Porencephaly Fast Facts

Porencephaly is a disorder in which fluid-filled cavities or cysts form on the surface of the brain.

The condition usually results from an event such as an infection or a stroke, but in some cases, it can result from an inherited genetic disorder.

Symptoms of porencephaly may include developmental delays, speech problems, seizures, and intellectual impairments.

The long-term outlook for children with porencephaly varies widely from case to case.

United Brain Association

The long-term outlook for children with porencephaly varies widely from case to case.

What is Porencephaly?

Porencephaly is a neurological disorder in which cysts or spaces form on the surface of the brain. These spaces are sometimes filled with cerebrospinal fluid (CSF), a liquid that normally surrounds, protects, and nourishes the brain and central nervous system.

The effects of porencephaly vary widely depending on the size and location of the cysts. In some cases, children with the disorder experience mild symptoms and no intellectual impairments. However, in severe cases, porencephaly can cause profound symptoms and disabilities, and complications of the condition can be life-threatening.

Symptoms of Porencephaly

Common symptoms of porencephaly include:

  • Slow growth
  • Developmental delays
  • Weak muscle tone
  • Seizures
  • Atypically small or large head size
  • Speech impairments
  • Accumulation of fluid in the brain (hydrocephalus)
  • Paralysis
  • Stiffening of muscles
  • Intellectual disability

What Causes Porencephaly?

In most cases, porencephaly is caused by an event or condition that damages the cerebral hemispheres, the largest parts of the brain. Infections and conditions that cause bleeding or lack of blood flow in the brain are thought to be the primary causes of this kind of brain tissue damage. The cysts or fluid-filled spaces form in reaction to the injury.

Potential causes include:

  • Infection of the baby just before or just after birth
  • Loss of blood flow to the baby close to the time of birth
  • Trauma or injury during birth
  • Drug or alcohol abuse by the mother during pregnancy
  • Infection of the mother during pregnancy
  • Abdominal trauma or injury to the mother during pregnancy
  • Disorders that can cause bleeding in newborns such as neonatal alloimmune thrombocytopenia and von Willebrand’s disease
  • Use of certain blood thinners by the mother during pregnancy

In rare cases, the medical diagnostic procedures amniocentesis and chorionic villus sampling have been associated with porencephaly.

Is Porencephaly Hereditary?

Porencephaly is usually not inherited. However, in a minority of cases, the disorder is associated with an abnormal change (mutation) in the COL4A1 gene. The mutation causes weakness in the brain’s blood vessels which may, in turn, lead to bleeding in the brain that causes porencephaly to develop.

This type of the disorder is called familial porencephaly, and it has some distinct characteristics. The cysts or fluid-filled spaces typically develop on only one side of the brain. Children with this type of the disorder often experience paralysis on one side of their body during infancy (infantile hemiplegia).

Familial porencephaly is inherited in an autosomal dominant pattern. This means that a child need only inherit one disorder-causing mutation from either parent to develop the condition. If one parent carries the mutation, they have a 50 percent chance of having an affected child with each pregnancy.

How Is Porencephaly Detected?

When it develops before birth, porencephaly may be detected via imaging exams such as ultrasound, magnetic resonance imaging (MRI), or computerized tomography (CT). Ultrasound exams are most likely to catch the disorder’s characteristic features after the 30th week of pregnancy.

How Is Porencephaly Diagnosed?

Porencephaly is usually diagnosed in infancy, before the baby is one year old, when symptoms of the disorder become apparent. The diagnostic process may include:

  • Assessment of the child’s medical and family history
  • Physical and neurological exams
  • Imaging scans such as MRI, CT, or ultrasound to look for the cysts or spaces associated with the condition
  • Genetic testing to look for the COL4A1 gene mutations associated with familial porencephaly


How Is Porencephaly Treated?

Prompt treatment of porencephaly may be able to prevent or lessen the long-term impact of the disorder. Common treatments and therapies include:

  • Surgery to place a thin tube (called a shunt) in the brain to drain fluid from the cysts or cavities
  • Anti-seizure medications
  • Physical therapy
  • Speech therapy

How Does Porencephaly Progress?

The long-term impact of porencephaly varies according to the severity of the disorder, including the size of the cysts and the part of the brain in which they’re located. In mild cases, children may develop normally and experience few or no long-term complications. However, in severe cases, neurological symptoms can be serious, and complications of the disorder can be life-threatening.

Potential effects of porencephaly include:

  • Speech impairments or no speech development
  • Epilepsy
  • Mobility problems associated with rigid or shrinking muscles (contractures)
  • Paralysis
  • Fluid accumulation in the brain (hydrocephalus) that causes neurological symptoms
  • Intellectual disability

How Is Porencephaly Prevented?

