On this page, you will find information about a genetic change that was identified in a UDN participant. 

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Date of Report

Jun 08, 2017

Full Name

G protein subunit alpha o1

Chromosome 16 (16q13)


The GNAO1 gene codes for an alpha subunit of the guanine nucleotide-binding proteins (G proteins) (Strathmann et al., 1990).

Database Links

GeneCards: GC16P056231

Genetics Home Reference: GNAO1 gene

NCBI Gene: 2775

OMIM: 139311

UniProtKB/Swiss-Prot: P09471

Clinical Significance

Changes in the GNAO1 gene have been found in individuals with epileptic encephalopathy, early infantile, 17 (EIEE17).

A change in the GNAO1 gene was also identified in a UDN participant. The participant, a 15 year old female with weakness and stiffness in her limbs (spastic paraparesis), uncontrollable muscle contractions (dystonia), and slurred speech (dysarthria) was found to carry the following genetic change in the GNAO1 gene: c.662C>A/ p.A221D.

Gene GNAO1
Inheritance Pattern Autosomal dominant
Position Chr16:56370711
Transcript NM_020988
DNA Change c.662C>A
Protein Change p.A221D

Early in life, the patient had trouble meeting her developmental milestones (global developmental delay). She struggled with speech (expressive and receptive language delay) and did not walk until age 3.

At age 4, she started to have muscle weakness and spasms in her legs and arms (spastic paraparesis). She also began to have trouble with fine motor tasks and her movements and speech slowed. Her symptoms would get progressively worse as the day would go on. She was started on a trial of Sinemet, which helped relieve some of her symptoms. She does not have seizures.

Some of her other features include:

  • Mild intellectual disability
  • Uncontrollable muscle contractions (dystonia)
  • Abnormality of brain electrical activity (EEG abnormality)
  • Rigidity
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