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.

The diagnosis is usually based on clinical features present at birth.

Ultrasound in the second trimester may show abnormalities associates with NLS, including polyhydramnios, intrauterine growth restriction, microcephaly, proptosis and decreased fetal motility.

There is no known cure for microcephaly. Treatment is symptomatic and supportive.

The prognosis is poor; affected individuals are either stillborn or die shortly after birth. The longest survival reported in literature is of 134 days.

This syndrome is transmitted as an autosomal recessive disorder and there is a risk for recurrence of 25% in future pregnancies.

Suspicion of a chromosome abnormality is typically raised due to the presence of developmental delays or congenital malformations. Diagnosis of tetrasomy 18p is typically made via a routine chromosome analysis from a blood sample. The diagnosis can also be made prenatally by chorionic villus sampling or amniocentesis.

Severity of tetrasomy 18p is variable. Individuals with mosaicism are typically less severely affected than non-mosaic individuals.

Diagnosing colpocephaly prenatally is difficult because in many cases signs start to appear after birth. Prenatal diagnosis is made by detecting enlargement of either or both occipital horns of the lateral ventricles. Usually prenatal ultrasounds don't show cephalic abnormalities and in cases that they do show abnormality is of low accuracy, making it difficult to diagnose colpocephaly. Often, abnormalities in prenatal ultrasounds can be misdiagnosed as hydrocephalus.

At present, treatment for tetrasomy 18p is symptomatic, meaning that the focus is on treating the signs and symptoms of the conditions as they arise. The Chromosome 18 Clinical Research Center has published a list of recommended screening and evaluations:

After birth, MR imaging can be done to look for cephalic abnormalities. This is the most commonly used method for diagnosing colpocephaly. Physicians look for abnormally large occipital horns of the lateral ventricles and diminished thickness of white matter. Spinal tapping is not a preferred method for diagnosis because newborn babies with colpocephaly or hydrocephaly have open fontanelles which makes it difficult to collect CSF. Also, colpocephaly is not associated with increased pressure.

Diagnosis is achieved by examining the structure of the chromosomes through karyotyping; while once born, one can do the following to ascertain a diagnosis of the condition:

- MRI

- EEG

Kaufman oculocerebrofacial syndrome differential diagnosis consists of:

Diagnosis is based on the distinctive cry and accompanying physical problems. These common symptoms are quite easily observed in infants. Affected children are typically diagnosed by a doctor or nurse at birth. Genetic counseling and genetic testing may be offered to families with individuals who have cri du chat syndrome. Prenatally the deletion of the cri du chat related region in the p arm of chromosome 5 can be detected from amniotic fluid or chorionic villi samples with BACs-on-Beads technology. G-banded karyotype of a carrier is also useful. Children may be treated by speech, physical and occupational therapists. Heart abnormalities often require surgical correction.

The diagnosis of Kaufman oculocerebrofacial syndrome can be achieved via molecular testing approaches. Additionally to ascertain if the individual has the condition:

- Growth assessment

- Thyroid function evaluation

- Kidney ultrasound

- Echocardiogram

FHS shares some common features with Rubinstein–Taybi (due to overlapping effects of mutations on SRCAP), however cranial and hand anomalies are distinctive: broad thumbs, narrow palate, and microcephaly are absent in Floating-Harbor Syndrome. One child in the UK has a diagnosis of microcephaly alongside Floating–Harbor syndrome.

Assisted reproductive technology (ART) is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. According to the CDC, in general, ART procedures involve surgically removing eggs from a woman's ovaries, combining them with sperm in the laboratory, and returning them to the woman's body or donating them to another woman. ART has been associated with epigenetic syndromes, specifically BWS and Angelman syndrome. Three groups have shown an increased rate of ART conception in children with BWS. A retrospective case control study from Australia found a 1 in 4000 risk of BWS in their in-vitro population, several times higher than the general population. Another study found that children conceived by in vitro fertilisation (IVF) are three to four times more likely to develop the condition. No specific type of ART has been more closely associated with BWS. The mechanism by which ART produces this effect is still under investigation.

Until recently, doctors have diagnosed patients with FHS based on clinical observations and how well they fit the disease description, usually occurring in early childhood. Molecular genetic testing is also used now to test for genetic mutations. By performing a sequence analysis test of select exons, mutations can be detected in exon 34 of the SRCAP gene. This mutation has been observed in 19 patients to date.

In most cases, if the patient shows classic facial features of FHS, the molecular testing will show a mutation on the SRCAP gene.

