[1][2] It affects multiple parts of the body, with varying symptoms and severity, although the most common is the characteristic facial appearance.

[3] Most people with Kabuki syndrome have distinctive facial features that include arched eyebrows, long eyelashes, elongated eyelids with lower lids that turn out, prominent ears, a flat tip of the nose and a downward slant to the mouth.

[3][4][6] Infants and young children often experience difficulties relating to hypotonia, feeding issues/failure to thrive, infections, surgical repair of heart and palate defects and developmental delays.

In addition, intellectual impairment, difficulty with visuospatial tasks and maintaining attention usually require an individualized education plan (IEP) if the child attends public school.

[7] Type 1 Kabuki syndrome is caused by germline heterozygous loss of function variants in KMT2D (formerly known as the MLL2), located on human chromosome 12.

[14] Most cases of Kabuki syndrome occur de novo, that is, the parents are unaffected and the gene was mutated early in embryological development.

[4] These may represent individuals with types of mutations that are challenging to detect via current routine investigations or patients who have disorders that share some features with Kabuki syndrome.

Most of these mutations are in the KMT2D gene and involve a change in amino acid sequence that creates a shortened and nonfunctional chromatin-modifying enzyme.

[3] When genetic testing is not available, Kabuki syndrome is diagnosed clinically (through identifying symptoms, physical exams, and lab results), most commonly by a geneticist.

[10] The authors propose that a definitive diagnosis can be made in an individual of any age with a history of infantile hypotonia, developmental delay and/or intellectual disability, and one or both of the following major criteria: Further criteria for a probable and possible diagnosis, including a table of suggestive clinical features, were included in the publication.

[15] If congenital heart disease is present, prophylactic antibiotics may be recommended before any procedures such as dental work that might cause infection.

Some patients have coexisting conditions which may shorten life expectancy, such as hypoplastic left heart syndrome or kidney dysfunction.

Several European groups based in Italy, France, Germany and the Netherlands are also actively working on improving understanding of the condition and to identifying potential treatments.

In 1969, Norio Niikawa MD, a geneticist in Japan, was treating a child patient presenting with unique facial characteristics and various health problems.

Many of the children presenting with this diagnosis had unusual, elongated lower eyelids, and this feature was reminiscent of the theatrical make-up worn by actors in Kabuki theatre.

[18][29] As reported by Dr. Niikawa "The name, 'Kabuki make-up', of the syndrome was given by myself, because the facial appearance of patients, especially eversion of their lower eyelids, is reminiscent of the makeup of actors in Kabuki, the traditional form of Japanese theater.

Kabuki actors usually apply traditional makeup to strengthen their eyes, especially in a hero play, and they are very proud of their performing art.