What are the features of BBSOAS?
Features present at birth:
- Hypotonia (low muscle tone): 75%
- Oromotor dysfunction (swallowing problems): 60%
- Vision problems such as nystagmus and poor tracking
Features that arise over time:
- Vision impairment caused by optic atrophy
- Developmental delay/intellectual disability
- Seizures: 40%
- Repetitive behaviors: 40%
- Autism spectrum disorder: 35%
- Attention-deficit hyperactivity disorder: 20%
- Hearing impairment: 20%
Frequently Asked Questions
All of our cells hold DNA, the genetic material made up of a sequence of letters that provides instructions for the body. Our DNA is tightly packed together into structures called chromosomes. We get our chromosomes from our parents (23 from our mother and 23 from our father). Found on chromosomes are many genes, which function like recipes in a cookbook. Similar to a typo in a recipe, changes in a gene can cause changes in the body as well. These random changes are called mutations. NR2F1 is a gene located on chromosome 5 that is important for brain and eye development, and mutations in this gene cause BBSOAS features.
BBSOAS is diagnosed by a geneticist through either chromosome microarray, whole exome sequencing, or NR2F1 sequencing. Once a deletion or mutation in NR2F1 has been identified, parents can be tested to determine if the mutation was inherited or arose de novo. Most often, BBSOAS is caused by a de novo mutation, meaning the mutation occurred as a new event in the sperm or egg before the child was conceived, and neither parent has the mutation. However, in some cases, BBSOAS can be an inherited disorder. This means that at least one parent is affected, and if they pass down an abnormal copy of the gene to their child, the child will also have the disorder.
- A brain MRI, recommended at age three or older
- A full, dilated eye examination by an ophthalmologist every two years
- A full hearing evaluation every two years
- A comprehensive psychological evaluation for autism consisting of ADI-R and ADOS testing performed by a certified clinical psychologist
- A developmental assessment to identify areas of impairment and allow for early intervention
This depends on whether the NR2F1 mutation was inherited or de novo, which you will see in the results of the genetic testing. If neither parent is affected and the mutation occurred de novo, the parents have a <5% chance of having another child affected by an NR2F1 mutation. If a parent does have an NR2F1 mutation, then their chance of passing it to their children is 50%. This is because BBSOAS is considered “autosomal dominant,” which means that someone who receives a single copy of an abnormal NR2F1 gene from either parent may have this disorder.
- Introduce objects with bold colors and use simple pictures
- Reduce distractions and visual clutter (ex: place objects in front of an all-black background)
- Ensure your child is properly positioned to accommodate for central field loss
- Provide needed physical support (ex: hold up the child’s head)
- Use familiar and real objects rather than abstract objects to encourage visual attention
Is there a cure for BBSOAS?
Currently, there is no cure to treat BBSOAS. However, with early intervention and proper management, much can be done to improve the skill sets and quality of life of parents with BBSOAS. At present, this should include physical therapy, occupational therapy, and speech therapy, as well as ABA therapy if autism is present. There are also a variety of strategies that can be implemented to support children’s learning and development.