Diagnosis
N. fowleri can be grown in several kinds of liquid axenic media or on non-nutrient agar plates coated with bacteria. Escherichia coli can be used to overlay the non-nutrient agar plate and a drop of cerebrospinal fluid sediment is added to it. Plates are then incubated at 37 °C and checked daily for clearing of the agar in thin tracks, which indicate the trophozoites have fed on the bacteria.Detection in water is performed by centrifuging a water sample with E. coli added, then applying the pellet to a non-nutrient agar plate. After several days, the plate is microscopically inspected and Naegleria cysts are identified by their morphology. Final confirmation of the species identity can be performed by various molecular or biochemical methods.Confirmation of Naegleria presence can be done by a so-called flagellation test, where the organism is exposed to a hypotonic environment (distilled water). Naegleria, in contrast to other amoebae, differentiates within two hours into the flagellate state. Pathogenicity can be further confirmed by exposure to high temperature (42 °C): Naegleria fowleri is able to grow at this temperature, but the nonpathogenic Naegleria gruberi is not.
This indicates that the defective gene responsible for a disorder is located on an autosome (chromosomes 12 and 17 are autosomes), and only one copy of the defective gene is sufficient to cause the disorder, when inherited from a parent who has the disorder. Diagnosis
Differential diagnosis
It is often mistaken for leukoplakia.The differential diagnosis also includes hyperplastic candidiasis and frictional keratosis

Classification
The ICD-10 lists WSN under "other congenital malformations of mouth". It could be classified as a skin condition, or more precisely as a genodermatosis (a genetically determined skin disorder). Treatment
There is no treatment, but because this is a benign condition with no serious clinical complications, prognosis is excellent. See also
Oral melanosis
List of cutaneous conditions caused by mutations in keratins
Hereditary benign intraepithelial dyskeratosis

References
External links
White sponge nevus of cannon; Leukokeratosis, hereditary mucosal at NIHs Office of Rare Diseases