User:Bhwang8/Porencephaly

Porencephaly is an extremely rare cephalic disorder involving encephalomalacia and neurological disorder of the central nervous system characterized with cysts or cavities within the cerebral hemisphere. , Porencephaly was termed by Heschl in 1859 to describe a cavity in the human brain. . The cysts and cavities are usually the remnants of destructive lesions but can also be the result of abnormal development. Developmental abnormalities, direct damage or tramaua, inflammation, or hemorrhage can cause cystic brain lesions. The cysts and cavities result in a wide range of physiological, physical, and neurological symptoms. . Depending on the patient, this disorder may cause only minor neurological problems, without any disruption on intelligence, while others may be severely disabled or may face death before the second decade of their lives. However, the disorder is far more common within infants, but porencephaly can occur in both before or after birth.

Signs and Symptoms
Patients with porencephaly display a variety of symptoms having anywhere from little to severe effect on the patient. Depending on the severity of the disorder, patients with severe case of porencephaly suffered from epileptic seizures and severe developmental delays, whereas patients with a mild case of porencephaly showed little to no seizures and good neurodevelopment. Infants with extensive defects show symptoms of the disorder shortly after birth, and the diagnosis is usually made before the age of 1. ,

The following text lists out common signs and symptoms of porencephaly in affected individuals. ,, ,
 * Degenerative or non-degenerative cavities or cysts
 * Delayed growth and development
 * Spastic paresis and contractures
 * Hypotonia
 * Epileptic seizures and epilepsy
 * Macrocephaly
 * Microcephaly
 * Hemiplegia
 * Tetraplegia
 * Intellectual and cognitive disability
 * Poor or absent speech development
 * Hydrocephalus
 * Mental retardation
 * Poor motor control, abnormal movements of appendages
 * Cerebral palsy
 * Blood vascular diseases such as intracerebral hemorrhage and cerebral infarction.
 * Cerebral white-matter lesions

Etiology
Porencephaly is a rare disorder that has not received a high level of attention. The exact prevalence of porencephaly is not known; however, it has been reported that 6.8% of patients with cerebral palsy or in 68% of patients with epilepsy and congenital vascular hemiparesis have porencephaly. Porencephaly most likely has a number of different, often unknown causes, including absence of brain development and destruction of brain tissue. However with limited research, the most commonly regarded cause of porencephaly is disturbances in blood circulation ultimately leading to brain damage. However, a number of different and multiple factors such as abnormal brain development or damage to the brain tissue affect the development of porencephaly.

Based on current research, porencephalic cysts are developed due to restriction of oxygen and blood supply to the brain disuse leading to internal bleeding and cerebral degeneration. . Monozygous twinning, maternal cardiac arrest or trauma during pregnancy, abdominal trauma, deficient protein C anticoagulant pathway, pathogenic infection, accidents, abnormal brain development during birth, vascular thrombosis, hemorrhage, brain contusion, cerebral degeneration, multifocal cerebrovascular insufficiency, systemic vascular insufficiency, placental bleeding, maternal toxemia,hypoxia, vascular occlusion, cystic preiventricular leukomalacia, cerebral atrophy, chronic lung disease, steroids for chronic lund disease, male gender, endotoxins, prenatal and postnatal encephalitis and meningitis, and drug abuse of mother are a few risk factors for developing porencephaly. ,, ,

Cysts or cavities can occur anywhere within the brain and the locations of these cysts depend highly on the patient. Cysts can develop in the frontal lobe, parietal lobe, forebrain, hindbrain, temporal lobe, or virtually anywhere in the cerebral hemisphere. ,

