WHAT IS KABUKI SYNDROME?

Overview

Kabuki Syndrome (KS) is a rare genetic disorder first identified and described in 1981 by two Japanese groups, led by scientists Norio Niikawa and Yoshikazu Kuroki. It is named Kabuki Syndrome because of the facial resemblance of affected individuals to stage makeup used in kabuki, a form of traditional Japanese theater.  Given the relative recency of identification, there is still much to learn about the syndrome. 

 

Scientists do know that KS is considered to be a Mendelian Disorder of the Epigenetic Machinery. In layman's terms, this refers to the biological mechanisms that are responsible for how genes are expressed or turned "on" or "off" (i.e. our genes are responsible for determining the specific structure and function of individual cells in our body, or what "job" they are supposed to do).  When there is a disruption in how certain genes are expressed, it can have widespread epigenetic consequences, meaning, that there may be abnormal cell development leading to adverse health effects or physical characteristics.

 

To date, two genes have been identified where mutations can occur that cause Kabuki Syndrome.  The KMT2D (formerly MLL2) gene mutation is thought to be responsible for approximately 75% of cases while mutations of the KDM6A gene have been discovered in 9% of individuals who tested negative for KMT2D gene mutation.  In most cases, there is not a history of the syndrome in a family.  Targeted genetic testing is available for both known genes.  It is expected that there are other gene mutations that may cause Kabuki Syndrome that have yet to be identified.  

 

There is currently no cure for Kabuki syndrome, so medical management of the syndrome has thus far focused on treating symptoms and phenotypic manifestations.

Who is affected?

Kabuki Syndrome affects males and females in equal numbers. Although the disorder was first reported in Japan, Kabuki Syndrome has since been reported in a wide variety of different ethnic groups. The incidence of Kabuki Syndrome is unknown, but has been estimated to be at least one in 32,000 births in the general population. Kabuki Syndrome has historically been difficult to diagnose, especially with little awareness among medical professionals. With increased availability of genetic testing it is expected that many more cases will be identified and properly diagnosed (some estimate it may be closer to one in 10,000 births).

Characteristics of Kabuki Syndrome

There are many signs and symptoms which can occur in individuals with Kabuki Syndrome, though not all are seen in every person:

  • Intellectual disability

  • Seizures

  • Cardiac abnormalities

  • Urogenital and kidney problems

  • Immune deficiencies

  • Anxiety

  • Skeletal abnormalities, growth deficiency and joint hyper-mobility

  • Diminished muscle tone

  • Feeding difficulties & gastrointestinal abnormalities

  • Dental abnormalities

  • Cleft lip and palate

  • Speech delays

  • Ear infections and hearing loss

  • Dysmorphic facial features (e.g., arched, interrupted eyebrows, misaligned eyes, long opening between eyelids, broad nose with depressed nasal tip)

  • Large and low-set ears

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