What are the other Names for this Condition? (Also known as/Synonyms)

• Bilateral Generalised Polymicrogyria

What is Bilateral Generalized Polymicrogyria? (Definition/Background Information)

• Bilateral Generalized Polymicrogyria is a rare neurological disorder that affects the cerebral cortex (the outer surface of the brain)
  • Polymicrogyria is an abnormal pre-natal development of brain, which results in an increase in the number of brain folds or gyri
  • This is the most widespread form of polymicrogyria and typically affects the entire surface of the brain
• Signs and symptoms include severe intellectual disability, problems with movement, and seizures that are difficult or impossible to treat
• While the exact cause of Bilateral Generalized Polymicrogyria is not fully understood, it is thought to be due to improper brain development during embryonic growth. Most cases appear to follow an autosomal recessive pattern of inheritance
• Treatment is based on the signs and symptoms present in each person

(Source: Bilateral Generalized Polymicrogyria; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Bilateral Generalized Polymicrogyria? (Age and Sex Distribution)

• Bilateral Generalized Polymicrogyria is a rare congenital disorder of unknown incidence
• The presentation of symptoms may occur at birth
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Bilateral Generalized Polymicrogyria? (Predisposing Factors)

The risk factors for Bilateral Generalized Polymicrogyria may include:

• A family history of the condition
• Infections during pregnancy
• Oxygen deprivation to the fetus during gestation (intra-uterine ischemia)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Bilateral Generalized Polymicrogyria? (Etiology)

Presently, the exact genetic cause of Bilateral Generalized Polymicrogyria is not well-established.

• In addition to genetic factors, certain environmental factors may also lead to developmental abnormalities in the fetus
• These environmental factors may include infections in the mother during pregnancy and oxygen deprivation to the developing fetus
• When the condition runs in a family, it is reportedly transmitted in an autosomal recessive manner

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Bilateral Generalized Polymicrogyria?

The signs and symptoms of Bilateral Generalized Polymicrogyria may include:

• Muscle weakness/paralysis
• Developmental abnormalities
• Intellectual deficiency
• Seizures that are difficult to control with medication

How is Bilateral Generalized Polymicrogyria Diagnosed?

Bilateral Generalized Polymicrogyria is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Bilateral Generalized Polymicrogyria?

The complications of Bilateral Generalized Polymicrogyria may include:

• Difficulty with movement, which can be severe
• Severe intellectual deficiency
• Recurrent seizures
• Risk of falls and injury due to seizures

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Bilateral Generalized Polymicrogyria Treated?

There is no cure for Bilateral Generalized Polymicrogyria, since it is believed to be a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develops.

How can Bilateral Generalized Polymicrogyria be Prevented?

Bilateral Generalized Polymicrogyria may not be preventable.

• Taking precautions to prevent infections in the mother during pregnancy may help in minimizing the likelihood of Bilateral Generalized Polymicrogyria in the developing fetus
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Bilateral Generalized Polymicrogyria? (Outcomes/Resolutions)

• The prognosis of Bilateral Generalized Polymicrogyria is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Bilateral Generalized Polymicrogyria:

• Although polymicrogyria as a broad category of disorders is collectively believed to be fairly common, each individual type (such as Bilateral Generalized Polymicrogyria) is probably rare
• Unfortunately for the rare diseases, there's often not a calculated incidence or prevalence; there is no official method for tracking these conditions
• To our knowledge, the incidence and prevalence of Bilateral Generalized Polymicrogyria remains unknown

(Source: Bilateral Generalized Polymicrogyria; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/