Once the diagnosis of polymicrogyria has been established in an individual, the following approach can be used for discussion of prognosis:

A pregnancy history should be sought, with particular regard to infections, trauma, multiple gestations, and other documented problems. Screening for the common congenital infections associated with polymicrogyria with standard TORCH testing may be appropriate. Other specific tests targeting individual neurometabolic disorders can be obtained if clinically suggested.

The following may help in determining a genetic etiology:

Family history

It is important to ask for the presence of neurologic problems in family members, including seizures, cognitive delay, motor impairment, pseudobulbar signs, and focal weakness because many affected family members, particularly those who are older, may not have had MRI performed, even if these problems came to medical attention. In addition, although most individuals with polymicrogyria do present with neurologic difficulties in infancy, childhood, or adulthood, those with mild forms may have no obvious deficit or only minor manifestations, such as a simple lisp or isolated learning disability. Therefore, if a familial polymicrogyria syndrome is suspected, it may be reasonable to perform MRI on relatives who are asymptomatic or have what appear to be minor findings. The presence of consanguinity in a child's parents may suggest an autosomal recessive familial polymicrogyria syndrome.

Physical examination

A general physical examination of the proband may identify associated craniofacial, musculoskeletal, or visceral malformations that could indicate a particular syndrome. Neurologic examination should assess cognitive and mental abilities, cranial nerve function, motor function, deep tendon reflexes, sensory function, coordination, and gait (if appropriate).

Genetic testing

Parents of a proband

- The parents of an affected individual are obligate heterozygotes and therefore carry one mutant allele.

- Heterozygotes (carriers) are asymptomatic.

Sibs of a proband

- At conception, each sibling of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.

- Once an at-risk sibling is known to be unaffected, the risk of his/her being a carrier is 2/3.

- Heterozygotes (carriers) are asymptomatic.

Offspring of a proband

- Offspring of a proband are obligate heterozygotes and will therefore carry one mutant allele.

- In populations with a high rate of consanguinity, the offspring of a person with GPR56-related BFPP and a reproductive partner who is a carrier of GPR56-related BFPP have a 50% chance of inheriting two GPR56 disease-causing alleles and having BFPP and a 50% chance of being carriers.

Other family members of a proband.

- Each sibling of the proband's parents is at a 50% risk of being a carrier

Microlissencephaly can be diagnosed by prenatal MRI. MRI is better than ultrasound when it comes to detecting microlissencephaly or MSGP prenatally.

The ideal time for proper prenatal diagnosis is between the 34th and 35th gestational week which is the time when the secondary gyration normally terminates. In microlissencephaly cases, the primary sulci would be unusually wide and flat while secondary sulci would be missing.

At birth, lissencephaly with a head circumference of less than minus three standard deviations (< –3 SD) is considered microlissencephaly.

Although genetic diagnosis in patients with MLIS is challenging, exome sequencing has been suggested to be a powerful diagnostic tool.

Microlissencephaly is considered a more severe form than microcephaly with simplified gyral pattern. Microlissencephaly is characterized by a smooth cortical surface (absent sulci and gyri) with a thickened cortex (> 3 mm) and is usually associated with other congenital anomalies. Microcephaly with a simplified gyral pattern has too few sulci and normal cortical thickness (3 mm) and is usually an isolated anomaly.

There is no cure for this condition. Treatment is supportive and varies depending on how symptoms present and their severity. Some degree of developmental delay is expected in almost all cases of M-CM, so evaluation for early intervention or special education programs is appropriate. Rare cases have been reported with no discernible delay in academic or school abilities.

Physical therapy and orthopedic bracing can help young children with gross motor development. Occupational therapy or speech therapy may also assist with developmental delays. Attention from an orthopedic surgeon may be required for leg length discrepancy due to hemihyperplasia.

Children with hemihyperplasia are thought to have an elevated risk for certain types of cancers. Recently published management guidelines recommend regular abdominal ultrasounds up to age eight to detect Wilms' tumor. AFP testing to detect liver cancer is not recommended as there have been no reported cases of hepatoblastoma in M-CM patients.

Congenital abnormalities in the brain and progressive brain overgrowth can result in a variety of neurological problems that may require intervention. These include hydrocephalus, cerebellar tonsillar herniation (Chiari I), seizures and syringomyelia. These complications are not usually congenital, they develop over time often presenting complications in late infancy or early childhood, though they can become problems even later. Baseline brain and spinal cord MRI imaging with repeat scans at regular intervals is often prescribed to monitor the changes that result from progressive brain overgrowth.

Assessment of cardiac health with echocardiogram and EKG may be prescribed and arrhythmias or abnormalities may require surgical treatment.

Techniques used to diagnose this disorder are fluorescence in situ hybridization (FISH) and microarrays. FISH uses fluorescent dyes to visualize sections under a microscope, but some changes are too small to see. Microarray comparative genomic hybridization (array CGH) shows changes in small amounts DNA on chromosomes.

Treatment of Aicardi syndrome primarily involves management of seizures and early/continuing intervention programs for developmental delays.

