Infantile cerebellar retinal degeneration

Alternate names

Infantile cerebellar-retinal degeneration; ICRD

Definition

Infantile cerebellar retinal degeneration (ICRD) is a genetic condition present from birth (congenital) that involves the brain and eyes.

Cause

• ICRD is a genetic disorder caused by mutations in the ACO2 gene.
• This gene codes for a protein found in the mitochondria that is involved in the citric acid cycle, which is the process in which energy is created from the breakdown of the foods we eat.

Inheritance

Autosomal recessive inheritance, a 25% chance

ICRD is inherited in an autosomal recessive manner. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. There is nothing either parent can do, before or during a pregnancy, to cause a child to have this condition. People with ICRD inherit one mutation from each of their parents. The parents, who each have one mutation, are known as carriers. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:

• 25% chance to be affected
• 50% chance to be an unaffected carrier like each parent
• 25% chance to be unaffected and not a carrier

Signs and symptoms

The signs and symptoms of ICRD usually begin around 2-6 months of age. The main feature of this condition involve a decline of the ophthalmologic and nervous systems and may include:

• Developmental delay and intellectual disability
• Weakness (hypotonia) of the muscles in the chest and abdomen
• Slow, involuntary movement of certain muscles in the body (athetosis)
• Seizures
• Head bobbing
• Retinal degeneration
• Eye abnormalities such as strabismus and nystagmus
• Failure to thrive (slow or inadequate weight gain)
• Hearing and vision loss
• Absence or loss of reflexes

Diagnosis

• On brain imaging such as MRI, findings may include worsening cerebellar atrophy as well as agenesis of the corpus callosum.
• Additionally, the head of individuals with ICRD may not grow at the same rate as the rest of the body, so it appears to be getting smaller than the rest of the body (progressive microcephaly).

Treatment

While there is still no cure for this condition, treatment options will depend on the type and severity of symptoms.

NIH genetic and rare disease info

• NIH info on Infantile cerebellar retinal degeneration

Infantile cerebellar retinal degeneration is a rare disease.

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