After the dropping of atomic bombs "Little Boy" on Hiroshima and "Fat Man" on Nagasaki, several women close to ground zero who had been pregnant at the time gave birth to children with microcephaly. Microcephaly prevalence was seven of a group of 11 pregnant women at 11–17 weeks of gestation who survived the blast at less than from ground zero. Due to their proximity to the bomb, the pregnant women's "in utero" children received a biologically significant radiation dose that was relatively high due to the massive neutron output of the lower explosive-yielding Little Boy. Microcephaly is the only proven malformation, or congenital abnormality, found in the children of Hiroshima and Nagasaki.

Most children (>80%) with BWS do not develop cancer; however, children with BWS are much more likely (~600 times more) than other children to develop certain childhood cancers, particularly Wilms' tumor (nephroblastoma), pancreatoblastoma and hepatoblastoma. Individuals with BWS appear to only be at increased risk for cancer during childhood (especially before age four) and do not have an increased risk of developing cancer in adulthood. If 100 children with BWS were followed from birth until age ten, about 10 cases of cancer would be expected in the group before age four, and about 1 case of cancer in the group would be expected between age four and ten.

In addition to Wilms tumor and hepatoblastoma, children with BWS have been shown in individual case reports to develop ganglioneuroma, adrenocortical carcinoma, acute lymphoid leukemia, liver sarcoma, thyroid carcinoma, melanoma, rhabdomyosarcoma, and mesoblastic nephroma.

Wilms tumor, hepatoblastoma, and mesoblastic nephroma can usually be cured if diagnosed early. Early diagnosis allows physicians to treat the cancer when it is at an early stage. In addition, there is less toxic treatment. Given the importance of early diagnosis, all children with BWS should receive cancer screening.

An abdominal ultrasound every 3 months until at least eight years of age is recommended and a blood test to measure alpha-fetoprotein (AFP) every 6 weeks until at least four years of age. Families and physicians should determine screening schedules for specific patients, especially the age at which to discontinue screening, based upon their own evaluation of the risk-benefit ratio.

Macrocephaly is customarily diagnosed if head circumference is greater than two standard deviations (SDs) above the mean. Relative macrocephaly occurs if the measure is less than two SDs above the mean, but is disproportionately above that when ethnicity and stature are considered. In research, cranial height or brain imaging is also used to determine intracranial volume more accurately.

Ring chromosome 14 syndrome is extremely rare, the true rate of occurrence is unknown (as it is "less than" 1 per 1,000,000), but there are at least 50 documented cases in the literature.

There is no specific treatment for micro syndrome, but there are ways to help the disorders, and illnesses that come with it. Many individuals with Micro Syndrome need permanent assistance from their disorders and inabilities to move and support themselves. Seizures are not uncommon and patients should get therapy to help control them, and many patients also require wheelchairs to move, so an assistant would be needed at all times.

Those with micro syndrome are born appearing normal. At the age of one, mental and physical delays become apparent, along with some limb spasms. By the age of eight micro syndrome has already set in, and the patient will have joint contractures, Ocular Atrophy will become noticeable, the patient will most likely lose ability to walk, speak, and sometimes move at all.

Even though clinical diagnostic criteria have not been 100 percent defined for genitopatellar syndrome, the researchers stated that the certain physical features could relate to KAT6B mutation and result in the molecular genetic testing. The researchers stated that the Individuals with two major features or one major feature and two minor features are likely to have a KAT6B mutation.

To diagnose the Genitopatellar Syndrome, there are multiple ways to evaluate.

Medical genetics consultation

- Evaluation by developmental specialist

- Feeding evaluation

- Baseline hearing evaluation

- Thyroid function tests

- Evaluation of males for cryptorchidism

- Orthopedic evaluation if contractures are present or feet/ankles are malpositioned

- Hip radiographs to evaluate for femoral head dislocation

- Renal ultrasound examination for hydronephrosis and cysts

- Echocardiogram for congenital heart defects

- Evaluation for laryngomalacia if respiratory issues are present

- Evaluation by gastroenterologist as needed, particularly if bowel malrotation is suspected

Though only definitively diagnosable by genetic sequence testing, including a G band analysis, ATR-16 syndrome may be diagnosed from its constellation of symptoms. It must be distinguished from ATR-X syndrome, a very similar disease caused by a mutation on the X chromosome, and cases of alpha-thalassemia that co-occur with intellectual disabilities with no underlying genetic relationship.

Edwards syndrome occurs in about one in 5,000 live births, but more conceptions are affected by the syndrome because the majority of those diagnosed with the condition prenatally will not survive to birth. Although women in their 20s and early 30s may conceive babies with Edwards syndrome, the risk of conceiving a child with it increases with a woman's age. The average maternal age for conceiving a child with this disorder is 32½.

Treatments for ATR-16 syndrome depend on the symptoms experienced by any individual. Alpha thalassemia is usually self-limiting, but in some cases may require a blood transfusion or chelating treatment.