech difficulties (dysarthria) may also be present. While some affected individuals have mild to moderate intellectual disability, many maintain normal cognitive abilities.

Movement problems typically emerge in late childhood and include muscle stiffness (spasticity), poor coordination (ataxia), and involuntary jerking motions (choreiform movements). These movement issues can be severe enough to necessitate the use of a wheelchair.

A characteristic of Costeff syndrome is elevated levels of 3-methylglutaconic acid in the urine (3-methylglutaconic aciduria). However, the level of this acid does not correlate with the severity of symptoms. Costeff syndrome is classified within a group of metabolic disorders identifiable by 3-methylglutaconic aciduria. Elevated levels of 3-methylglutaric acid are also found in the urine of individuals with Costeff syndrome.

Inheritance:

Costeff syndrome follows an autosomal recessive inheritance pattern. This means that an individual must inherit two mutated copies of the responsible gene, one from each parent, to develop the condition. The parents, who each carry only one copy of the mutated gene, are typically asymptomatic.