Infantile cerebellar retinal degeneration

Title

Other Names:

Infantile cerebellar-retinal degeneration; ICRD

Categories:

Congenital and Genetic Diseases; Eye diseases; Nervous System Diseases

Summary Summary

Infantile cerebellar retinal degeneration (ICRD) is a genetic condition present from birth (congenital) that involves the brain and eyes.^[1]^[2] Individuals with this condition usually develop symptoms around six months of age including developmental delays, low muscle tone (hypotonia), and seizures. Other symptoms may include head bobbing, abnormal muscle twitching and movement, and loss of brain cells in the main part of the brain called the cerebellum. Eye findings in individuals with this condition may include retinal degeneration (weakening of the layer of tissue in the back of the eye that senses light), strabismus (crossed eyes), and nystagmus (fast, uncontrollable movements of the eyes).^[1]^[2]^[3] ICRD is caused by mutations in the ACO2 gene and is inherited in an autosomal recessive manner.^[4] While there is still no cure for this condition, treatment options will depend on the type and severity of symptoms.

Last updated: 4/26/2017

Symptoms 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:^[1]^[4]

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

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).^[1]^[4]

Last updated: 4/26/2017

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms	Other Names	Learn More: HPO ID
5%-29% of people have these symptoms
Sensorineural hearing impairment		0000407
Percent of people who have these symptoms is not available through HPO
Areflexia	Absent tendon reflexes	0001284
Ataxia		0001251
Athetosis	Involuntary writhing movements in fingers, hands, toes, and feet	0002305
Autosomal recessive inheritance		0000007
Cerebellar atrophy	Degeneration of cerebellum	0001272
Cerebral cortical atrophy	Decrease in size of the outer layer of the brain due to loss of brain cells	0002120
Demyelinating peripheral neuropathy		0007108
Failure to thrive	Faltering weight Weight faltering [ more ]	0001508
Generalized hypotonia	Decreased muscle tone Low muscle tone [ more ]	0001290
Hypoplasia of the corpus callosum	Underdevelopment of part of brain called corpus callosum	0002079
Hyporeflexia	Decreased reflex response Decreased reflexes [ more ]	0001265
Infantile onset	Onset in first year of life Onset in infancy [ more ]	0003593
Intellectual disability, severe	Early and severe mental retardation Mental retardation, severe Severe mental retardation [ more ]	0010864
Nystagmus	Involuntary, rapid, rhythmic eye movements	0000639
Optic atrophy		0000648
Progressive microcephaly	Progressively abnormally small cranium Progressively abnormally small skull [ more ]	0000253
Retinal dystrophy	Breakdown of light-sensitive cells in back of eye	0000556
Seizure		0001250
Severe global developmental delay		0011344
Strabismus	Cross-eyed Squint Squint eyes [ more ]	0000486

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Do you have more information about symptoms of this disease? We want to hear from you.

Last updated: 2/1/2021

Do you have updated information on this disease? We want to hear from you.

Cause 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.^[5]

Last updated: 4/26/2017

Inheritance Inheritance

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

Last updated: 4/26/2017

Diagnosis Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Find a Specialist Find a Specialist

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from MedlinePlus Genetics.

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

The University of Arizona Health Sciences Hereditary Ocular Disease Database offers information on Infantile cerebellar retinal degeneration

In-Depth Information

Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

GARD Answers GARD Answers

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

Have a question? Contact a GARD Information Specialist.

References References

Spiegel R, Pines O, Ta-Shma A, et al. Infantile Cerebellar-Retinal Degeneration Associated with a Mutation in Mitochondrial Aconitase, ACO2. American Journal of Human Genetics. March 9, 2012; 90(3):518-523. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3309186/.
Infantile Cerebellar-Retinal Degeneration. The University of Arizona Health Sciences Hereditary Ocular Disease Database. http://disorders.eyes.arizona.edu/disorders/infantile-cerebellar-retinal-degeneration. Accessed 4/26/2017.
Bird TD. Hereditary Ataxia Overview. GeneReviews. November 3, 2016; https://www.ncbi.nlm.nih.gov/books/NBK1138/.
Kniffen CL. Infantile Cerebellar-Retinal Degeneration; ICRD. Online Mendelian Inheritance in Man (OMIM). 4/2/2015; http://omim.org/entry/614559.
ACO2 aconitase 2 [ Homo sapiens (human) ]. National Center for Biotechnology Information (NCBI). April 20, 2017; https://www.ncbi.nlm.nih.gov/gene/50.