Genetics
From recent studies, de novo and inherited mutations in the gene COL4A1, suggesting genetic predisposition within the family, that encodes type IV collagen α1 chain has shown to be associated with and present in patients with porencephaly. COL4A1 mutation causes a variety of phenotypes, including porencephaly, infantile hemiplegia, and cerebral small vessel diseases involving both stroke and infarction. Abnormal gene expression of COL4A1 can contribute to the development of porencephaly. COL4A1 gene expresses a type IV collagen (basement protein) that is present in all tissue and is extremely important for the structural stability of vascular basement membranes. The COL4A1 protein provides a strong layer around blood vessels. The mutation can weaken the blood vessels within the brain, elevating the probability of a hemorrhage, and eventually promoting internal bleeding then leading to porencephaly during neurodevelopment of infantile stage. Therefore, the formation of cavities can be a result of hemorrhages which promotes cerebral degeneration. In a mouse model, mouse with COL4A1 mutations displayed cerebral hemorrhage, porencephaly, and abnormal development of vascular basement membranes, such as uneven edges, inconsistent shapes, and highly variable thickness. Purposely causing a mutation in the COL4A1 gene caused several mouse to develop cerebral hemorrhage and porencephaly-liked diseases. Though, there is no direct correlation between mutations of the COL4A1 gene, it appears it has an influential effect on the development of porencephaly. , ,

Another genetic mutation, Factor V G1691A mutation, has been reported to show possible association to the development of porencephaly. A mutation in Factor V G1691A increases the risk of thrombosis, blood clots, in neonates, infants, and children. Therefore, 76 porencephalic and 76 health infants were investigated for factor V G1691 A mutation along with other different prothrombotic risk factors. The results indicated that there was higher prevalence of the factor V G1691 A mutation in the porencephalic patient group. The prediction that childhood porencephaly is caused by hypercoagulable state, a condition where one has a higher chance of developing blood clots, was supported by the significance of the factor V G1691 A mutation. Also, pregnant women in hypercoagulable state can cause the fetus to have the same risks, therefore possibly causing fetal loss, brain damage, lesions, and infections that lead to porencephaly. However, other different prothrombotic risk factors individually did not reach statistical significant to link it to the development of porencephaly, but a combination of multiple prothrombotic risk factors in the porencephaly group was significant. Overall, factor V G1691A mutation has been linked to the development of porencephaly. However, this one mutation is not the cause of porencephaly, and whether further prothrombiotic risk factors are associated with porencephaly still remains an open question.

Diagnostics
The presence of porencephalic cysts or cavities can be detected using trans-illumination of the skull of infant patients. Porencephaly is usually diagnosed clinically using the patient and families history, clinical observations, or based on the presence of certain characteristic neurological and physiological features of porencephaly. Advanced medical imaging with computed tomography (CT), magnetic resonance imaging (MRI), or with ultrasonography can be used as a method to exclude other possible neurological disorders. The diagnosis can be made antenatally with ultrasound. Other assessments include memory, speech, or intellect testing to help further determine the exact diagnose of the disorder.

Treatments
Currently, there is no cure for porencephaly because of the limited resources and knowledge about the neurological disorder. However, several treatment options are available. Treatment may include physical therapy, rehabilitation, medication for seizures or epilepsy, shunt, or neurosurgery (removal of the cyst). According to the location, extent of the lesion, size of cavities, and severity of the disorder, combinations of treatment methods are imposed. In porencephaly patients, patients achieved good seizure control with appropriate drug therapy including valproate, carbamazepine, and clobazam. , Also, antiepileptic drugs served as another positive method of treatment.

Prognosis
The severity of the symptoms associated with porencephaly varies significantly across the population of those affected depending on the location of the cyst and damage of the brain. For some patients with porencephaly, only minor neurological problems may develop, and those patients can live normal lives. Therefore, based on the level of severity, self-care is possible, but for the severe cases life-long care will be necessary. For those that have severe disability, early diagnosis, medication, participation in rehabilitation related to fine-motor control skills and communication, speech, therapies can significantly improve overall the symptoms and ability of the patient with porencephaly to live a normal life. Infants with porencephaly that survive, with proper treatment, can display proper communication skills, movement, and live a normal life.

Research
Under the Federal Government, the National Institute of Neurological Disorders and Stroke and National Institute of Health are involved in conducting and supporting research related to normal and abnormal brain and nervous system development. Information gained from the research are used to develop understanding of the mechanism of porencephaly and used to offer new methods of treatment and prevention for developmental brain disorders such as porencephaly.