Additional comorbidities and complications sometimes seen with Aicardi syndrome include porencephalic cysts and hydrocephalus, and gastro-intestinal problems. Treatment for porencephalic cysts and/or hydrocephalus is often via a shunt or endoscopic of the cysts, though some require no treatment. Placement of a feeding tube, fundoplication, and surgeries to correct hernias or other gastrointestinal structural problems are sometimes used to treat gastro-intestinal issues.

Amniotic band syndrome is considered an accidental event and it does not appear to be genetic or hereditary, so the likelihood of it occurring in another pregnancy is remote. The cause of amnion tearing is unknown and as such there are no known preventative measures.

The prognosis for children with NMDs varies depending on the specific disorder and the degree of brain abnormality and subsequent neurological signs and symptoms.

Aicardi syndrome is typically characterized by the following triad of features - however, one of the "classic" features being missing does not preclude a diagnosis of Aicardi Syndrome, if other supporting features are present.

1. Partial or complete absence of the corpus callosum in the brain (agenesis of the corpus callosum);

2. Eye abnormalities known as "lacunae" of the retina that are quite specific to this disorder; [optic nerve coloboma]]; and

3. The development in infancy of seizures that are called infantile spasms.

Other types of defects of the brain such as microcephaly, polymicrogyria, porencephalic cysts and enlarged cerebral ventricles due to hydrocephalus are also common in Aicardi syndrome.

Amniotic band syndrome is often difficult to detect before birth as the individual strands are small and hard to see on ultrasound. Often the bands are detected indirectly because of the constrictions and swelling upon limbs, digits, etc. Misdiagnosis is also common, so if there are any signs of amniotic bands, further detailed ultrasound tests should be done to assess the severity. 3D ultrasound and MRI can be used for more detailed and accurate diagnosis of bands and the resulting damage/danger to the fetus.

Therapy can help developmental delays, as well as physiotherapy for the low muscle tone. Exercise and healthy eating can reduce weight gain. Treatments are available for seizures, eczema, asthma, infections, and certain bodily ailments.

Prognosis varies widely depending on severity of symptoms, degree of intellectual impairment, and associated complications. Because the syndrome is rare and so newly identified, there are no long term studies.

Treatment is symptomatic, and may include anti-seizure medication and special or supplemental education consisting of physical, occupational, and speech therapies.

Pathologically, PMG is defined as “an abnormally thick cortex formed by the piling upon each other of many small gyri with a fused surface.” To view these microscopic characteristics, magnetic resonance imaging (MRI) is used. First physicians must distinguish between polymicrogyria and pachygyria. Pachygria leads to the development of broad and flat regions in the cortical area, whereas the effect of PMG is the formation of multiple small gyri. Underneath a computerized tomography (CT scan) scan, these both appear similar in that the cerebral cortex appears thickened. However, MRI with a T1 weighted inversion recovery will illustrate the gray-white junction that is characterized by patients with PMG. An MRI is also usually preferred over the CT scan because it has sub-millimeter resolution. The resolution displays the multiple folds within the cortical area, which is continuous with the neuropathology of an infected patient.

Laboratory: normal metabolic and infective screening. An increase in the number of white cells (particularly lymphocytes) in the CSF, and high levels of interferon-alpha activity and neopterin in the CSF are important clues - however, these features are not always present. More recently, a persistent elevation of mRNA levels of interferon-stimulated gene transcripts have been recorded in the peripheral blood of almost all cases of AGS with mutations in "TREX1", "RNASEH2A", "RNASEH2C", "SAMHD1", "ADAR1" and "IFIH1", and in 75% of patients with mutations in "RNASEH2B". These results are irrespective of age. Thus, this interferon signature appears to be a very good marker of disease.

Genetics: pathogenic mutations in any of the seven genes known to be involved in AGS.

Diagnosis of megalencephaly has changed over the years, however, with the development of more advanced equipment, physicians have been able to confirm the disorder with better accuracy. Usually, a physical exam is first performed when characteristics of megalencephaly have appeared. This typically occurs at birth or during early child development. A physician will then take head measurements in order to determine the circumference. This is known as the head circumference. Then a family background will be recorded in order to determine if there has been a history of megalencephaly in the family.

A neurological exam will then be performed using the technology of an MRI machine in order to confirm the diagnosis of megalencephaly. These imaging tests give detailed information regarding brain size, volume asymmetry and other irregular developments linked with MCAP, MPPH and hemimegalencephaly.

There is also a strong correlation of epilepsy and megalencephaly and this can aid doctors in their diagnosis.

If a diagnosis of megalencephaly is confirmed, the child is referred to a specialist who focuses on managing the symptoms and improving lifestyle. Since megalencephaly is usually presented with autism, the goal of treatment is to improve deficiencies associated with autistic causes. Additionally, since each patient has unique symptoms, there is no one specific treatment method and therefore is heavily reliant on symptoms associated with an individual.

Prenatal Diagnosis:

- Aymé, "et al." (1989) reported prenatal diagnosis of Fryns syndrome by sonography between 24 and 27 weeks.