Avoidance of risk factors during pregnancy is the best way to decrease the risk of porencephaly:

  • Get vaccinations as recommended by your doctor and take steps to avoid infections.
  • Don’t use drugs or alcohol during pregnancy.
  • Get good prenatal care to lessen the chance of birth complications.
  • Take safety precautions to avoid injury or trauma during pregnancy.

Parents with a family history of the disorder or who have had another child with familial porencephaly are advised to consult a genetic counselor to assess their risk if they plan to have another child.

Porencephaly Caregiver Tips

  • Be an advocate for your child. Learn all you can about porencephaly so you can understand the challenges your child faces, and be prepared to educate others about what they can do to help and support you and your child.
  • Remember that you’re not alone. Porencephaly is rare, and you may feel as if you’re the only one who knows what it’s like to live with the disorder. Connections with others who are going through the same thing can help. The Child Neurology Foundation maintains educational resources, access to one-to-one peer networks, and links to support groups.

Some people with porencephaly also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with porencephaly:

Porencephaly Brain Science

Mutations in the COL4A1 gene cause familial porencephaly. This gene carries instructions for making one part of type IV collagen, a protein vital in creating membranes that help strengthen and hold together tissues throughout the body. The COL4A1 mutations associated with porencephaly interfere with the normal production of type IV collagen, and, as a result, tissues are weaker than usual.

In familial porencephaly, weakened blood-vessel tissue in the brain can break down when subjected to trauma such as inflammation or injury during birth. This can cause bleeding in the brain and damage to brain tissue, and the fluid-filled cavities of porencephaly develop as a result.

Porencephaly Research

Title: Long-term Outcome of Children With Neonatal Intra-Ventricular or Intra-Cranial Hemorrhage (NEONATAL ICH)

Stage: Recruiting

Sub-investigator: Nechama Sharon, MD

Laniado Hospital

Netanya, Israel

Intraventricular hemorrhage (IVH) is the most commonly recognized cerebral lesion on ultrasound in extremely preterm infants. Papile classification is frequently used to grade the severity of IVH. Grade III-IV IVH and other lesions noted on ultrasound, including periventricular leukomalacia (pvl) porencephaly, and ventriculomegaly are well documented to be associated with adverse neurodevelopmental outcomes.

However, the true impact of lower-grade IVH on the neurodevelopment of these extremely preterm infants has not been well described.

Also, the neurodevelopmental outcome for neonatal non-traumatic Intra-cranial Hemorrhage (ICH) is not well established.

This study aims to look retrospectively at babies with neonatal IVH or ICH and follow their radiological, cognitive, motor, and functional outcomes.

The study will focus on postnatal files and images performed as part of the child’s follow-up during hospitalization and after discharge.

The study will be performed as a retrospective chart review with keywords: IVH, ICH of babies discharged from Laniado Hospital Neonatal care service or ICU, or being followed in the pediatric neurosurgical clinic and prematurity/neonatology clinic of the hospital.

All charts of such children will be included to review clinical and radiological available data.

Registration of Clinical, Radiological data as presented or submitted by the parents on Neurosurgical neonatology and Neurological Followups will be performed by PI or CI and coded in the data anonymously.

Follow-up will be performed as clinically indicated without the addition of any specific studies due to the research.


Title: Study of Abnormal Blood Clotting in Children With Stroke

Stage: Completed

National Institutes of Health Clinical Center

Bethesda, MD

Effective treatment and prevention strategies for childhood stroke and porencephaly can only be developed once the causes are understood. There is increasing evidence that inherited and acquired coagulation abnormalities alone or combined with environmental factors predispose to arterial and venous thrombosis. Inherited abnormalities of factor V Leiden, prothrombin, protein C, protein S, and antithrombin III may account for many of these thromboses. At present, there is little information on the existing distribution of these coagulation anomalies in children with thrombosis. Recent reports also suggest that these clotting abnormalities may be responsible for some instances of intracranial hemorrhage, porencephaly, cerebral palsy, and fetal death.

This study will measure the frequency of several coagulation factor abnormalities (factor V Leiden, prothrombin 20210A, protein C, protein S, antithrombin III, and antiphospholipid antibodies) in children with a history of porencephaly and stroke and will compare these to the prevalence of these mutations in population controls and family members. Researchers will also describe the exogenous conditions that, in concert with these coagulation factors, may have led to thrombosis in these children.


Title: COL4A1 Gene-Related Cerebra-retinal Angiopathy (COL4A1)

Stage: Completed

Principal investigator: Hugues Chabriat, MD,PhD

Hôpital Lariboisiere Neurology Department

Paris, France

This prospective multicenter cohort study aims to define the clinical, radiological, and mutational spectrum of the disease related to the COL4A1 gene.

Clinical brain MRI-MRA and genetic testing (COL4A1 mutation screening) will be conducted for each included patient or asymptomatic relatives. Thirteen French investigating centers will participate in the study.

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