PPP2R1A-Related Syndrome
PPP2R1A-related syndrome is also called PPP2R1A-related neurodevelopmental disorder or Houge-Janssens syndrome 2. For this webpage, we will be using the name PPP2R1A-related syndrome to encompass the wide range of variants observed in the people identified.
What is PPP2R1A-related syndrome?
PPP2R1A-related syndrome happens when there are changes in the PPP2R1A gene. These changes can keep the gene from working as it should.
Key Role
The PPP2R1A gene plays an important role in the development and function of brain cells. The gene is called PPP2R1A, and the protein is called protein phosphatase 2A (PP2AA).
Symptoms
Because the PPP2R1A gene is important in brain activity, many people who have PPP2R1A-related syndrome have:
- Global developmental delay
- Intellectual disability
- Seizures
- Speech and language delay
- Delayed walking
- Lower than average muscle tone
- Larger than average head size or small head size
- Attention deficit hyperactivity disorder also, called ADHD
- Self-harming or destructive behavior
- Autism
- Anxiety
- Brain changes seen on magnetic resonance imaging (MRI)
- Feeding issues
- Heart issues
What causes PPP2R1A-related syndrome?
PPP2R1A-related syndrome is a genetic condition, which means that it is caused by variants in genes. Our genes contain the instructions, or code, that tell our cells how to grow, develop, and work. Every child gets two copies of the PPP2R1A gene: one copy from their mother’s egg, and one copy from their father’s sperm. In most cases, parents pass on exact copies of the gene to their child. But the process of creating the egg or sperm is not perfect. A change in the genetic code can lead to physical issues, developmental issues, or both.
Sometimes a spontaneous variant happens in the sperm, egg or after fertilization. When a brand new genetic variant happens in the genetic code is called a ‘de novo’ genetic variant. The child is usually the first in the family to have the genetic variant.
De novo variants can take place in any gene. We all have some de novo variants, most of which don’t affect our health. But because PPP2R1A plays a key role in development, de novo variants in this gene can have a meaningful effect.
Research shows that PPP2R1A-related syndrome is often the result of a de novo variant in PPP2R1A. Many parents who have had their genes tested do not have the PPP2R1A genetic variant found in their child who has the syndrome. In some cases, PPP2R1A-related syndrome happens because the genetic variant was passed down from a parent.
Autosomal dominant conditions
PPP2R1A-related syndrome is an autosomal dominant genetic condition. This means that when a person has the one damaging variant in PPP2R1A they will likely have symptoms of PPP2R1A-related syndrome. For someone with an autosomal dominant genetic syndrome, every time they have a child there is a 50 percent chance they pass on the same genetic variant and a 50 percent chance they do not pass on the same genetic variant.
Autosomal Dominant Genetic Syndrome
Why does my child have a change in the PPP2R1A gene?
No parent causes their child’s PPP2R1A-related syndrome. We know this because no parent has any control over the gene changes that they do or do not pass on to their children. Please keep in mind that nothing a parent does before or during the pregnancy causes this to happen. The gene change takes place on its own and cannot be predicted or stopped.
What are the chances that other family members of future children will have PPP2R1A-related syndrome?
Each family is different. A geneticist or genetic counselor can give you advice on the chance that this will happen again in your family.
The risk of having another child who has PPP2R1A-related syndrome depends on the genes of both biological parents.
- If neither biological parent has the same genetic variant found in their child, the chance of having another child who has the syndrome is on average 1 percent. This 1 percent chance is higher than the chance of the general population. The increase in risk is due to the very unlikely chance that more of the mother’s egg cells or the father’s sperm cells carry the same genetic variant.
- If one biological parent has the same genetic variant found in their child, the chance of having another child who has the syndrome is 50 percent.
For a symptom-free brother or sister of someone who has PPP2R1A-related syndrome, the sibling’s risk of having a child who has PPP2R1A-related syndrome depends on the sibling’s genes and their parents’ genes.
- If neither parent has the same genetic variant causing PPP2R1A-related syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit PPP2R1A-related syndrome.
- If one biological parent has the same genetic variant causing PPP2R1A-related syndrome, the symptom-free sibling has a 50 percent chance of also having the same genetic variant. If the symptom-free sibling has the same genetic variant, their chance of having a child who has the genetic variant is 50 percent.
For a person who has PPP2R1A-related syndrome, the risk of having a child who has the syndrome is about 50 percent.
How many people have PPP2R1A-related syndrome?
As of 2024, at least 50 people with PPP2R1A-related syndrome have been identified in medical research.
Do people who have PPP2R1A-related syndrome look different?
People who have PPP2R1A-related syndrome may look different. Appearance can vary and can include some but not all of these features:
- Larger or smaller than average head size
- Longer face with a taller forehead
- Wide-set eyes
- Smaller than average opening of the eyelids
- A small nose with a noticeable nasal tip
- Thin upper lip
- Drooping eyelid
How is PPP2R1A-related syndrome treated?
