CIC mutations

Overview

CIC (capicua) is a protein-coding gene involved in the normal development of an organism. It also plays a role in tumor suppression.

Individuals who are born with a mutation in CIC have been found to have a neurodevelopmental disorder. The clinical features of CIC mutations include developmental delay/intellectual disability, seizures, attention deficit/hyperactivity disorder (ADHD), autism spectrum disorder, expressive language delay and speech and/or motor impairments.

Diagnosis

Mutations in CIC are point mutations. These mutations are diagnosed through clinical sequencing of DNA. The inheritance pattern of the disease caused by CIC mutations is autosomal dominant, which means that a single copy of an abnormal CIC gene is sufficient for a person to have this disorder. For someone who has a CIC mutation, their chance of passing it to their children is 50%.

CIC mutations can be de novo, meaning that a mutation arose spontaneously during the development of the parents' sperm and egg cells. With de novo mutations, the mother and father would be unaffected by the mutation.

Sometimes the mother or father can carry a CIC mutation in their germ cells (eggs or sperms) but not in other cells of the body, known as gonadal mosaicism. Mosaicism, stemming from mosaic, in when someone has two genetically different cells. Sometimes the mother or father can carry the mutation in a small proportion of the cells throughout the body. This is called low-grade mosaicism. CIC mutations can come from gonadal mosaicism or low-grade mosaicism and be passed on to the next generation.

Management

The following tests and therapies may be helpful for patients who have been found to have a mutation in the CIC gene.

Clinical Exams/Tests:

1) Formal cognitive and behavioral testing by a licensed pediatric psychiatrist

2) Comprehensive psychological evaluation for autism: ADI-R and ADOS testing performed by a certified clinical psychologist

3) A full assessment by a speech pathologist

4) An EEG test to test for abnormal electric activity that could cause/predispose seizures

5) A brain MRI

Other Therapies

1) Physical and occupational therapy

2) Speech therapy

Additional Resources