- Manouvrier-Hanu et al. (1996) described the prenatal diagnosis of Fryns syndrome by ultrasonographic detection of diaphragmatic hernia and cystic hygroma. The diagnosis was confirmed after termination of the pregnancy. The fetus also had 2 erupted incisors; natal teeth had not been mentioned in other cases of Fryns syndrome.

Differential Diagnosis:

- McPherson et al. (1993) noted the phenotypic overlap between Fryns syndrome and the Pallister–Killian syndrome (601803), which is a dysmorphic syndrome with tissue-specific mosaicism of tetrasomy 12p.

- Veldman et al. (2002) discussed the differentiation between Fryns syndrome and Pallister–Killian syndrome, noting that differentiation is important to genetic counseling because Fryns syndrome is an autosomal recessive disorder and Pallister–Killian syndrome is usually a sporadic chromosomal aberration. However, discrimination may be difficult due to the phenotypic similarity. In fact, in some infants with 'coarse face,' acral hypoplasia, and internal anomalies, the initial diagnosis of Fryns syndrome had to be changed because mosaicism of isochromosome 12p was detected in fibroblast cultures or kidney tissue. Although congenital diaphragmatic hernia is a common finding in both syndromes, bilateral congenital diaphragmatic hernia had been reported only in patients with Fryns syndrome until the report of the patient with Pallister–Killian syndrome by Veldman et al. (2002).

- Slavotinek (2004) reviewed the phenotypes of 52 reported cases of Fryns syndrome and reevaluated the diagnostic guidelines. She concluded that congenital diaphragmatic hernia and distal limb hypoplasia are strongly suggestive of Fryns syndrome, with other diagnostically relevant findings including pulmonary hypoplasia, craniofacial dysmorphism, polyhydramnios, and orofacial clefting. Slavotinek (2004) stated that other distinctive anomalies not mentioned in previous guidelines include ventricular dilatation or hydrocephalus, agenesis of the corpus callosum, abnormalities of the aorta, dilatation of the ureters, proximal thumbs, and broad clavicles.

The diagnosis of lissencephaly is usually made at birth or soon after by ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI). However, these results should be interpreted cautiously since even experienced radiologists can misdiagnose polymicrogyria, a different developmental malformation of the brain, as lissencephaly.

Before birth, complex ultrasounds performed routinely during pregnancy may indicate the presence of cerebral abnormality, but this method of diagnosis should be complemented by other methods, such as genetic studies and NMR, and the examination is not recommended as part of routine ultrasound examinations, unless family medical history or other reasons for suspecting brain malformation are present. The earliest point during gestation when it is possible to observe abnormal development of the brain surface is approximately in week 20, although ultrasound examinations in week 25–30 are more common. Up to this time, the fetal brain normally has a smooth appearance. If lissencephaly is suspected, chorionic villus sampling can test for some lissencephaly variants, but only those with a known genetic mutation.

Gross examination exposes a pattern of many small gyri clumped together, which causes an irregularity in the brain surface. The cerebral cortex, which in normal patients is six cell layers thick, is also thinned. As mentioned prior, the MRI of an infected patient shows what appears to be a thickening of the cerebral cortex because of the tiny folds that aggregate causing a more dense appearance. However gross analysis shows an infected patient can have as few as one to all six of these layers missing.

At the moment there are no therapies specifically targeting the underlying cause of AGS. Current treatments address the symptoms, which can be varied both in scope and severity. Many patients benefit from tube-feeding. Drugs can be administered to help with seizures / epilepsy. The treatment of chilblains remains problematic, but particularly involves keeping the feet / hands warm. Physical therapy, including the use of splints can help to prevent contractures and surgery is sometimes required. Botox (botulinium toxin) has sometimes caused severe immune reactions in some AGS patients, and the high risk of possible further brain damage must be considered before giving Botox. Occupational therapy can help with development, and the use of technology (e.g. Assistive Communication Devices) can facilitate communication. Patients should be regularly screened for treatable conditions, most particularly glaucoma and endocrine problems (especially hypothyroidism). The risk versus benefit of giving immunizations also must be considered, as some AGS patients have high immune responses or flares that cause further brain damage from immunizations but other patients have no problems with immunizations; on the other hand, AGS patients have died from illnesses that can be immunized against, so the family must consider the risk vs. benefit of each immunization vs. risk of the actual virus if they choose not to immunize. As of 2017, there are current drug trials being conducted that may lead to drug treatments for AGS.

Surgical correction is recommended when a constriction ring results in a limb contour deformity, with or without lymphedema.

When seizures are present in any forms of cortical dysplasia, they are resistant to medication. Frontal lobe resection provides significant relief from seizures to a minority of patients with periventricular lesions.

Treatment is symptomatic, often addressing indicators associated with peripheral pulmonary artery stenosis. Laryngotracheal calcification resulting in dyspnea and forceful breathing can be treated with bronchodilators including the short and long-acting β2-agonists, and various anticholinergics. Prognosis is good, yet life expectancy depends on the severity and extent of diffuse pulmonary and arterial calcification.

Detection of heterotopia generally occurs when a patient receives brain imaging—usually an MRI or CT scan—to diagnose seizures that are resistant to medication. Correct diagnosis requires a high degree of radiological skill, due to the heterotopia's resemblance to other masses in the brain.