Scientists and doctors have only just begun to study PPP2R1A-related syndrome. At this point, there are no medicines designed to treat the syndrome. A genetic diagnosis can help people decide on the best way to track the condition and manage therapies. Doctors can refer people to specialists for:
- Physical exams and brain studies
- Genetics consults
- Development and behavior studies
- Other issues, as needed
A developmental pediatrician, neurologist, or psychologist can follow progress over time and can help:
- Suggest the right therapies. This can include physical, occupational, speech, or behavioral therapy.
- Guide individualized education plans (IEPs).
Specialists advise that therapies for PPP2R1A-related syndrome should begin as early as possible, ideally before a child begins school.
If seizures happen, consult a neurologist. There are many types of seizures, and not all types are easy to spot. To learn more, you can refer to resources such as the Epilepsy Foundation’s website: epilepsy.com/…t-is-epilepsy/seizure-types
This section includes a summary of information from published articles on PPP2R1A-related syndrome. To learn more about the articles, see the Sources and references section of this guide.
Behavior and development concerns linked to PPP2R1A-related syndrome
Most people had intellectual disability, usually ranging from moderate to severe, and developmental delay, ranging from mild to profound. Most people had speech and language delay, with some people remaining non-verbal.
- 56 out of 57 people had intellectual disability (98 percent)
- 42 out of 42 people had developmental delay (100 percent)
- 39 out of 39 people had speech and language delay (100 percent)
Most people had delayed walking, and some people were unable to walk. Most people had low muscle tone, and some of those with low muscle tone had long-lasting or permanent low muscle tone.
- 28 out of 30 people had delayed walking (93 percent)
- 30 out of 36 people had motor delays (83 percent)
- 44 out of 50 people had low muscle tone or hypotonia (88 percent)
About one-half of people had seizures, which were often associated with moderate-severe intellectual disability. People with a small head size had an increased risk of developing seizures, and those who had seizures typically developed them in the first year of life. In a few people, seizures were multifocal and did not respond to medication. People with seizures were more likely to display behavioral issues like ADHD, anxiety, self-harm or destructive behavior, and autism. About two-thirds of people had brain changes seen on magnetic resonance imaging (MRI).
- 25 out of 50 people had seizures (50 percent)
- 18 out of 54 people had a large head size or macrocephaly (33 percent)
- 23 out of 54 people had a small head size or microcephaly (43 percent)
- 37 out of 55 people had corpus callosum hypoplasia (67 percent)
- 15 out of 38 people had an enlargement of the ventricles of the brain, also called ventriculomegaly (39 percent)
- 22 out of 27 people had behavior issues (81 percent)
Growth
Some people were shorter than average in height.
- 3 out of 37 people had short height (8 percent)
Medical and physical concerns linked to PPP2R1A-related syndrome
Other physical issues included: external ear formation issues; hearing loss; joint hypermobility; sideways curve of the spine, also called scoliosis; feeding difficulty; and heart issues.
- 11 out of 37 people had external ear formation issues (30 percent)
- 5 out of 38 people had hearing loss (13 percent)
- 14 out of 37 people had joint hypermobility (38 percent)
- 9 out of 37 people had scoliosis (24 percent)
- 23 out of 38 people had feeding difficulty (61 percent)
- 3 out of 37 people had persistent ductus arteriosus, an opening in the heart that usually goes away after birth (8 percent)
Where can I find support and resources?
PPP2R5D Foundation Website
Jordan’s Guardians Angels’ mission is to conduct research seeking answers to rare genetic mutations affecting children and adults, and assist and improve the quality of life for children and families.
Simons Searchlight
Simons Searchlight is an online international research program, building an ever growing natural history database, biorepository, and resource network of over 175 rare genetic neurodevelopmental disorders. By joining their community and sharing your experiences, you contribute to a growing database used by scientists worldwide to advance the understanding of your genetic condition. Through online surveys and optional blood sample collection, they gather valuable information to improve lives and drive scientific progress. Families like yours are the key to making meaningful progress. To register for Simons Searchlight, go to the Simons Searchlight website at www.simonssearchlight.org and click “Join Us.”
- Learn more about Simons Searchlight: www.simonssearchlight.org/frequently-asked-questions
- Simons Searchlight webpage with more information on PPP2R1A: www.simonssearchlight.org/research/what-we-study/ppp2r1a
- Simons Searchlight Community: https://www.facebook.com/groups/1095511794170880/
Sources and references
The content in this guide comes from published studies about PPP2R1A-related syndrome. Below you can find details about each study, as well as links to summaries or, in some cases, the full article.
- Douzgou S, Janssens V, & Houge G. PPP2R1A-Related Neurodevelopmental Disorder. 2022 May 12. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from: https://www.ncbi.nlm.nih.gov/books/NBK580243/
- Qian, Y., Jiang, Y., Wang, J., Li, G., Wu, B., Zhou, Y., Xu, X., & Wang, H. (2023). Novel variants of PPP2R1A in catalytic subunit binding domain and genotype-phenotype analysis in neurodevelopmentally delayed patients. Genes (Basel), 14(9), 1750. https://pubmed.ncbi.nlm.nih.gov/37761890/